A novel dual phase high entropy casting alloy with high damping capacity

Abstract

The microstructure, phase structure, mechanical properties and damping capacity of Al _x Fe _2 CrNiCu ( x = 0.0, 0.5, 0.75, 1.0, 1.5) (x in molar ratio) HEAs were investigated. The results show that with the increase of x value, the volume fractions of BCC phase increase from 0 for x = 0.0 to 100% x = 1.5 for the as-cast Al _x Fe _2 CrNiCu HEAs. Among them, a novel dual phase microstructure consisting of 51 vol.% FCC and 49 vol.% BCC with large interface area was obtained in Al _0.5 FeCrNiCu HEA. Especially the compressive yield strength of the alloy with BCC structure is more than 5 times larger than that of the alloy with FCC structure, indicating that a typical damping alloy with a soft second phase distributed on the hard matrix was successfully fabricated. Compared with other HEAs, the damping capacity (Q ^−1 ) of Al _0.5 HEA is 0.1, which is the largest one obtained up to now. The foundational contribution of this paper is to show that the damping capacity of the HEAs can be adjusted by tuning the volume fraction of BCC and FCC phases.

Keywords

• high entropy alloys
• microstructure
• phase selection
• damping capacity
• alloy design