CaTiO3－钙钛矿的晶体结构相变、高温流变及其下地幔地球动力学意义

利用高精度的ＭＴＳ材料实验系统，在１４７３－１６７３Ｋ的温度区间和可控热力学环境条件下，对［１００］ｐｃ和［１１０］ｐｃ两个方位的ＣａＴｉＯ₃－钙钛矿单晶体进行了高温蠕变试验，着重观测了晶体结构相变和高温流变的相关性．研究表明，钙钛矿的晶体结构相变对其高温流变性质有明显影响，斜方晶系钙钛矿蠕变强度大大高于四方和立方晶系钙钛矿，后两者具有很强的高温塑性各向异性．在分析相变过程晶体结构变化特征和观测到的高温流变数据基础上，认为钙钛矿晶体结构相变中发生的位错结构的变化是导致其高温流变性变化的主要物理机制．

CRYSTAL STRUCTURAL PHASE TRANSITIO N AND HIGHTEMPERATURE CREEP OF CaTi3-PEROVSKITE:IMPLICATIONSFOR THE LOWER MANTLE GEODYNAMICS

To study the correlation between crystal structural phase transition and high temperature plasticity,ingle crystal CaTiO₃-perovskite has been deformed along[100]pc and[110]pc orientations at T=1473-1673K and oxygen fugacities,o2=10-20-10-3MPa in a high precision MTS system.xperimental results showed a clear in fluence of phase transition on creep behavior of CaTiO₃-perovskte:reep strength of it's orthorhombic phase is significant higher than that of it's tetragonal phase and cubic phase,he high-T creep of the tetragonal and the cubic phases of CaTiO₃ perovskte are strongly anisotropic.n the basis of creep data and analysis on the crystal structure of different phases,e attribute the effect of phase transition on high-T creep to the change of dislocation core structure associated with phase tran sitions.