Effect of Annealing on Microstructure and Properties of AlCoCuFeTi High-Entropy Alloy Fabricated by Arc Melting

An AlCoCuFeTi high-entropy alloy with excellent wear resistance and high hardness was successfully produced by arc melting. The effects of annealing on the microstructure, nanomechanical behaviors, tribological properties, and corrosion resistance were systematically investigated. The results showed that the AlCoCuFeTi consisted of a Co-enriched L2 1 phase, a Cu-enriched FCC phase, and a (Fe, Ti)-enriched Laves phase. Annealing promoted the formation of FCC and Laves phases but decreased the volume fraction of the L2 1 phase. The high hardness of AlCoCuFeTi is attributed to the formation of L2 1 and Laves phases. The highest hardness (14.1 +/- 1.3 GPa) and reduced Young ' s modulus (256 +/- 11 GPa) were achieved in the 1100 degrees C annealed and 900 degrees C annealed specimens, respectively. All specimens exhibited excellent wear resistance compared to typical HEAs due to the mildoxidational wear mechanism. The 1100 degrees C annealed specimen possessed the highest elastic strain to failure (H/ E r ) and yield pressure (H 3 /E r 2 ), corresponding to its best-measured wear resistance. The segregation of Cu led to galvanic corrosion during the polarization tests, and the area ratio of cathode to anode (A c /A a ) determined the corrosion rate. The 1100 degrees C annealed specimen exhibited good corrosion resistance due to its low A c /A a value.