LOW TEMPERATURE MECHANICAL BEHAVIOR OF THE Al_(0, 5)CoCrCuFeNi HIGH-ENTROPY ALLOY

摘要

High-entropy alloy Al_(0, 5)CoCrCuFeNi prepared by arc-melting its components in the purified argon atmosphere has been deformed by compression and the peculiarities of the plastic deformation have been studied for the first time at temperature ranging from 300 K to 4, 2 K. The alloy has been found to provide a high strength and plasticity greater than 30 % in this temperature range: the yield stress amounts to 450 MPa for 300 K and 750 MPa for 4,2 K. At the temperatures below 15 K the smooth behavior of the stress-strain curves changes to the jumplike one. In the temperature range 300 K - 30 K at the onset of deformation curves (ε~2 %) the strain rate sensitivity has been determined by means of the strain rate cycling method. Under the assumption of thermally activated plastic deformation behavior, the activation volume values have been calculated for the thermally activated dislocations movement. The values were found to vary from 81.b~3 at 300 K to 23.b~3 at 30 K.