Microstructure, Mechanical, and Damping Properties of Ti2V3NbMn4Cu4 High-Entropy Alloy Matrix Composites

In this paper, nano-C reinforced Ti2V3NbMn4Cu4 high-entropy alloy (HEA) matrix composites were prepared by powder metallurgy. The microstructure of the composites was analyzed, and the mechanical properties and damping properties were tested. The gamma-MnCu phase with face-centered cubic (FCC) structure was distributed in the HEA and twins were observed. The compressive strength and strain of the HEA were 1158 MPa and 21.5%, respectively. The good ductility was related to the FCC phase. The hardness and strength of the composites are higher, and the strengthening mechanism is mainly load transferring and dispersion strengthening. The internal friction increases with the increase of strain amplitude, and Q(max)(-1) of the HEA was 0.022. The internal friction curves of the HEA with temperature were tested. The Q(-1) was always greater than 0.01. The damping mechanism was mainly related to twins induced by the anti-ferromagnetic sequence transition and the martensitic transformation of gamma-MnCu phase. Therefore, FCC phase is the key to the strength and toughness synergy and high damping properties of the Ti2V3NbMn4Cu4 HEA.