Tensile properties and strengthening behavior of CoCrFeNiW high entropy alloys with heterogeneous structures
Co30Cr30(FeNi)40-xWx(x=0-8 at.％,simplified as HW0-HW8,respectively)high entropy alloys(HEAs)were fabricated by vacuum arc-melting.The microstructure and tensile properties of as-cast and as-annealed alloys were investigated.The results show that HW2 and HW4 have a single FCC phase.The fine and granular μ phase is dispersed in FCC matrix and the area fraction increases with the increase of W content and annealing temperature.The soft FCC matrix and hard μ phase constitute the hetero structure with strain incompatibility.With the increase of W content from 0 to 8 at.％,the yield strength and tensile strength increase from 278 and 629 MPato 530 and 839 MPa,respectively.The strain maintains 33％.The as-annealed HW8 exhibits superior yield strength(810 MPa)and tensile strength(1087 MPa).The yield strength improvement is attributed to solid-solution,precipitate,and back stress strengthening.Back stress strengthening plays a dominant role in improving tensile strength and plasticity by inducing high hardening behavior in heterogeneous structures.
high entropy alloyheterogeneous structuretensile propertiesstrain hardeningstrengthening mechanism
万方数据
维普
