Structure and Properties of Ti-Zr-Ni-Co-Cu High-Entropy Alloy After Powder Bed Fusion of Powders Produced by Mechanical Alloying and Plasma Spheroidization

摘要

In this paper, the Ti25Zr25Ni25Co10Cu15 high entropy alloy has been investigated. A novel approach to manufacture high-temperature shape memory alloys is proposed. A fundamental possibility to obtain compact samples by powder bed fusion using a laser beam (PBF-LB) from Ti25Zr25Ni25Co10Cu15 powder obtained by mechanical alloying and plasma spheroidization is shown. During PBF-LB, a mixed structure is formed. It consists of B2-TiNi-type austenite with Laves phases and zirconium oxides. The average grain size is around 5 mu m. The hardness of the alloy produced is more than 600 HV and significantly exceeds that of the alloy produced by conventional techniques. The ultimate compressive strength and the compressive yield strength of the samples are 640 MPa, and 600 MPa, respectively, meaning the synthesized samples are significantly inferior to the alloys produced by conventional smelting technologies. However, the ductility of 1.3 is comparable to that of similar alloys and indicates potential prospects of PBF-LB to manufacture Ti-Zr-Ni-Co-Cu HEAs.