Effect of Friction Hardening on the Surface Mechanical Properties and Tribological Behavior of Biocompatible Ti-6Al-4V Alloy Publisher



Shahriyari F¹ ; Taghiabadi R¹ ; Razaghian A¹ ; Mahmoudi M² Show Affiliations
Source: Journal of Manufacturing Processes Published:2018

Abstract

The present study aimed at investigating the effects of friction hardening (FH) using a sliding 100 Cr6 steel indenter on the microstructure surface mechanical properties, and tribological behavior of Ti-6Al-4V alloy. The FH was performed under different traverse speeds (45, 90, 180, 360, 720, and 900 mm/min) for different number of passes (16, 30, 60, and 90 cycles) at the applied load of 700 N. The results demonstrated that the surface mechanical properties and sliding wear resistance of friction hardened samples improved mainly due to the intensive strain hardening, generation of ultrafine α-Ti grains, and fine distribution of β-phase particles at near-surface layers. At high traverse speeds (more than 720 mm/min), the friction hardening also leads to the formation of hard stress-induced α′-martensite phase in the surface microstructure which further improves the surface mechanical properties, but impairs the sliding wear resistance. SEM examination of worn surfaces and wear debris revealed that the predominant wear mechanisms in the annealed sample are severe abrasion (ploughing) and delamination of the tribolayer along with the generation of metallic wear particles. But, the wear mechanisms in the friction-hardened samples are mild abrasion and delamination of the tribolayer. The formation of α′-martensite during the FH process, however, encourages micro-cracking and spalling of the tribolayer leading to a slight growth in the wear. © 2017