Effect of Deformation Temperatures on the Microstructure and Mechanical Properties of a Non-isoatomic AlCoFeMnNi High-Entropy Alloy

The deformation behavior of non-isoatomic AlCoFeMnNi high entropy alloy after tensile deformation at room temperature and -196 ℃ is studied. Compared with room temperature, the strength of the alloy increases from 750 MPa to 1102 MPa at −196 ℃, the tensile strength increases from 1168 MPa to 1502 MPa, but the elongation decreases from 19.6% to 15.2%. The increase in the strength of is attributed to the low temperature inhibiting the dislocation movement, resulting in dislocation slip requiring high shear stress. As the temperature decreases, cross-slip decreases, which makes it difficult for the dislocation to transfer to another slip plane through cross-slip after pile-up, and can only form a planar piled-up group, resulting in local stress concentration and premature failure of the material.