Influence of bulk post processing techniques on anisotropy of microstructural and tribological properties of L-DED produced Ti64 alloy

Abstract

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 Al<inf>2</inf>O<inf>3</inf> 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.