斜波压缩下锡的相变和层裂行为
PHASE TRANSITION AND SPALL BEHAVIOR OF TIN UNDER RAMP WAVE COMPRESSION
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摘要: 获取不同热力学路径下锡的动态响应实验数据, 是深入研究其相变和损伤物理过程的基础. 利用小型磁驱装置CQ-4完成了金属锡的斜波加载实验, 获取了锡含有相变和层裂损伤物理信息的实验数据. 实验结果显示, 在加载段锡依次经历了弹塑性转变和β-γ相变两种物理过程, 屈服强度约0.194 GPa, 相变压力随着锡厚度的增加从7.54 GPa减小到7.14 GPa. 在卸载段出现了明显的层裂损伤, 层裂强度约1.1 GPa, 与相同加载压力下冲击实验结果有巨大差异, 层裂片厚度约0.38 mm. 结合由锡的多相Helmholtz自由能计算的多相状态方程、Hayes相变动力学方程和损伤度理论, 对斜波压缩实验过程进行一维流体动力学数值模拟, 计算结果可以很好描述锡的弹塑性转变、相变和层裂三个物理过程.Abstract: Obtaining the dynamic response experimental data of tin under different thermodynamic paths is the basis for in-depth study of its phase transition and damage physical process. The ramp wave compression experiment of tin was carried out by using magnetic driving loading device CQ-4, and the dynamic response data of tin were obtained. The experimental results show that in the loading section, tin undergoes elastic-plastic transformation and β-γ phase transition. The yield strength is about 0.2 GPa, and the phase transition onset pressure decreases from 7.54 GPa to 7.14 GPa with the increase of tin thickness. There is obvious spallation damage in the unloading section. The spallation strength is about 1.1 GPa, which is greatly different from the impact test results under the same loading pressure. The thickness of the spallation is about 0.38 mm. Combined with the multiphase equation of state based on Helmholtz free energy, nonequilibrium phase strain rate model and damage evolution equation, the experimental dynamic process is numerically simulated. The calculation results can well describe the three physical processes of elastic-plastic transformation, phase transition and spallation.