Class I type creep behavior of coarse-grained Al0.5CoCrFeMnNi high entropy alloy

The high-temperature deformation behavior of homogenized cast Al0.5CoCrFeMnNi with a coarse-grained face centered cubic (FCC) phase and a small amount of body centered cubic phase-dispersed within the FCC matrix grains was investigated using tensile creep and elongation tests at three temperatures of 1023, 1098 and 1173 K in a wide strain rate range between 10(-8) and 10(-1) s(-1). As the strain rate increased, the strain rate regime associated with n = 3 (where n is the stress exponent) and n = 5 and power law breakdown (n > 7) appeared in sequence. As the temperature increased, the upper limit of the strain rate for n = 3 increased. The inverse primary creep behavior occurred and subgrain formation was not observed at the low strain rates and high temperatures associated with n = 3, strongly suggesting that solute drag creep is the rate-controlling deformation mechanism. Furthermore, the deformation mechanism of Al0.5CoCrFeMnNi was very similar to that of binary Al-Mg alloys known as typical class I solid solution alloys. The concept of breakaway stress from solute atmosphere could explain the transition of deformation mechanism from solute drag creep to dislocation climb creep at high strain rates.

Automated summary

The high-temperature deformation behavior of homogenized cast Al0.5CoCrFeMnNi alloy was studied, revealing different deformation mechanisms at different temperatures and strain rates, with solute drag creep being the dominant mechanism at low temperatures and low strain rates.