A Comparison of Microstructure, Hardness, and Wear Behavior of Ti matrix Composites Reinforced with in-Situ Reinforcements Synthesized Using TiB۲ and B۴C

Pressureless sintering was employed at ۱۴۰۰ °C to synthesize Ti matrix composites (TMCs) reinforced with in-situ TiB and TiC reinforcements using TiB۲ and B۴C initial reinforcements. The microstructure and wear behavior of the synthesized composites were evaluated and compared and the results showed that B۴C caused the formation of TiB-TiC in-situ hybrid reinforcements in the Ti matrix. Also, TiB was in the form of blades/needles and whiskers, and TiC was almost equiaxed. Moreover, the volume fraction of the in-situ formed reinforcement using B۴C was much higher than that formed using TiB۲. In addition, although the hardness of the B۴C-synthesized composites was higher, the composite synthesized using ۳ wt.% TiB۲ exhibited the highest hardness (۴۲۵ HV). The wear test results showed that the sample synthesized using ۳ wt.% TiB۲ showed the lowest wear rate at ۵۰ N, mainly because of its higher hardness. The dominant wear mechanism in the samples synthesized using ۳ wt.% B۴C was abrasive and delamination at ۵۰ N and ۱۰۰ N, respectively while in the samples synthesized ۳ wt.% TiB۲, a combination of delamination and adhesive wear and adhesive wear was ruling, respectively.

کلیدواژه ها:

Pressureless sintering ، Titanium ، Composite ، Microstructure ، Wear