Microstructure and Mechanical Properties of Ti/Cu/Fe Dissimilar Joints

• DOI: 10.1007/s11665-022-07445-5
• Publication Date: 2022-09-28T19:02:37Z
• Authors: Qiaoling Chu; Yi Li; Qilu Cao; Min Zhang; Jihong Li; Pengkang Zhao; Fuxue Yan; Hailong Luo; Xudong Wang; Cheng Yan
• Keywords: mechanical property; Ti/Cu/Fe trimetallic plate; 0203 mechanical engineering; microstructure; intermetallics; 02 engineering and technology; 620

The weldability of Ti/Cu/Fe trimetallic butt welds explosively bonded was investigated using the samples of different groove dimensions. The results indicated that the Ti/Cu dissimilar welds are free from cracks, and similar phase constituents are observed at Ti weld metal/Cu base metal interfaces. Cu 4 Ti intermetallics are formed adjacent to the Cu matrix (Cu weld metal/base metal). CuTi intermetallics with columnar structure is perpendicular to the interface and grow into the Ti weld metal. CuTi 2 intermetallics show wide distribution with different morphology. Severe cracks are observed at Cu weld metal/Fe weld metal interface, attributed to the significant difference in melting point and low mutual solid solution between Fe and Cu alloys. During the solidification, it is found that liquid Cu penetrates into and weakens Fe grain boundaries. Ti weld metal near Cu matrix has a high microhardness (340 ~ 420 HV0.1). The fractography of the tensile sample confirms the quasi-cleavage fracture at Ti weld metal/Cu weld metal interface and intergranular fracture in the Fe weld metal. Possible ways to improve the welding process are also proposed.