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Hire Dr. Paranjayee Mandal

United Kingdom

USD 60 /hr

Materials Engineer. Expertise in PVD coatings, Tribology, Metal forming, Materials characterisation.

Profile Summary

My expertise is in the field of PVD coatings, Tribology in coating and metal forming, microstructural evolution of aerospace alloys, advanced material characterisation etc.

Subject Matter Expertise

• ★ Surface Sciences
• ★ Materials Engineering
• ★ Tribology
• ☆ Mechanical Engineering
• ☆ Powders & Bulk Materials
• ☆ Metals
• ☆ Materials Science

Services

• Scientific consulting
• Product development
• Scientific writing
• Data science & analysis
• Academic research

Scientific consulting Technical consulting, Idea discussion, Data analytics, Survey/study

Product development Material sourcing

Scientific writing White paper, Journal article, Review article, Educational content

Data science & analysis Simple data analysis, Complex data analysis, Statistical analysis

Academic research Qualitative research, Internet research, Systematic reviews and meta-analysis, Review article, Secondary data compilation, Statistical review of research data, Literature search

Work Experience

University of Strathclyde

- Present

Education

PhD (Materials and Engineering Research Institute (MERI))

Sheffield Hallam University

2012 - 2015

M.Tech (Department of Mechanical Engineering)

Indian Institute of Technology Kharagpur

2009 - 2011

B.E (Production Engineering Department)

Jadavpur University

2005 - 2009

Certifications

• Certification details not provided.

Publications

JOURNAL ARTICLE

Cold forming of Al-5251 and Al-6082 tailored welded blanks manufactured by laser and electron beam welding @article{941927c818b54f3d93173ac4594a9bb8, title = "Cold forming of Al-5251 and Al-6082 tailored welded blanks manufactured by laser and electron beam welding", abstract = "This work demonstrates applicability of electron beam welding (EBW) and laser beam welding (LBW) techniques for manufacture of tailored welded blanks (TWBs) from Al-5251 (H22) and Al-6082 (T6) sheets. A combination of dissimilar sheets as well as thicknesses (1.5 mm and 2.5 mm) has been used in addition to a similar combination. An optimal post-weld heat treatment (PWHT) was determined that was effective in relieving stresses and impart adequate ductility in the TWBs allowing cold forming (i.e. stamping), into a cruciform geometry, at ambient temperature. Pull tests revealed marked improvement in elongation for all the welds, including all combinations, after PWHT. Micro-hardness mapping of the weld sections showed transition from a non-uniform to a more uniform distribution via slight increase in hardness of the weld region whilst decrease in the hardness of the parent materials. Non-contact optical measurement using GOM camera showed minimal localised thinning in steep angled areas of the cruciform geometry. The dissimilar LBW TWBs, after PWHT, showed noticeable increase in elongation, homogeneous hardness distribution and slightly refined microstructure in the fusion zone (FZ) compared to their EBW counterparts.", keywords = "Aluminium alloys, Cold forming, Electron beam welding (EBW), Laser beam welding (LBW), Post-weld heat treatment (PWHT), Stamping, Tailor welded blanks (TWBs), Weld microstructure", author = "Himanshu Lalvani and Paranjayee Mandal", year = "2021", month = aug, day = "1", doi = "10.1016/j.jmapro.2021.06.070", language = "English", volume = "68", pages = "1615--1636", journal = "Journal of Manufacturing Processes", issn = "1526-6125", publisher = "Elsevier", number = "Part A", } . Journal of Manufacturing Processes.

Paranjayee Mandal, Himanshu Lalvani(2021). Cold forming of Al-5251 and Al-6082 tailored welded blanks manufactured by laser and electron beam welding . Journal of Manufacturing Processes. 68. p. 1615--1636. Elsevier {BV}

Role of the secondary phase η during high temperature compression of ATI 718PlusR @article{700c1e24ca194a58ad20ddb020b683ec, title = "Role of the secondary phase η during high temperature compression of ATI 718PlusR", abstract = "High-temperature compression tests were performed on a Ni-base superalloy with a multi-phase microstructure. Particular attention was given on the influence of the η phase on recrystallization of ATI 718Plus{\textregistered}. The compression tests were performed at two temperatures over a variety of strains and strain rates. Meta-dynamic recrystallization was studied by exposing the samples to a set dwell time at the test temperature after deformation. Electron backscatter diffraction (EBSD) was used to investigate the microstructures after the tests. Secondary electron imaging (SEI) and scanning transmission electron microscopy (STEM) were utilized in order to investigate the deformation behavior of η and obtaining a detailed understanding of the recrystallization mechanism. The secondary η phase was found to increase the recrystallized fraction compared to η free tests. However, clusters of thin lamellar η inhibited recrystallization. The flow curve softening was distinctly stronger in the microstructure containing precipitates. It could be shown by SE images that this was due to the breakage and realignment of η. In addition, η was also found to accommodate the stresses by a remarkable deformation without breaking up. This was considered to be due to the composite nature of the precipitate as well as the ongoing recrystallization in the surrounding matrix.", keywords = "two phase microstructure, superalloy, high temperature compression, deformation twinning", author = "Christiane Kienl and Paranjayee Mandal and Himanshu Lalvani and Rae, {Catherine M. F.}", year = "2020", month = aug, day = "1", doi = "10.1007/s11661-020-05837-7", language = "English", volume = "51", pages = "4008--4021", journal = "Metallurgical and Materials Transactions A", issn = "1073-5623", publisher = "ASM International", number = "8", } . Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science.

Impact of a multi-step heat treatment on different manufacturing routes of 18CrNiMo7-6 steel @article{24a3c4de04c9487f8187a5001b29282b, title = "Impact of a multi-step heat treatment on different manufacturing routes of 18CrNiMo7-6 steel", abstract = "Effect of an optimized multi-step heat treatment routine on conventional (machining from wrought bar stock) and alternate manufacturing routes (hot forging and cold rotary forging) for producing flat cylindrical-shaped machine drive components from 18CrNiMo7-6 steel was investigated. The microstructure and mechanical properties of the final component manufactured using these three different routes were analyzed using optical microscopy, electron backscatter diffraction (EBSD), hardness testing, electro-thermal mechanical testing (ETMT), and rotary bending fatigue testing (RBFT) before and after implementing the multi-step heat treatment. It was found that the multi-step heat treatment transformed the as-received microstructure into the tempered martensitic microstructure, improving hardness, tensile, and fatigue properties. The heat treatment produced desired properties for the components manufactured by all three different routes. However the cold rotary forging, which is the most material utilizing route over the others, benefited the most from the optimized heat treatment.", keywords = "hot forging, cold rotary forging, heat treatment, microstructure, tensile properties, fatigue properties", author = "Paranjayee Mandal and Maider Olasolo and {Da Silva}, Laurie and Himanshu Lalvani", year = "2020", month = jun, day = "30", doi = "10.1007/s11661-020-05728-x", language = "English", volume = "51", pages = "3009–3029", journal = "Metallurgical and Materials Transactions A", issn = "1073-5623", publisher = "ASM International", number = "6", } . Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science.

Paranjayee Mandal, Maider Olasolo, Laurie Da Silva, Himanshu Lalvani(2020). Impact of a Multi-step Heat Treatment on Different Manufacturing Routes of 18CrNiMo7-6 Steel . Metallurgical and Materials Transactions A. 51. (6). p. 3009--3029. Springer Science and Business Media {LLC}

A study on microstructural evolution in cold rotary forged nickel-superalloys @article{6db0def1649449d2bb0b2325a1f88af7, title = "A study on microstructural evolution in cold rotary forged nickel-superalloys: C263 and Inconel 718", abstract = "C263 and Inconel 718 are precipitation hardenable nickel-superalloys widely used in different sections of a gas turbine engine dependent on their strength and temperature capability. Cold rotary forging is an effective route for manufacturing axisymmetric components with significantly higher material utilisation as compared to machining from conventional hot forgings. This paper presents a study on how C263, an alloy system strengthened by γ', and Inconel 718, an alloy system strengthened by γ'' and δ, deform during the cold rotary forging process and how their microstructures evolve. The two alloys exhibit maximum formability in solution-annealed condition. In this study, both C263 and Inconel 718 were annealed before the cold rotary forging operation. Parts with a 90° bend flange were successfully cold rotary forged from tubular preforms with a wall thickness of 6 mm. For both the alloys, the cold rotary forged parts exhibit significant differences in material properties from the undeformed sections to the most deformed section (i.e. the flanges). Post-forging heat-treatments are required to impart the desired material properties throughout the part. Therefore, appropriate annealing and aging treatments were identified for each of the two alloys. These heat-treatments led to uniform material properties for both deformed and undeformed sections of the cold rotary forged flanges in case of both the alloys. ", keywords = "cold rotary forging, C263, inconel 718, microstructure", author = "Paranjayee Mandal and Himanshu Lalvani and Kyle Watt and Alastair Conway and Martin Tuffs", year = "2020", month = apr, day = "26", doi = "10.1016/j.promfg.2020.04.296", language = "English", volume = "47", pages = "1403--1409", journal = "Procedia Manufacturing", issn = "2351-9789", publisher = "Elsevier", number = "C", note = "23rd International Conference on Material Forming - 1st virtual ESAFORM conference, ESAFORM 2020 ; Conference date: 04-05-2020 Through 06-05-2020", url = "https://esaform2020.org/", } . Procedia Manufacturing.

Microstructural evolution of SA508 grade 3 steel during hot deformation @article{939cdb0923624ceda25b182817394c12, title = "Microstructural evolution of SA508 grade 3 steel during hot deformation", abstract = "SA508 grade 3 steel is widely used in the manufacture of large-scale forged components for nuclear reactor applications. Numerical models have already been established to simulate industrial forging process of grade 3 steel; however, limited information is available on the microstructural evolution of this steel during hot forging operation. This work focuses on the flow behavior and related microstructural evolution in grade 3 steel with detailed analysis on the interfacial friction, texture and hardness evolution. Uniaxial hot compression tests were conducted over a range of test temperatures (880-1130 °C) and true strain rates (0.001-1/s), representative of the industrial hot forging conditions. Two different deformation mechanisms, MDRX at the lowest forging temperature and DRV along with DRX at the highest forging temperature, were observed showing marked impact on the final microstructure and hardness. A random fiber-type weak deformation texture was observed irrespective of the test temperatures and strain rates used. The microstructural changes from the as-received to the various deformed conditions were quantified. The quantitative data are the key to obtain accurate parameters for DRV and DRX processes that affect the accuracy of the mathematical models.", keywords = "SA508 grade 3 steel, hot deformation, mechanical properties, microstructural evolution, crystallographic texture, hardness", author = "Paranjayee Mandal and Himanshu Lalvani and Andrew Barrow and Jack Adams", year = "2020", month = feb, day = "29", doi = "10.1007/s11665-020-04611-5", language = "English", volume = "29", pages = "1015--1033", journal = "Journal of Materials Engineering and Performance", issn = "1059-9495", publisher = "ASM International", number = "2", } . Journal of Materials Engineering and Performance.

Paranjayee Mandal, Himanshu Lalvani, Andrew Barrow, Jack Adams(2020). Microstructural Evolution of SA508 Grade 3 Steel during Hot Deformation . Journal of Materials Engineering and Performance. 29. (2). p. 1015--1033. Springer Science and Business Media {LLC}

Mandal, P., Lalvani, H., Barrow, A., Adams, J.(2020). Microstructural Evolution of SA508 Grade 3 Steel during Hot Deformation . Journal of Materials Engineering and Performance. 29. (2). p. 1015-1033.

Characterisation of a high-power impulse magnetron sputtered C/Mo/W wear resistant coating by transmission electron microscopy @article{bd306fc5b0a94c95b1d6e62bd4af1de8, title = "Characterisation of a high-power impulse magnetron sputtered C/Mo/W wear resistant coating by transmission electron microscopy", abstract = "Thin films of C/Mo/W deposited using combined UBM/HIPIMS sputtering show 2–8 nm clusters of material richer in Mo and W than the matrix (found by EDS microanalysis), with structures that resemble graphitic onions with the metal atoms arranged regularly within them. EELS microanalysis showed the clusters to be rich in W and Mo.As the time averaged power used in the pulsed HIPIMS magnetron was increased, the clusters became more defined, larger, and arranged into layers with amorphous matrix between them. Films deposited with average HIPIMS powers of 4 kW and 6 kW also showed a periodic modulation of the cluster density within the finer layers giving secondary, wider stripes in TEM. By analysing the ratio between the finer and coarser layers, it was found that this meta-layering is related to the substrate rotation in the deposition chamber but in a non-straightforward way. Reasons for this are proposed. The detailed structure of the clusters remains unknown and is the subject of further work.Fluctuation electron microscopy results indicated the presence of crystal planes with the graphite interlayer spacing, crystal planes in hexagonal WC perpendicular to the basal plane, and some plane spacings found in Mo2C. Other peaks in the FEM results suggested symmetry-related starting points for future determination of the structure of the clusters.", keywords = "fluctuation electron microscopy, FEM, wear, coatings", author = "Jo Sharp and Muller, {Itzel Castillo} and Paranjayee Mandal and Ali Abbas and Magnus Nord and Alastair Doye and Arutiun Ehiasarian and Papken Hovsepian and Ian Maclaren and Rainforth, {W. Mark}", year = "2019", month = nov, day = "15", doi = "10.1016/j.surfcoat.2019.08.007", language = "English", volume = "377", journal = "Surface and Coatings Technology", issn = "0257-8972", publisher = "Elsevier", } . Surface and Coatings Technology.

(2019). Characterisation of a High-Power Impulse Magnetron Sputtered C/Mo/W wear resistant coating by transmission electron microscopy . Surface and Coatings Technology.

Cold rotary forging of Inconel 718 @article{a70910b936ec4e3ebaf39e84bfc0fd6c, title = "Cold rotary forging of Inconel 718", abstract = "The present work includes an in-depth study of microstructure and mechanical property development in a cold rotary forged component manufactured from Inconel 718 alloy. This work is pioneering in that there is no detailed study available in the literature focussing on cold rotary forging of Inconel 718. A tubular preform of 6 mm wall thickness was cold rotary forged into a 90 degree flange part followed by annealing with double aging. The present study provides a thorough analysis of microstructure, hardness and surface roughness evolution from as-received to final cold rotary forged and heat-treated condition including crystallographic texture changes occurring at different stages. The solution-annealed condition of the preform was found to be most suitable for cold rotary forging of Inconel 718. An annealing treatment followed by double-aging imparted desired properties such as homogeneous microstructure, uniform hardness distribution and improved surface roughness into the cold rotary forged Inconel 718 flange. The cold rotary forging can be a cost-effective route for manufacture of axisymmetric components with high material yield and low buy-to-fly ratio for expensive materials such as Inconel 718.", keywords = "cold rotary forging, Inconel 718, microstructure, texture evolution, surface roughness", author = "Paranjayee Mandal and Himanshu Lalvani and Martin Tuffs", year = "2019", month = oct, day = "1", doi = "10.1016/j.jmapro.2019.08.015", language = "English", volume = "46", pages = "77--99", journal = "Journal of Manufacturing Processes", issn = "1526-6125", publisher = "Elsevier", } . Journal of Manufacturing Processes.

Paranjayee Mandal, Himanshu Lalvani, Martin Tuffs(2019). Cold Rotary Forging of Inconel 718 . Journal of Manufacturing Processes. 46. p. 77--99. Elsevier {BV}

Mandal, P., Lalvani, H., Tuffs, M.(2019). Cold Rotary Forging of Inconel 718 . Journal of Manufacturing Processes. 46. p. 77-99.

Sharp, J., Müller, I.C., Mandal, P., Abbas, A., Nord, M., Doye, A., Ehiasarian, A., Hovsepian, P., MacLaren, I., Rainforth, W.M.(2019). Characterisation of a High-Power Impulse Magnetron Sputtered C/Mo/W wear resistant coating by transmission electron microscopy . Surface and Coatings Technology. 377.

Studies on titanium alloys for aerospace application @article{5fbf4054f93947278539243d3f6df36d, title = "Studies on titanium alloys for aerospace application", abstract = "Since the development of the Ti54M titanium alloy in 2003, its application within the aerospace sector has gradually increased due to the combination of properties such as improved forgeability and machinability, low flow stress at elevated temperatures, and superplastic characteristics. However, for the successful exploitation of Ti54M a comprehensive understanding of its mechanical characteristics, microstructure stability, and superplastic behaviour is required. The superplastic forming of titanium alloys is characterised by high deformation at slow strain rates and high temperatures which influence the material microstructure, and in turn, determine the forming parameters. These mechanisms make the prediction of the material behaviour very challenging, limiting its application within the aerospace industry. Even though Ti54M has been commercially available for over 10 years, further studies of its mechanical and superplastic properties are still required with the aim of assessing its applicability within the aerospace industry as a replacement for other commercial titanium alloys. Therefore, in this work a study of the mechanical and superplastic properties of Ti54M, in comparison with other commercial titanium alloys used in the aerospace industry - i.e. Ti-6AL-4V, and Ti-6-2-4-2 - is presented. The final objective of this study, carried out at the Advanced Forming Research Centre (AFRC, University of Strathclyde, UK), is to obtain material data to calibrate and validate a model capable of estimating the behaviour and grain size evolution of titanium alloys at superplastic conditions.", keywords = "aerospace materials, strain rate sensitivity, superplasticity, titanium alloy", author = "{Gomez Gallegos}, {Ares Argelia} and Paranjayee Mandal and Diego Gonzalez and Nicola Zuelli and Paul Blackwell", year = "2018", month = jul, day = "20", doi = "10.4028/www.scientific.net/DDF.385.419", language = "English", volume = "385", pages = "419--423", journal = "Defect and Diffusion Forum", issn = "1012-0386", publisher = "Trans Tech Publications", } . Defect and Diffusion Forum.

Gomez-Gallegos, A., Mandal, P., Gonzalez, D., Zuelli, N., Blackwell, P.(2018). Studies on titanium alloys for aerospace application . Defect and Diffusion Forum. 385 DDF. p. 419-423.

Friction and wear behaviour of Mo–W doped carbon-based coating during boundary lubricated sliding @article{d764f4e29734419b9985ae2425f44066, title = "Friction and wear behaviour of Mo–W doped carbon-based coating during boundary lubricated sliding", abstract = "A molybdenum and tungsten doped carbon-based coating (Mo–W–C) was developed in order to provide low friction in boundary lubricated sliding condition at ambient and at high temperature. The Mo–W–C coating showed the lowest friction coefficient among a number of commercially available state-of-the-art DLC coatings at ambient temperature. At elevated temperature (200 °C), Mo–W–C coating showed a significant reduction in friction coefficient with sliding distance in contrast to DLC coatings. Raman spectroscopy revealed the importance of combined Mo and W doping for achieving low friction at both ambient and high temperature. The significant decrease in friction and wear rate was attributed to the presence of graphitic carbon debris (from coating) and {\textquoteleft}in-situ{\textquoteright} formed metal sulphides (WS2 and MoS2, where metals were supplied from coating and sulphur from engine oil) in the transfer layer.", keywords = "sliding friction, tribochemical reaction , wear, Raman spectroscopy", author = "Papken Hovsepian and Paranjayee Mandal and Arutiun Ehiasarian and Gy{\"o}rgy S{\'a}fr{\'a}n and Roel Tietema and Dave Doerwald", year = "2016", month = mar, day = "15", doi = "10.1016/j.apsusc.2016.01.007", language = "English", volume = "366", pages = "260--274", journal = "Applied Surface Science", issn = "0169-4332", publisher = "Elsevier", } . Applied Surface Science.

Paranjayee Mandal, Papken Eh. Hovsepian, Arutiun P. Ehiasarian, G. Sáfrán, R. Tietema, D. Doerwald(2016). Friction and wear behaviour of Mo–W doped carbon-based coating during boundary lubricated sliding . Applied Surface Science. 366. p. 260--274. Elsevier {BV}

Hovsepian, P.E., Mandal, P., Ehiasarian, A.P., Sáfrán, G., Tietema, R., Doerwald, D.(2016). Friction and wear behaviour of Mo-W doped carbon-based coating during boundary lubricated sliding . Applied Surface Science. 366. p. 260-274.

Tribological behaviour of Mo − W doped carbon-based coating at ambient condition @article{565415286ab34314807b039fd2b27396, title = "Tribological behaviour of Mo − W doped carbon-based coating at ambient condition", abstract = "Poor adhesion strength and low thermal stability often restrict the tribological applications of the state-of-the-art diamond-like-carbon coatings in automotive industry. A novel carbon-based coating doped with molybdenum and tungsten (Mo−W−C) is deposited using the advantages of HIPIMS to overcome these limitations and to provide enhanced tribological performance. Low friction (µ=0.335 against steel counterpart) and high wear resistance (Kc=3.87×10-16 m3N-1m-1) are observed after 7.5 km sliding distance and the coating remains intact within the wear track after sliding. It is concluded that the tribological performance of Mo−W−C coating at ambient condition excels due to its dense microstructure, interfacial adhesion strength and in-situ formation of solid lubricants such as graphitic carbon particles, MoO3 and Magn{\'e}li phase oxides of molybdenum and tungsten in the transfer layer during sliding.", keywords = "sliding friction, third-body abrasion, wear, Raman spectroscopy", author = "Paranjayee Mandal and Arutiun Ehiasarian and Papken Hovsepian", year = "2015", month = oct, day = "31", doi = "10.1016/j.triboint.2015.04.017", language = "English", volume = "90", pages = "135--147", journal = "Tribology International", issn = "0301-679X", publisher = "Elsevier", } . Tribology International.

Isothermal and dynamic oxidation behaviour of Mo–W doped carbon-based coating @article{891ada2c423c483483aac30d388195d5, title = "Isothermal and dynamic oxidation behaviour of Mo–W doped carbon-based coating", abstract = "The oxidation behaviour of Mo–W doped carbon-based coating (Mo–W–C) is investigated in elevated temperature (400–1000◦C). Strong metallurgical bond between Mo–W–C coating and substrate prevents any sort of delamination during heat-treatment. Isothermal oxidation tests show initial growth of metal oxides at 500◦C, however graphitic nature of the as-deposited coating is preserved. The oxidation progresses with further rise in temperature and the substrate is eventually exposed at 700◦C. The perfor-mance of Mo–W–C coating is compared with a state-of-the-art DLC(Cr/Cr–WC/W:C–H/a:C–H) coating,which shows preliminary oxidation at 400◦C and local delamination of the coating at 500◦C leadingto substrate exposure. The graphitisation starts at 400◦C and the diamond-like structure is completely converted into the graphite-like structure at 500◦C. Dynamic oxidation behaviour of both the coatings is investigated using Thermo-gravimetric analysis carried out with a slow heating rate of 1◦C/min from ambient temperature to 1000◦C. Mo–W–C coating resists oxidation up to ∼800◦C whereas delamination of DLC(Cr/Cr–WC/W:C–H/a:C–H) coating is observed beyond ∼380◦C. In summary, Mo–W–C coating provides improved oxidation resistance at elevated temperature compared to DLC(Cr/Cr–WC/W:C–H/a:C–H)coating.", keywords = "oxidation, thermo-gravimetric analysis, raman spectroscopy", author = "Paranjayee Mandal and Ehiasarian, {Arutiun P.} and Hovsepian, {Papken Eh.}", year = "2015", month = oct, day = "30", doi = "10.1016/j.apsusc.2015.07.057", language = "English", volume = "353", pages = "1291--1309", journal = "Applied Surface Science", issn = "0169-4332", publisher = "Elsevier", } . Applied Surface Science.

Cross sectional TEM analysis of duplex HIPIMS and DC magnetron sputtered Mo and W doped carbon coatings @article{100b0c02f12d456cab4f4b19d2d13a8c, title = "Cross sectional TEM analysis of duplex HIPIMS and DC magnetron sputtered Mo and W doped carbon coatings", abstract = "A FIB lift-out sample was made from a wear-resistant carbon coating deposited by high power impulse magnetron sputtering (HIPIMS) with Mo and W. TEM analysis found columnar grains extending the whole ∼1800 nm thick film. Within the grains, the carbon was found to be organised into clusters showing some onion-like structure, with amorphous material between them; energy dispersive X-ray spectroscopy (EDS) found these clusters to be Mo- and W-rich in a later, thinner sample of the same material. Electron energy-loss spectroscopy (EELS) showed no difference in C-K edge, implying the bonding type to be the same in cluster and matrix. These clusters were arranged into stripes parallel to the film plane, of spacing 7-8 nm; there was a modulation in spacing between clusters within these stripes that produced a second, coarser set of striations of spacing ∼37 nm.", keywords = "carbon coatings, thick film, carbon", author = "J Sharp and {Castillo Muller}, I and P Mandal and A Abbas and G West and Rainforth, {W M} and A Ehiasarian and P Hovsepian", year = "2015", month = "10", day = "12", doi = "10.1088/1742-6596/644/1/012011", language = "English", volume = "644", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing", } . Journal of Physics: Conference Series.

Cross sectional TEM analysis of duplex HIPIMS and DC magnetron sputtered Mo and W doped carbon coatings @article{100b0c02f12d456cab4f4b19d2d13a8c, title = "Cross sectional TEM analysis of duplex HIPIMS and DC magnetron sputtered Mo and W doped carbon coatings", abstract = "A FIB lift-out sample was made from a wear-resistant carbon coating deposited by high power impulse magnetron sputtering (HIPIMS) with Mo and W. TEM analysis found columnar grains extending the whole ∼1800 nm thick film. Within the grains, the carbon was found to be organised into clusters showing some onion-like structure, with amorphous material between them; energy dispersive X-ray spectroscopy (EDS) found these clusters to be Mo- and W-rich in a later, thinner sample of the same material. Electron energy-loss spectroscopy (EELS) showed no difference in C-K edge, implying the bonding type to be the same in cluster and matrix. These clusters were arranged into stripes parallel to the film plane, of spacing 7-8 nm; there was a modulation in spacing between clusters within these stripes that produced a second, coarser set of striations of spacing ∼37 nm.", keywords = "carbon coatings, thick film, carbon", author = "J Sharp and {Castillo Muller}, I and P Mandal and A Abbas and G West and Rainforth, {W M} and A Ehiasarian and P Hovsepian", year = "2015", month = oct, day = "12", doi = "10.1088/1742-6596/644/1/012011", language = "English", volume = "644", journal = "Journal of Physics: Conference Series ", issn = "1742-6588", publisher = "IOP Publishing", } . Journal of Physics: Conference Series.

(2015). Tribological behaviour of Mo–W doped carbon-based coating at ambient condition . Tribology International.

(2015). Isothermal and dynamic oxidation behaviour of Mo–W doped carbon-based coating . APPLIED SURFACE SCIENCE.

Mandal, P., Ehiasarian, A.P., Hovsepian, P.E.(2015). Tribological behaviour of Mo-W doped carbon-based coating at ambient condition . Tribology International. 90. p. 135-147.

Mandal, P., Ehiasarian, A.P., Hovsepian, P.E.(2015). Isothermal and dynamic oxidation behaviour of Mo-W doped carbon-based coating . Applied Surface Science. 353. p. 1291-1309.

Lubricated sliding wear mechanism of chromium-doped graphite-like carbon coating @article{c1794a79b25a44219e9be81e59df41a8, title = "Lubricated sliding wear mechanism of chromium-doped graphite-like carbon coating", abstract = "The current research aims to discuss the tribological behaviour of Chromium-doped graphite-like carbon coatings and suggest a wear mechanism under both dry (in air) and boundary lubricated sliding condition based on phase composition of the wear product generated in wear track during pin-on-disc experiments. As expected, the friction coefficient reduces from 0.22 to 0.12 due to addition of lubricant. Raman analysis indicates that wear mechanism is oxidative in dry sliding condition whereas it is chemically reactive in the presence of lubricant. It is speculated that the key-factor of reduced friction and wear coefficient in lubricated condition is the formation of CrCl3 due to tribochemical reaction between coating and oil. CrCl3 has graphite-like layered structure; therefore it acts like solid lubricant.", keywords = "wear, pin-on-disk, lubrication system", author = "Paranjayee Mandal and Arutiun Ehiasarian and Papken Hovsepian", year = "2014", month = sep, day = "30", doi = "10.1016/j.triboint.2014.04.007", language = "English", volume = "77", pages = "186--195", journal = "Tribology International", issn = "0301-679X", publisher = "Elsevier", } . Tribology International.

Mandal, P., Ehiasarian, A.P., Hovsepian, P.E.(2014). Lubricated sliding wear mechanism of chromium-doped graphite-like carbon coating . Tribology International. 77. p. 186-195.

Effect of deposition parameters on TiAlN coating using pulsed DC CFUBMS @article{2148e5dba5344b878092fd66d1ee423d, title = "Effect of deposition parameters on TiAlN coating using pulsed DC CFUBMS", abstract = "This paper aims to investigate the parametric effect of deposition and target frequency on the mechanical properties and machining performance of the TiAlN coatings deposited in a dual cathode pulsed dc CFUBMS system. Coating composition is not directly dependent on deposition temperature or target frequency individually but increase in both the parameters has led to Al rich coating. The coating thickness is influenced by target frequency only. The fatigue fracture resistance of the TiAlN coating has been evaluated by the nanoimpact test and it has been found to be at least as good as commercial Ti0.5Al0.5N coating deposited on cemented carbide. In dry machining SAE 1037 steel, it has been observed that the resistance to crater wear is influenced by target frequency. Simultaneous increase in the deposition temperature and target frequency has provided improved resistance to crater wear due to their favourable influence on the coating thickness and Al percentage.", keywords = "TiAIN coating, CFUBMS, pulsed DC, machining", author = "P. Mandal and B.D. Beake and S. Paul", year = "2013", month = nov, day = "12", doi = "10.1179/1743294412Y.0000000091", language = "English", volume = "29", pages = "287--295", journal = "Surface Engineering", issn = "0267-0844", publisher = "Maney Publishing", } . Surface Engineering.

Effect of alloyed target vis-à-vis pure target on machining performance of TiAlN coating @article{b3661ba41ede42748a9d4beacf644c40, title = "Effect of alloyed target vis-{\`a}-vis pure target on machining performance of TiAlN coating", abstract = "Typically closed-field unbalanced magnetron sputtering (CFUBMS) and controlled cathodic arc deposition techniques having four or six pure or alloyed targets are employed for commercial titanium aluminium nitride (TiAlN) coating of cutting tools. The role of the use of alloyed target vis-{\`a}-vis pure target on the coating characteristics and the machining performance of TiAlN-coated tools has not been studied in detail. In the present work, TiAlN coating has been deposited on cutting tools using a pulsed DC, dual-cathode CFUBMS system to capture the role of the type of target on machining performance. The deposition rate in the case of the alloyed target has been found to be much higher as compared to the pure target. Such coatings deposited from alloyed targets also provided significantly better machining performance in dry turning of low-carbon and high-carbon steel. Dry turning of SAE 1070 high-carbon steel at 160 m/min did not yield more than 100 μm of average flank wear on the same insert coated using alloyed targets for a machining time of more than 3 min.", keywords = "TiAlN coating, pulsed DC , pure target, alloyed target, machining performance", author = "Paranjayee Mandal and Soumitra Paul", year = "2013", month = may, day = "31", doi = "10.1007/s00170-012-4360-4", language = "English", volume = "66", pages = "721--731", journal = "International Journal of Advanced Manufacturing Technology ", issn = "0268-3768", publisher = "Springer Verlag", number = "5-6", } . International Journal of Advanced Manufacturing Technology.

Mandal, P., Paul, S.(2013). Effect of alloyed target vis-à-vis pure target on machining performance of TiAlN coating . International Journal of Advanced Manufacturing Technology. 66. (5-8). p. 721-731.

Mandal, P., Beake, B.D., Paul, S.(2013). Effect of deposition parameters on TiAlN coating using pulsed DC CFUBMS . Surface Engineering. 29. (4). p. 287-295.

CONFERENCE PAPER

Superplastic behaviour of Ti54M and Ti64 @conference{64db7b4eee96446e91c1b8d2168690bc, title = "Superplastic behaviour of Ti54M and Ti64", abstract = "Even though TIMETAL-54M (Ti-5Al-4V-0.6Mo-0.4Fe or Ti54M) has been commercially available for over 10 years, further study of its superplastic properties is still required in order to assess its applicability within the aerospace industry as a potential replacement for other commercial titanium alloys such as Ti-6Al-4V (Ti64). Ti54M is expected to obtain superplastic characteristics at a lower temperature than Ti64 due to its lower beta-transus temperature. The superplastic forming (SPF) capability of alloys that can be formed at lower temperatures has always attracted the interest of industry as it reduces the grain growth and alpha-case formation, leading to longer life for costly high temperature resistant forming tools.In this work, the SPF characteristics of both Ti54M and Ti64 have been examined by conducting tensile tests according to the ASTM E2448 standard within a range of temperatures and strain values at a fixed strain rate of 1x104/s. A high strain rate sensitivity and uniform deformation at high strains are key indicators in selecting the optimum superplastic temperature. This was observed at 815˚C and 925˚C for Ti54M and Ti64 respectively. The tensile samples were water quenched to freeze their respective microstructure evolution following superplastic deformation and SEM images were captured for grain size and volume fraction of alpha-phase analyses. A slightly higher alpha-grain growth rate was observed during superplastic deformation of Ti64. The initial fine-grain microstructure of Ti54M (~1.6 micron) resulted in a final microstructure with an average grain size of ~3.4 micron and optimum the alpha/beta ratio. Both the fine-grained microstructure and increased amount of beta-volume fraction promotes the superplastic behaviour of Ti54M by grain boundary sliding (GBS). Thus superplastic properties were observed for Ti54M at a lower temperature (~100˚C) than for Ti64.", keywords = "superplastics, Ti54M, superplastic forming, Ti64, superplasticity, materials, aerospace applications", author = "Paranjayee Mandal and Ares Gomez-Gallegos and Diego Gonzalez and Hosam ElRakayby and Paul Blackwell", year = "2019", month = jun, day = "10", language = "English", pages = "1--6", note = "The 14th World Conference on Titanium ; Conference date: 10-06-2019 Through 14-06-2019", } . The 14th World Conference on Titanium, Nantes, France, 10/06/19.

Impact of various heat treatments on the microstructure evolution and mechanical properties of hot forged 18CrNiMo7-6 steel @conference{d11d0e4429cc4e248fac1f5f475b37b7, title = "Impact of various heat treatments on the microstructure evolution and mechanical properties of hot forged 18CrNiMo7-6 steel", abstract = "Carburizing is a method of enhancing the surface properties of components, primarily made from low to medium carbon steels, such as shafts, gears, bearings, etc. Carburized parts are generally quenched and tempered before being put into service; however, after quenching of carburized parts further annealing and hardening treatments can be employed before final tempering. This work analyses the impact of the two aforementioned heat treatment approaches on the development of subsequent microstructures and mechanical properties of hot forged 18CrNiMo7-6 steel. Moreover, this study aims to understand the impact of normalizing treatments prior to the two aforementioned heat treatment routes. Microstructural and mechanical tests were conducted on four as forged flat cylinder components that received a combination of the abovementioned heat treatments. In general, better microstructure refinement, in terms of prior austenite grain size (PAGS), was obtained for carburized parts that received the intermediate annealing and hardening treatments after quenching and prior to the final tempering. Additionally, further refinement of the martensitic pockets/blocks was observed for parts that did not receive a normalising treatment prior to carburisation. The studied heat treatments appear to have a negligible effect on the mechanical properties of the hot forged flat cylinder components. ", keywords = "carburizing, heat treatment, 18CrNiMo7-6 steel", author = "Paranjayee Mandal and {Al Mamun}, Abdullah and Himanshu Lalvani and {Da Silva}, Laurie and Marcos Perez and Lisa Muir", note = "This article is made available as an electronic reprint with the permission of ASM International for the University of Strathclyde Institutional Repository. Reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this article for a fee or for commercial purposes, or modification of the content of this article is prohibited.; Heat Treat 2017 : 29th Heat Treating Society Conference and Exposition ; Conference date: 24-10-2017 Through 26-10-2017", year = "2017", month = oct, day = "24", language = "English", pages = "48--53", url = "http://www.asminternational.org/web/heat-treat-2017", } . Heat Treat 2017, Ohio, United States, 24/10/17.

Mandal, P., Al Mamun, A., Da Silva, L., Lalvani, H., Perez, M., Muir, L.(2017). Impact of various heat treatments on the microstructure evolution and mechanical properties of hot forged 18CrNiMo7-6 steel . ASM International - 29th Heat Treating Society Conference, HEAT TREAT 2017. 2017-October. p. 33-38.

Wear mechanism of Mo-W doped carbon-based coating during boundary lubricated sliding @inproceedings{458cbcaf07864e758e99ace1a7dc6037, title = "Wear mechanism of Mo-W doped carbon-based coating during boundary lubricated sliding", abstract = "The high temperature tribological applications of state-of-the-art diamond-like-carbon (DLC) coatings in automotive industry are often compromised due to their poor adhesion strength and low thermal stability. A molybdenum and tungsten doped carbon-based coating (Mo-W -C) is developed in order to overcome these limitations and to enhance tribological performance during boundary lubricated sliding at ambient and elevated temperature. The coating was deposited utilis-ing HIPIMS technology. MoW -C coating showed lowest mean friction coefficient (µ = 0.033) compared to a number of commercially available state-of-the-art DLC coatings when pin-on-disc experiments were carried out at ambient temperature. Similarly at 200°C, a significant reduction in friction coefficient was observed for MoW -C coating with increase in sliding distance unlike DLC coating. Raman spec-troscopy revealed importance of combined Mo and W doping and tribochemically reactive wear mechanism of MoW -C coating during sliding. The significant decrease in friction and wear rate was attributed to the presence of graphitic carbon particles (from coating) and 'in-situ' formed metal sulphides (WS 2 and MoS 2 , where metals from coating and sulphur from oil) in transfer layer. ", keywords = "diamond-like-carbon, carbon-based coating, boundary lubricated sliding, lubricant, tribology", author = "P. Mandal and A.P. Ehiasarian and P.Eh. Hovsepian", year = "2015", month = apr, day = "25", language = "English", pages = "1--6", booktitle = "58th Annual Technical Conference Proceedings", publisher = "Society of Vacuum Coaters", note = "Society of Vacuum Coaters Annual Technical Conference ; Conference date: 25-04-2015 Through 30-04-2015", } . 58th Annual Technical Conference Proceedings.

Sharp, J., Muller, I.C., Mandal, P., Abbas, A., West, G., Rainforth, W.M., Ehiasarian, A., Hovsepian, P.(2015). Cross sectional TEM analysis of duplex HIPIMS and DC magnetron sputtered Mo and W doped carbon coatings . Journal of Physics: Conference Series. 644. (1).

Effect of the degree of high power impulse magnetron sputtering (HIPIMS) utilisation on the corrosion properties of tin films @conference{2c776f8b54d3493182bf614dc5996274, title = "Effect of the degree of high power impulse magnetron sputtering (HIPIMS) utilisation on the corrosion properties of tin films", abstract = "TiN coatings were deposited by conventional dc unbalanced magnetron (UBM) sputtering, combined High Power Impulse Magnetron Sputtering (HIPIMS)/UBM and pure HIPIMS sources in an industrial size 4 cathode magnetron sputtering machine with a bias of -50V during deposition. Four source combinations were used namely 4UBM (pure UBM), 1HIPIMS+3UBM, 2HIPIMS+2UBM and 2 HIPIMS (pure HIPIMS) for the deposition. Optical emission spectroscopy (OES) measurements revealed that the degree of Ti ion flux increased with increasing number of HIPIMS sources involved in the process. The microstructural characterisation was done by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The potenitiodynamic polarization measurements showed that the pure HIPIMS and 2HIPIMS+2UBM exhibited better corrosion resistance compared to 1HIPIMS+3UBM and pure UBM coatings. The positive shift of Ecorr value from -391 mV for pure UBM coating to +305 mV for 2HIPIMS+2UBM coating was observed. The SEM investigations of corroded samples revealed that the pure UBM coating exhibited more number of corrosion pits which is a clear sign of aggressive corrosion than the other three coatings. Raman analysis showed that pure UBM and 1HIPIMS+3UBM coating corroded more and allowed the electrolyte to react with the substrate as oxides due to substrate contribution can be seen on the surface. Moreover 2HIPIMS+2UBM and pure HIPIMS coating surfaces were free from these oxides due to highly dense microstructure. The cross section TEM analysis exhibited the void free high density coating with weak column boundaries deposited by pure HIPIMS sources.", keywords = "TiN coatings, unbalanced magnetron, high power impulse magnetron sputtering, optical emission spectroscopy, corrosion resistance, metal nitride coatings, corrosion resistant thin films", author = "Sugumaran, {A. A.} and Y. Purandare and P. Mandal and A.P. Ehiasarian and I. Khan and P.Eh. Hovsepian", year = "2013", month = aug, day = "18", doi = "10.14332/svc13.proc.1039", language = "English", pages = "423--432", note = "56th Annual Technical Conference of the Society of Vacuum Coaters, SVC TECHCON 2013 ; Conference date: 20-04-2013 Through 25-04-2013", } . 56th Annual Technical Conference of the Society of Vacuum Coaters, Providence, RI, United States, 20/04/13.

DISSERTATION THESIS

Tribological study of novel metal-doped carbon-based coatings with enhanced thermal stability @phdthesis{4510c695e85a4abfb19dd35f43ae2e0e, title = "Tribological study of novel metal-doped carbon-based coatings with enhanced thermal stability", abstract = "Low energy consumption and reduced emission of greenhouse gases are two main challenges which trigger competitive growth of future automobiles. National Research Council, Washington DC (2011) on an assessment of fuel economy of light-duty vehicles reports that 21% of total fuel energy is spent to move the car and 17% to overcome frictional losses in engine parts. An attempt to curb these losses has already been commercially appreciated through the use of advanced surface engineering techniques on mating engine parts and new engine lubricants. In addition, friction effects wear and sometimes corrosion in these parts which recommends a robust system which would improve the tribological behaviour of surface engineered parts. Thus low friction and high temperature wear resistant coatings are in high demand for use on engine components. Diamond-like carbon (DLC) coatings are extensively used for this purpose due to their excellent tribological properties in presence of commercial lubricants. However, DLC coatings degrade at high temperature and pressure conditions leading to significant increase in friction and wear rate even in the presence of lubricant. This is a major concern of automobile manufacturers as the degradation is further aggravated by poor coating-substrate adhesion, finally delaminating the DLC coating from the base material. Hence to develop a thermally stable tribological coating with good adhesion quality for engine components, both the transitional metals Mo and W are simultaneously introduced in a carbon-based coating (Mo–W–C) for the first time utilising the benefits of smart material combination and High Power Impulse Magnetron Sputtering (HIPIMS).This research includes development of Mo–W–C coating and investigation of thermal stability and tribological properties at ambient and high temperatures. The as-deposited Mo–W–C coating contains nanocrystalline almost X-ray amorphous structure and show dense microstructure, good adhesion with substrate (Lc~80 N) and high hardness (~17 GPa). During boundary lubricated sliding (commercially available engine oil without friction modifier as lubricant) at ambient temperature, Mo–W–C coating outperforms commercially available state-of-the-art DLC coatings by providing significantly low friction (µ~0.03 – 0.05) and excellent wear resistance (no measurable wear). When lubricated sliding tests are carried out at 200°C, Mo–W–C coating provides low friction similar to ambient temperature, whereas degradation of DLC coating properties fails to maintain low friction coefficient. A range of surface analyses techniques reveal {"}in-situ{"} formation of solid lubricants (WS2 and MoS2) at the tribo-contacts due to tribochemically reactive wear mechanism at ambient and high temperature. Mo−W−C coating reacts with EP additives present in the engine oil during sliding to form WS2 and MoS2. This mechanism is believed to be the key-factor for low friction properties of Mo−W−C coating and presence of graphitic carbon particles further benefits the friction behaviour. It is observed that low friction is achieved mostly due to formation of WS2 at ambient temperature, whereas formation of both WS2 and MoS2 significantly decreases the friction of Mo–W–C coating at high temperature. This further indicates importance of combined Mo and W doping over single-metal doping into carbon-based coatings.Isothermal oxidation tests indicate that Mo–W–C coating preserves it's as-deposited graphitic nature up to 500°C, whereas local delamination of DLC coating leads to substrate exposure and loss of its diamond-like structure at the same temperature. Further, thermo-gravimetric tests confirm excellent thermal stability of Mo–W–C compared to DLC. Mo–W–C coating resists oxidation up to ~800°C and no coating delamination is observed due to retained coating integrity and its strong adhesion with substrate. On the other hand, state-of-the-art DLC coating starts to delaminate beyond ~380°C. The test results confirm that Mo–W–C coating sustains high working temperature and simultaneously maintains improved tribological properties during boundary lubricated condition at ambient and high temperature. Thus Mo–W–C coating is a suitable candidate for low friction and high temperature wear resistant applications compared to commercially available state-of-the-art DLC coatings.", keywords = "carbon-based coatings, thermal stability, metal-doped carbon-based coatings, tribological properties", author = "Paranjayee Mandal", year = "2015", language = "English", publisher = "Sheffield Hallam University", address = "United Kingdom", school = "Sheffield Hallam University", } .