Titanium carbide (TiC) dispersed surface on titanium based alloy (Ti-13Nb-13Zr) by in-situ laser composite surfacing and its wear performance

Abstract

Ti-13Nb-13Zr is a promising titanium-based alloy for bioimplant applications due to its low Young’s modulus (80 GPa). However, it undergoes mechanical and mechano-chemical degradation after long-term application in the human body. The present study concerns the development of TiC dispersed surface on Ti-13Nb-13Zr by preplacement of graphite and subsequent melting with a continuous wave (CW) fiber-coupled diode laser using varied power (1000 W to 1400 W) and scan speed (10 mm/s to 20 mm/s). Laser composite surfacing leads to the formation of dispersion of carbide (TiC) in the beta (β) matrix. There is an improvement in microhardness from 257 VHN (for as-received) to 360–519 VHN for laser composite surfaced Ti-13Nb-13Zr and varied with process parameters. There is an increase in nanohardness value from 3.6 GPa (for as-received Ti-13Nb-13Zr) to 5.14–9.224 GPa and increased in Young’s modulus from 100 MPa (for as-received Ti-13Nb-13Zr) to 103.22–120.85 MPa due to laser composite surfacing. A significant improvement in wear resistance (5.8 times) and a decrease in coefficient of friction (COF) (2.8 times) against the WC ball in fretting wear mode was noticed. The wear mechanism has been schematically presented and discussed in details.