Microstructural Characteristics and Wear Behavior of Sintered Ni-Modified Ti–xTiB₂ Composites

Titanium matrix composites were manufactured using pulsed plasma sintering with the addition of 5 wt.% Ni and TiB₂ (x = 5, 10, 15, 20 wt.%) particles at a sintering temperature of 1000 °C, a heating rate of 100 °C/min, and a holding time (300 s) at an applied pressure of 50 MPa. The study examines the densification, phase evolution, hardness, microstructure, and wear behavior of Ti–Ni alloys with different ceramic (TiB₂) contents. The results show that increasing TiB₂ content decreases relative density from 99 to 97% while increasing hardness from 229 to 586 HV_0.1. The addition of Ni particles resulted in laminar α-Ti with well-defined β-Ti grain boundaries. Furthermore, the microstructural studies have revealed a dual-phase beta and alpha Ti phase with uniformly dispersed TiB₂ content. As a result of the interactions between β-Ti and Ni during sintering, an intermetallic (Ti₂Ni) eutectoid phase was formed. The presence of Ni and TiB₂ particles reduces the average coefficient of friction, wear volume, and wear rate. Therefore, the reinforced titanium matrix composites wear track surfaces exhibited a combination of abrasive and adhesive wear modes.