纯铁药型罩材料的动态应力-应变行为

Dynamic stress-strain behavior of pure iron for shaped charge liners

利用Hopkinson杆技术对经930℃下退火2h的纯铁药型罩材料进行了冲击压缩实验,测定了该材料在不同应变率下的动态应力-应变关系.借助光学显微镜对变形后纯铁的组织进行了观察,研究了在不同应变率下变形过程中纯铁的组织演变和动态应力-应变行为.研究表明:在650～3850s-1的应变率范围内,纯铁药型罩材料有显著的孪生变形,发生了明显的应变强化和应变率强化效应,且最大应变也随应变率的提高而增加;在高应变率冲击下,孪生和滑移是纯铁的主要塑性变形机制,也是纯铁高应变率增强增塑的主要机制.

The shock compression experiments of pure iron for shaped charge liners after annealing at 930℃ for 2 h were carried out with the split Hopkinson pressure bar apparatus, and its dynamic stress-strain relationships were measured at different strain rates. The microstructure of the deformed pure iron was examined by optical microscope. The microstructure evolution occurring at different strain rates and dynamic stress-strain behavior were investigated. It is shown that pure iron for shaped charge liners has the twinning structure after impact compression. The effect of work-hardening and strain rate strengthening for pure iron occurs at the strain rates of 650 to 3 850 s^-1, and the maximum strain also rises with increasing strain rate. Twinning and slipping are the plastic deformation mechanism of pure iron under the shock of high strain rate, which leads to the increase in both strength and plasticity at high strain rate for pure iron.