Friction and wear behavior of titanium matrix (TiB + TiC) composites

Titanium matrix composites (TMCs) have several attractive characteristics including high temperature properties, wear resistance and oxidation resistance. In the case of metal matrix composites, it is generally desirable to select reinforcements that exhibit suitable interfaces with the matrix, high temperature stability, and similar coefficients of thermal expansion with respect to the matrix. Conventional candidates for reinforcements in TMCs include SiC, Si3N4, Al2O3, TiC, TiN, TiB, and TiB2. These materials have high temperature properties, fatigue strength, and wear and oxidation resistance. TMC manufacturing methods can be divided into powder metallurgy and the melting route approach. In the case of powder metallurgy, the processing steps are very complicated, and an agglomeration of reinforcements can cause the deterioration of mechanical properties. In the melting route approach, net-shape forming is hard to obtain due to a high affinity in the molten state, and low fluidity of the melts. However, the melting route approach can provide an economical and sound final casting. In this study, we used the investment casting process for economical considerations. In addition, an in situ synthesis method was also developed to ensure homogeneous distribution and a controlled interfacial reaction between the matrix and reinforcements. The friction and wear behavior of TMCs were investigated using a pin-on-disk wear tester under various conditions and were evaluated using scanning electron microscopy (SEM) analysis.