Component and mechanical properties of the reaction layer of electron beam welded Re/GH3128

In this study,the Re/GH3128 were welded by electron beam and the reaction layer was found in welded joint. The focus was on the composition and mechanical properties of the reaction layer in order to clarify the reasons for the weak mechanical properties of it. The results show that reaction layer evolves from the top to the bottom through a band to a sawtooth shape,and its thickness tends to decrease due to the decrease of the melting of Re. The reaction layer plays a transforming role in the solidification of the weld in terms of composition,and also affects the solidification process of the weld. As for the mechanical properties: Horizontally (at the same welding depth),because of the difference in the content of alloy phase containing Re,the rate of variation of the plasticity index of the reaction layer tends to increase with decreasing distance from Re, and the plasticity index reaches a minimum near the fracture surface. Longitudinally (3 μm from Re), the mechanical properties of the reaction layer are not uniform.Due to the high Ni and Re content causing a better solid solution effect, the middle reaction layer has a better elastic modulus, nanohardness and elastic work index. •The effect of the reaction layer on the solidification of the weld in its nearby region is explained in terms of both composition and crystalline morphology.•Depending on the weld depth, a connection was found among the composition of the reaction layer, the fracture morphology of the joint, and the mechanical properties of the reaction layer.•By analyzing the microscopic mechanical properties of the reaction layer, the reasons for its weak mechanical properties were derived as follows. 1. The reaction layer near Re contains more rhenium-containing alloy phases. 2. unequal mechanical properties of the reaction layer at different weld depths.