The strengthening effects of relatively lightweight AlCoCrFeNi high entropy alloy.

In this paper, relatively lightweight AlCoCrFeNi HEA ingots with different initial microstructures were fabricated by utilizing the cooling rate effect. The associated mechanical properties and strengthening response are also reported. The body-centered cubic (BCC) AlCoCrFeNi HEAs solidified dendritically, and the dendrite (DR) regions were surrounded by the inter-dendrite (ID) regions. The volume fraction of the DR regions of the alloy formed via arc-melting was higher than those of their counterparts produced via levitation melting, which is considered to have a strong dependence on the cooling rate effect. In addition, the compressive properties were significantly influenced by the ratio of volume fraction of ID and DR regions, as well as the morphologies of the disordered body-centered cubic (A2) and ordered body-centered cubic (B2) phases. The alloy formulated via levitation melting exhibited higher hardness and compressive yield strength (YS) than the arc-melting alloy, at the expense of plasticity. The strengthening effects including grain boundary strengthening, dislocation strengthening, solid solution strengthening, and precipitation strengthening were estimated and compared with the experimental measurements. • The AlCoCrFeNi HEA ingots with different microstructure were designed and fabricated. • Microstructure and mechanical properties evolution with cooling rate were analyzed. • The strengthening mechanisms were estimated and compared with the experimental value. [ABSTRACT FROM AUTHOR]