Microstructures and Mechanical Properties of Age Hardenable Cu-2.0wt%Be Alloy for Projection Welding Electrode

Abstract

Evaluations of the microstructure and mechanical properties of age hardenable Cu-2.0wt%Be alloy are performed in order to determine whether it can be used as a welding electrode for projection welding. The microstructure examinations, hardness measurements, and tensile tests of selective aging conditions are conducted. The results indicate that the aging treatment with the fine-grained microstructure exhibits better hardness and high tensile properties than those of the coarsegrained microstructure. The highest hardness value and high tensile strength are obtained from the aged condition of 300 o C for 360 min due to the presence of the metastable γ . precipitates on the grain boundaries. The values of the highest hardness and tensile strength are measured as 374 Hv and 1236.2 MPa, respectively. The metastable γ . precipitates are transferred to the equilibrium γ precipitates due to the over-aged treatment. The presence of the γ precipitates appears as nodule-like precipitates decorated around the grain boundaries. The welding electrode with the best aging treated condition exhibits better welding performance for electrodes than those of electrodes used previously.