Work

Microstructural features and mechanical properties of in-situ remelting welding of TC4 titanium alloy and T2 copper welded joint by electron beam

Year: 2024

Type: article

Abstract: In order to achieve high-quality welding of titanium copper dissimilar metals, the in-situ remelting welded joints of TC4 and T2 were obtained by using a time-sharing dual electron beam(TDEB). A welded joint consisting of the IMCs layer, FZ zone, copper weld zone, and titanium side HAZ is formed in the TC4/T2 interface area. The microstructure and morphology of IMCs layers in welded joints with TDEB welding and copper offset welding were observed by using SEM and TEM . Multiple forms of IMCs were observed in the IMCs layer, including columnar Ti2Cu, granular Ti3Cu4, and sheet-like TiCu4, clarifying the orientation relationship between some precipitates and matrix phases . The TC4/T2 joint welded with TDEB welding achieved micro zone remelting of the IMCs layer. The thickness of the IMCs layer has significantly decreased, and the number of copper-rich phases in the IMCs layer has increased, which improves the mechanical properties of the welded joint. The TC4/T2 joint welded by time-sharing dual beam electron beam has a tensile strength of 215.9 MPa and an elongation of 6.14%. The joint exhibits brittle quasi dissociation fracture. The main factor causing fracture is the high brittleness and hardness of titanium-rich phases such as TiCu and Ti2Cu. This study provide a new welding method for titanium copper dissimilar metals, as well as research ideas for dissimilar metal welding .

Source: Journal of Materials Research and Technology

DOI: 10.1016/j.jmrt.2024.11.062