Shock Compression Behaviors and the Correlation with Microstructures of Ceramic Materials

陶瓷材料硬而脆，具有较大的晶体各向异性。陶瓷在激波压缩下的屈服和相变很大程度上取决于它们的特性。通过高质量试样的冲击波测量和恢复实验，研究了各种陶瓷材料的冲击屈服性能、高压相变、状态方程等及其与材料特性的关系。冲击压缩实验采用熊本大学的粉末炮、日本东北大学的两级光气炮和高速镜转式条纹相机进行。研究了立方氧化锆和四边形氧化锆高压相的弹塑性转变、相变和EOS，明确了晶体结构和晶体状态的影响。在四角形氧化锆上发现了异常的Hugoniots和大的片状物，并讨论了它们与ph值的关系。研究了Si_3N_4单片陶瓷和SiC晶须掺杂陶瓷的微观结构对陶瓷强度的影响。测量了AIN的Hugoniot压缩曲线，研究了AIN的弹塑性转变、相变、状态方程以及晶粒的影响。b_4c多晶和Al_2O_3单晶在弹塑性区和塑性区均出现了自由表面的锯齿状分布，表明裂纹在弹塑性转变过程中起着重要作用。测定了LiF单晶的各向异性能谱。测量了ZnS和ZuSe的Hugoniot压缩曲线，证实了ZuS和ZnSe的相变，ZnS上发现了一个新的相变。自行研制了激光速度干涉仪（VISAR），成功测量了钢的粒子速度历史。此外，还制作了长脉冲YAG双频激光器用于光学测量。少

Ceramic materials are hard but brittle, and have large crystal anisotropy. The yielding and phase transition unser shock compression of ceramics strongly depend on their characterizations. In this study, the shock yielding property, high-pressure phase transition, equation of state, etc.of various kinds of ceramic materials ant the correlation with material characterizations were investigated by the shock-wave measurements and recovery experiments using high-quality specimens. The shock compression experiments were performed by using a powder gun of Kumamoto University, a two-stage light gas gun of Tohoku University and the high-velocity mirror-rotating type streak cameras.The elastoplastic transition, phase transition and EOS of the high-pressure phase of the cubic and tetragonal zirconia were studied, and the effects of crystal structure and crystal state were clarify. The anomalous Hugoniots and large spall property were found on the tetragonal zirconia, and the correlations with ph … More ase transition were discussed. The effects of microstructure on the strength were investigated on monolithic Si_3N_4 ceramics and the SiC whisker-doped ceramics. The Hugoniot compression curve of AIN was measured, and the elastoplastic transition and phase transition, equation of state and also the effect of crystal grain were studied. The jagged profiles of free-surface in elastic and plastic region were observed on B_4Cpolycrystal and Al_2O_3 single crystal, which indicated that cracks playd an important role in the elstoplastic transition. The anisotropic HEL of LiF single crystal was measured.The Hugoniot compression curves of ZnS and ZuSe were measured, and the phase transitions were confirmed on ZuS and ZnSe and a new phase transition was found on ZnS.The VISAR system (Laser-Velocity Interferometer) was produced ourselves, and the particle-velocity history of a steel was succeeded in measurement. In addition, a long pulsed YAG double frequency lase was also produced for the optical measurements. Less