Explosive welding and performance test of Al_0.1CoCrFeNi high-entropy alloy/TA2 composite plate

High-entropy alloy (HEA) is an emerging material which possesses great potential as a structure material, but there are relatively few studies devoted to HEA joining technology. The TA2 commercial pure titanium plate and Al_0.1CoCrFeNi HEA are joined by explosive welding technology. The microstructure analysis and mechanical tests of Al_0.1CoCrFeNi/TA2 composite plate are conducted. These results show that the Al_0.1CoCrFeNi/TA2 composite plate possesses a wavy bonding interface with a discontinuous melted zone. Moreover, the melted zone presents a multi-element mixed state, and a relatively uniform element distribution occurs in the melted zone. The hardness of the melting zone is greater than that of TA2 side and Al_0.1CoCrFeNi HEA side. And it gradually decreases with the increase of the distance from the interface. However, the hardness of the composite plate is still higher than that of the parent materials. Compared with the strength of the Al_0.1CoCrFeNi HEA plate (398 MPa), the strength of the Al_0.1CoCrFeNi/TA2 composite plate after explosive welding is significantly increased (567 MPa). On the contrary, elongation is reduced after explosive welding. The results tests show that explosive welding is an effective method for joining TA2 commercial pure titanium with Al_0.1CoCrFeNi high-entropy alloy, and the welded composite plate shows great mechanical performance.