摘要:
针对包含高密度、高热值元素的高熵合金材料在聚能战斗部药型罩上的应用问题,选取Ta-Hf-Nb-Zr体系高熵合金为研究对象,采用INSTRON材料试验机、分离式霍普金森压杆试验平台,探寻该高熵合金应变率在10-3~103s-1区间、温度在室温25~900℃区间以及应力三轴度在0.33~0.89条件下的力学响应规律,基于静动态力学性能试验结果,获取该合金Johnson-Cook(J-C)本构方程参数A、B、n、C、m及损伤失效模型参数D1~D5,并建立爆炸加载下高熵合金爆炸成型弹丸(Explosively Formed Projectile ,EFP)成型仿真模型。开展EFP成型脉冲X光验证试验,结果显示117μs时刻高熵合金EFP成型较为完整,EFP长度为51.1mm、直径为12.27mm,187μs EFP尾部产生三处断裂,头部长度为24.3mm,直径为12.27mm,EFP速度为2496.3m·s-1。仿真与试验同时刻EFP长度、直径以及速度误差均小于8.2%,断裂形态与试验结果基本一致,应用J-C模型可有效预测了爆炸加载条件下高熵合金EFP的成型状态。
Abstract:
For the application of high-entropy alloy systems containing high-density and high-calorific value elements in the liner of shaped charge warheads, the Ta-Hf-Nb-Zr high-entropy alloy system is investigated. The research employs an INSTRON material testing machine and a split Hopkinson pressure bar testing platform to explore the mechanical response of this high-entropy alloy across a wide range of strain rates from 10-3 to 103s-1, temperatures ranging from 25 to 900°C, and stress triaxiality values from 0.33 to 0.89. Yield strength and failure strain data were obtained from static round bar tensile tests and dynamic compression tests conducted under these varying conditions. Using least squares fitting, the parameters of the Johnson-Cook (J-C) constitutive equation A, B, n, C and m as well as the damage failure model parameters D1, D2, D3, D4 and D5, were derived. Subsequently, a simulation model for explosively formed projectile (EFP) made from high-entropy alloys under explosive loading conditions was developed.Pulse X-ray tests of the EFP formation were performed, and numerical simulations of the EFP formation process were conducted using LS-DYNA software. The results show that at 117 μs, the high-entropy alloy EFP remains largely intact, with a length of 51.1 mm and a diameter of 12.27 mm. At 187 μs, three fractures are observed at the tail of the EFP, with the head length measuring 24.3 mm, the diameter at 12.27 mm, and the EFP speed recorded at 2496.3 m·s-1. The numerical simulations demonstrate that the EFP length, diameter, and