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为了探讨C5191磷青铜在高应变速率条件下的动态响应,解决高速冲压工艺问题,利用电子万能材料试验机和分离式Hopkinson拉杆装置对C5191磷青铜分别进行应变速率为0.001和500、1000、1500 s~(-1)的准静态和动态拉伸试验,结合SEM和TEM等手段,研究了C5191磷青铜的动态拉伸性能及其变形机制。结果表明:C5191磷青铜高应变速率动态拉伸与准静态条件相比较,其屈服强度和抗拉强度分别提升了32.77%和11.07%;应变硬化指数由0.075增加到0.251;材料强度的应变速率敏感指数由0.005变化到0.022,呈现出明显的应变速率敏感性;高应变速率动态拉伸过程中,位错运动速度加快,导致位错“近程阻力”加大,使C5191磷青铜的变形抗力随着应变速率的增加而增大。可动位错数量的显著增多,多系滑移的开启,以及绝热温升软化效应在一定程度上提高了C5191磷青铜高应变速率动态拉伸时的塑性。
In order to investigate the dynamic response of C5191 phosphor bronze under high strain rate conditions and to solve the problem of high-speed stamping process, C5191 phosphor bronze was respectively subjected to strain rates of 0.001 and 500, 1000 and 1500 s using an electronic universal testing machine and a split Hopkinson tie- ~ (-1) of quasi-static and dynamic tensile test, combined with SEM and TEM and other means to study the dynamic tensile properties of C5191 phosphor bronze and its deformation mechanism. The results show that the yield strain and tensile strength of C5191 phosphor bronze are increased by 32.77% and 11.07%, respectively, compared with the quasi-static condition. The strain hardening index increases from 0.075 to 0.251. The strain rate of material strength is sensitive Index changes from 0.005 to 0.022, showing a significant sensitivity to strain rate; high strain rate dynamic tensile process, the dislocation speed increases, leading to dislocation “short-range resistance ” increased, the C5191 phosphor bronze deformation Resistance increases with strain rate. The significant increase in the number of mobile dislocations, the opening of multi-line slip, and the softening effect of adiabatic temperature rise to some extent improve the plasticity of C5191 phosphor bronze under dynamic tension with high strain rate.