Dynamic Tensile Properties and Deformational Mechanism of C5191 Phosphor Bronze

To observe the dynamic mechanical response and investigate the processes of high speed stamping for C5191 phosphorus bronze, tensile tests of C5191 phosphor bronze under quasi-static tensile condition at a strain rate of 0.001 s−1 by electronic universal testing machine, and dynamic tensile tests at strain rates of 500, 1000 and 1500 s−1 by split Hopkinson tensile bar (SHTB) apparatus were performed. The dynamic tensile properties and deformational mechanism were investigated by SEM and TEM. The results show that the yield strength and tensile strength of C5191 phosphor bronze under high strain rates increase by 32.77% and 11.07%, respectively compared with quasi-static condition, the strain hardening index increases from 0.075 to 0.251, and the strain rate sensitivity index for material strength changes from 0.005 to 0.022, which presents a clear sensitivity to strain rates. The deformation resistance increases with the increasing of the strain rate due to the stronger short range resistance induced by the acceleration of dislocation motion. The ability of plastic deformation of C5191 phosphor bronze increases due to the number of movable dislocations increase significantly, multi-line slip start, and the soft effect of adiabatic temperature rise at the strain rate ranging from 500 to 1500 s−1.