Browsing by Author "Kuriachen, B."

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Influence of bulk post processing techniques on anisotropy of microstructural and tribological properties of L-DED produced Ti64 alloy
(Elsevier Ltd, 2025) Suresh, S.; Joshy, J.; Kuriachen, B.; Gurugubelli, R.C.; Kumar, V.; Bontha, S.
Laser-Direct Energy Deposited (L-DED) Ti64 alloy is known to have high anisotropy, and low wear resistance which reduce the longevity of artificial bone joints. Thus, the primary objective of this study is to compare and contrast the effect of bulk treatments to mitigate these inherent limitations. Keeping printing parameters constant, the printed samples were put through different post-treatments, namely, super-? annealing (1050 °C, 1 h) and deep cryogenic dipping (?196 °C, 48 h). Electron back scatter diffraction (EBSD) and x-ray diffraction (XRD) analysis revealed differences in grain morphology and phase distributions in the treated samples. A linear reciprocating wear test is conducted with Al2O3 as the counter body to mimic the artificial hip socket. The super-? annealing process reduced the anisotropy in wear rate from 76 % to 60 % but did not show an overall betterment. On the other hand, the cryo-treatment showed an 83 % reduction in wear and a slight reduction in anisotropy compared to the as-build sample. The coefficient of friction (COF) plots also displayed an increase for annealed samples (15.4%–31.5 % higher) while showing a major reduction in cryo-treated samples (42.8%–54.7 % reduction). © 2025 Elsevier B.V.
Influence of Process Parameters on Microstructural Properties of L-DED Produced Ti64 Alloy
(Springer Science and Business Media Deutschland GmbH, 2025) Suresh, S.; Kuriachen, B.; Kumar, V.; Bontha, S.; Gurugubelli, R.C.
Additive manufacturing (AM) techniques have revolutionized the manufacturing of complex and customized parts across various applications. However, they are known for producing titanium parts with high anisotropy and low ductility, due to high cooling gradient in the build direction and the presence of martensite phase in microstructure respectively. These are inherent problems which limit their application in critical engineering fields. Laserâ€”Direct Energy Deposition (L-DED) produced parts also have the same disadvantages. Thus, the primary objective of this paper is to identify the optimal combination of process parameters for L-DED that can mitigate these inherent limitations. Keeping the parameters such as powder size, orientation angle and hatch angle as constant, the laser power and scan speed are varied to fabricate 9 different sets of samples using L-DED. The research methodology includes an analysis of the microstructure, focusing on grain width, phase distribution, lath characteristics and presence of defects, if any. Microscopy and XRD techniques were used to observe the microstructure. Additionally, hardness studies were performed to evaluate the changes in material hardness. It was noticed thatÂ laser power significantly influences Î² width and Î±â€™ length while scan speed has a lesser dominant effect on both of them. The findings will contribute to the development of process-structure-property relations for L-DED-produced Ti64 and further, optimized manufacturing strategies for producing titanium parts with reduced anisotropy and increased ductility. Â© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.
Influence of weld parameters on the tribocorrosion behaviour of friction stir welded AA5052 in the marine environment
(Elsevier Ltd, 2025) Anantharam, G.S.; Bhole, K.B.; Kuriachen, B.; Arya, S.B.
The study involves tribocorrosive investigation of FSW-AA5052 formed at tool-speeds of 800, 1000, and 1200 rpm and welding-speeds of 60, 80, and 100 mm/min, for which Pin-on-disc tests in conjunction with open-circuit-potential and potentiodynamic-polarization techniques were utilised. For microstructures EBSD, Optical images and XRD were taken. Results revealed that cast (?1.212 V; 332.43 ?m/year), 800 rpm (?1.213 V; 433.51 ?m/year) and 1000 rpm (-1.236 V; 227.45?m/year) welded samples showed better performance than all the 1200 rpm welded samples. Frictional characteristics of 800 rpm (CoF-1.28) and 1000 rpm (CoF-1.32) samples were better than other samples due to uniform and stable passivation. Elemental analysis showed Oxides and Chlorides of Al and Mg formed over the worn surfaces. © 2025 Elsevier Ltd
Multi Response Optimization and Experimental Investigations into the Impact of Wire EDM on the Tribological Properties of Ti 6Al 4V
(2018) Kuriachen, B.; Lijesh, K.P.; Kuppan, P.
Titanium (Ti) alloy, Ti 6Al 4V (commonly known as Ti64), is employed in numerous applications due to their superior strength to weight ratio, low cost to performance ratio, tensile strength, and corrosion resistance properties. However, due to its poor tribological (friction and wear) properties and difficult-to-machine material, its implementation in the intended applications is limited. Nevertheless, Ti64 can be accurately machined using wire electrical discharge machining (WEDM) and further, this process develops a recast layer on the surface of Ti64, which posses larger percentage of oxygen. Therefore, in the present work, it is hypothesized that, the presence of the recast layer on the surface of Ti64 may enhance its tribological properties. To validate the proposed hypothesis, pins of (1) pure Ti64 and (2) WEDMed Ti64 were slided against EN32 steel disc on a pin on disc experimental setup for load of 50 N, rotational speed of 200 rpm and sliding distance of 500 m. In-situ analysis (scanning electron microscope and energy dispersive spectroscopy) and mechanical properties (nano-hardness and elastic modulus) were performed on the pin s surface, to identify the change in properties. Obtained results indicated significant increase in the oxide layer formation, consequently enhanced the tribological properties of WEDMed Ti64 compared to pure Ti64. To understand the tribological behavior of WEDMed Ti64 at other rotational speed and load, second set of experiments was performed by varying load (50, 70 and 90 N) and rotational speed of (200, 400 and 600 rpm). It was observed that wear values were not proportional to increase in load and speed. To identify the condition favoring the tribological behavior, multi-response optimization technique was performed and the identified load and speed values for the optimum tribological behavior were estimated. 2018, The Indian Institute of Metals - IIM.
Multi Response Optimization and Experimental Investigations into the Impact of Wire EDM on the Tribological Properties of Ti–6Al–4V
(Springer India, 2018) Kuriachen, B.; Lijesh, L.; Kuppan, P.
Titanium (Ti) alloy, Ti–6Al–4V (commonly known as Ti64), is employed in numerous applications due to their superior strength to weight ratio, low cost to performance ratio, tensile strength, and corrosion resistance properties. However, due to its poor tribological (friction and wear) properties and difficult-to-machine material, its implementation in the intended applications is limited. Nevertheless, Ti64 can be accurately machined using wire electrical discharge machining (WEDM) and further, this process develops a recast layer on the surface of Ti64, which posses larger percentage of oxygen. Therefore, in the present work, it is hypothesized that, the presence of the recast layer on the surface of Ti64 may enhance its tribological properties. To validate the proposed hypothesis, pins of (1) pure Ti64 and (2) WEDMed Ti64 were slided against EN32 steel disc on a pin on disc experimental setup for load of 50 N, rotational speed of 200 rpm and sliding distance of 500 m. In-situ analysis (scanning electron microscope and energy dispersive spectroscopy) and mechanical properties (nano-hardness and elastic modulus) were performed on the pin’s surface, to identify the change in properties. Obtained results indicated significant increase in the oxide layer formation, consequently enhanced the tribological properties of WEDMed Ti64 compared to pure Ti64. To understand the tribological behavior of WEDMed Ti64 at other rotational speed and load, second set of experiments was performed by varying load (50, 70 and 90 N) and rotational speed of (200, 400 and 600 rpm). It was observed that wear values were not proportional to increase in load and speed. To identify the condition favoring the tribological behavior, multi-response optimization technique was performed and the identified load and speed values for the optimum tribological behavior were estimated. © 2018, The Indian Institute of Metals - IIM.