Serration behavior and microstructure of high entropy alloy CoCrFeMnNi prepared by powder metallurgy

The equiatomic CoCrFeMnNi high entropy alloy prepared by powder metallurgy has homogenous chemical composition and microstructure. The mechanical properties of the CoCrFeMnNi high entropy alloy at the strain rates (1 × 10−4 s−1 to 0.1 s−1 and 1 × 103 s−1 to 3 × 103 s−1) and the temperature (298 K, 673 K and 1073 K) were investigated. Results indicate that the yield strength of the CoCrFeMnNi high entropy alloy is in the range of 350-700 MPa, increasing sensitively with increasing the strain rates, especially at a high strain rate (larger than 1 × 103 s−1). The serration behavior of the high entropy alloy is observed on the flow stress curves of the alloy deformed at a low strain rate of 1 × 10−3 s−1 and the high strain rates (1 × 103 s−1 to 3 × 103 s−1). Influences of the strain rate and the temperature on the serration behavior of the CoCrFeMnNi high entropy alloy are discussed.