Enhanced wear resistance of TiC/Ti6Al4V composites through changing TiC morphologies in laser direct energy deposition

Abstract

The wear performance of particle-reinforced metal matrix composites is significantly influenced by the morphologies of ceramic particles. In this study, the friction and wear characterization of titanium matrix composites (TMCs) with different TiC morphologies was studied. This TMCs, consisting of 20 wt% of TiC, was prepared by laser direct energy deposition (LDED). Different LDED parameters are employed to changing the morphologies of TiC. Two distinct TiC morphologies, equiaxed and dendritic, are achieved by varying the laser scanning speed and laser power during the LDEDed TMCs. The friction and wear tests of TMCs with different TiC morphologies are carried out by using a ball-on flat reciprocating tribometer. The results reveal that TMCs with different TiC morphologies manifest divergent wear mechanisms. TMCs with equiaxed TiC dominates three-body wear due to the fracture debonding and pulling out of TiC, resulting in a higher wear rate. TMCs with dendritic TiC mainly dominates two-body wear, facilitated by the protection of hard dendrites and the tribolayer, which leads to a 59% improvement in wear resistance compared to TMCs with equiaxed TiC. This work provides a method of TiC morphologies changing to achieve an enhanced wear performance for TMCs.