Alcocrfeni-Niti High Entropy Alloy Composites : Microstructure and Wear Performance

In the current research, AlCoCrFeNi–x wt.% NiTi (x= 0, 5, and 10) composites were prepared using a combination of mechanical alloying (MA) and spark plasma sintering (SPS) methods. Microstructural studies showed that the introduction of 5 wt.% NiTi slightly changed BCC and FCC contents of the high entropy alloy (HEA) matrix. However, in HEA-10NiTi sample, with the increasing of interfacial regions and acceleration of interdiffusion between elements, (Ni,Al)-rich BCC phase content was considerably reduced. According to nanoindentation tests, NiTi and BCC phases possess higher hardness to elastic modulus (H/E) values that confirm the constructive effect of these two phases on the tribological behavior. Among the prepared specimens, HEA-5NiTi had the lowest wear rate (0.71 ± 0.01 mm3/N.m) which can be attributed to the higher weight percentage of BCC phase and the reinforcing effect of NiTi particles