Aging behavior of a CuCr2Fe2NiMn high-entropy alloy

The effect of aging treatment on the hardness and microstructure of a CuCr2Fe2NiMn high-entropy alloy is investigated. The results show that the alloy exhibits a good high-temperature age hardening phenomenon and temper resistance. The aged alloy can obtain a peak hardness of 450 HV at 800 °C. Softening anneal occurs at 1100 °C. Age hardening is mainly attributed to the precipitation hardening of the ρ phase and a more homogeneous microstructure, whereas the softening of the aged alloy may be related to the decomposition of the ρ phase and Cu-rich FCC1 and to the coarsening of the FCC2 phase in the interdendrite regions.

Aging temperature has a significant effect on the microstructure of the CuCr2Fe2NiMn high-entropy alloy. As the temperature increased from 600 to 800 °C, the morphology of precipitates changes from rod-like to round particles with a size of 1–2 μm. These precipitates are identified as the ρ phase rich in Cr, Fe and Mn elements according to the EDS, which results in the age hardening. When the aging temperature increased to 1100 °C, the interdendrites are composed of (Cr, Fe, Ni)-rich FCC2 with a morphology of bulky strip or fine needle-like, which is responsible for the softening anneal at high temperature.Figure optionsDownload as PowerPoint slideHighlights
► CuCr2Fe2NiMn alloy exhibits a good high-temperature age hardening phenomenon.
► A peak hardness of Hv 450 at 800 °C was obtained due to the forming of ρ phase.
► Decomposition of ρ phase resulted in softening anneal at 1100 °C of aging.
► Good thermal stability gives it a potential for application in high temperature materials.