镍基高温合金高温塑性变形的流动应力变化及微观组织特征

Flow Stress Variation and Microstructure Characteristics of Ni-based Superalloys during High-temperature Plastic Deformation

在变形温度1000~1100℃、变形速率0.001~1 s^(-1)、应变0.9条件下对镍基高温合金进行单轴压缩试验。采用EBSD研究了试样的显微结构,分析了合金在热变形过程中的真应力-真应变曲线中动态软化和应变硬化两个阶段的微观组织演变规律,包括晶粒尺寸、局部取向差及其相对迁移率的交互作用。对动态软化机制和应变硬化现象进行了解释,找到了合金的动态再结晶形核及核心长大的决定性特征参数及其演变规律。

Uniaxial compression experiments of Ni-based superalloys were carried out at deformation temperature of1000-1100℃,strain rate of 0.001-1 s^(-1)and strain of 0.9.The microstructure of the samples was studied by using EBSD.The microstructure evolution of the alloy in the two stages of dynamic softening and strain hardening in the true stress-true strain curves during hot deformation was analyzed,including the interaction of grain size,local misorientation,and its relative mobility.The dynamic softening mechanism and strain hardening phenomenon were explained.The decisive characteristic parameters and their evolution laws of dynamic recrystrallization nucleation and core growth of the alloy were found.