Phase selection and mechanical properties of (Al21.7Cr15.8Fe28.6Ni33.9)x(Al9.4Cr19.7Fe41.4Ni29.5)100-x high entropy alloys

Abstract

In order to further understand the dependence between phase composition and alloying component. (Al21.7Cr15.8Fe28.6Ni33.9)x(Al9.4Cr19.7Fe41.4Ni29.5)100-x high entropy alloys (HEAs) are designed based on the AlCrFe2Ni2 eutectic high entropy alloy (EHEA). The phase composition, microstructure and mechanical properties of this HEA are investigated systematically. The result shows that the volume fraction of body-centered cubic (BCC) phase increases from 5.32% to 98.81% as the x value increasing. Compressive testing shows that the yield strength of (Al21.7Cr15.8Fe28.6Ni33.9)x(Al9.4Cr19.7Fe41.4Ni29.5)100-x HEAs boosts from 310 MPa to 1268 MPa, while the fracture strain gradually decreases from 55% (no fracture) to 33.85% with the development of x value. The accretion of BCC phase volume fraction is the main factor for increasing strength and decreasing fracture strain of alloy system. The valence electron concentration (VEC) is the fundamental parameter having affection on the phase selection of the alloy system, which was further verified by the calculation results of the physical parameters.