High-throughput experimental study on the microstructural and compositional variations of mechanical properties for AlCoCrFeNi high entropy alloys

Abstract

To efficiently establish the relationship among microstructure, composition and mechanical properties of the AlCoCrFeNi high entropy alloys, a high-throughput experimental method has been developed combining diffusion couple with the nanoindentation technique. In this paper, B2(A2) denotes that A2 (disordered bcc) particles are coherently dispersed in the B2 (ordered bcc) matrix, and vice versa for A2(B2). A B2(A2)-A2(B2)-fcc sandwich microstructure was produced by annealing an Al1.1CoCrFeNi/CoCrFeNi diffusion couple. The following nanoindentation measurements found that the hardness of the A2(B2) structure is slightly lower than that of B2(A2), but the elastic modulus and ductility behave differently. The fcc region, on the other hand, has a larger ductility than both B2(A2) and A2(B2). In addition, the elastic modulus of fcc decreases with the increasing Al content, whereas the hardness does not significantly change with composition.