Regular Article

Interfacial behaviour of the high-entropy alloy CuCoCrFeNi and TC4 joint obtained by vacuum diffusion welding

¹ School of New Energy and Materials, Southwest Petroleum University, Chengdu, 610500, PR China
² College of Materials Science and Engineering, Chongqing University, Chongqing, 400044, PR China

^* e-mail: zhangxj701@163.com

Received: 21 March 2022
Accepted: 15 June 2022

Abstract

In this work, good bonding between the high-entropy alloy (HEA) CuCoCrFeNi and TC4 titanium alloy was obtained through vacuum diffusion welding at a joining temperature of 1000  °C for 60 min under a pressure of 5 MPa. The results showed that the typical interfacial microstructure of the CuCoCrFeNi/TC4 joint was TC4/diffusion layer/island structure/dendritic structure/diffusion layer/HEA. Compared with Ti atoms, atoms such as Cr and Co from the CuCoCrFeNi substrate were prone to diffuse into the other material. Intermetallic compounds Cu_0.5Fe_0.5Ti and Co_0.15Ni_0.85Ti, solid solutions Ti(Fe, Cr)ss and amorphous materials were produced in the joint. The self-diffusion activation energy formula $Q=18R{T}_{melt}\approx 15.2\mathrm{\Delta }{H}_{melt}$ can be used to approximate the order of diffusion capacity of elements, which follows in Cr >Fe> Co > Ni.