Study on the effect of heat treatment on the microstructure and properties of C17300 beryllium copper alloy microwires

The effects of solution time and aging temperature on the microstructure and properties of C17300 beryllium copper alloy wire were studied by means of SEM, XRD, electronic universal tester and resistance tester. The results show that after solution treatment, the deformed twin structure disappears and the distorted crystal grows into equiaxed crystal. The optimum solution time is 90min, and the hardness and resistivity are 115HV and 1.13×10-7Ω·m respectively. The optimum solution time is 90min, and the hardness and resistivity are 115HV and 9.52×10-7Ω·m respectively. When the aging temperature is increased from 260°C to 340°C, the amount of grain boundary reaction is increased from 3.84% to 17.05%, and the precipitated phase changes from point to tumor-like distribution. When the aging temperature rises to 320°C, the mechanical properties are the best, with tensile strength of 1192.86MPa, hardness of 373.81HV and elongation of 5.16%. With the increase of aging temperature, the work hardening rate gradually increases, the number of dimples and micropores on the fracture surface decreases, and the granular precipitates at the bottom of dimples increase. In summary, the differences of microstructure and mechanical properties of beryllium bronze at different solution time and aging temperature are compared, which provides some basis for preparing high strength beryllium copper alloy microwires.