【摘要】 采用弹/塑性应力-应变有限元方法计算了[011]取向单晶镍基合金中γ /γ’ 两相共格界面的von Mises应力及应变能密度分布特征,研究了施加压应力对γ /γ’ 两相界面von Mises应力分布及γ’相定向粗化规律的影响。结果表明:[011]取向单晶镍基合金经热处理后,组织结构是立方γ’相以共格方式嵌镶在γ基体相中,并沿<100>γ方向规则排列。当沿[011]方向施加压应力时,(100)晶面沿[001]γ和[010]γ方向发生晶格收缩,其晶格收缩的挤压作用可排斥半径较大的Al、Ti原子,而在(010)和(001)晶面则分别沿[100]取向发生晶格扩张应变,可诱捕半径较大的Al、Ti原子,是促使γ’相在(100)晶面交错生长成网状结构,并沿[010]和[001]取向扩散连接,生长成为相互垂直的层片网状筏形组织的主要原因。更多还原

【Abstract】 The distribution of the von Mises stress and strain energy density in the regions near the interfaces of γ /γ’ phases were calculated by the elastic-plastic stress-strain finite element method (FEM), and the influences of the applied stress on the von Mises stress distribution and the coarsening regularity of γ’ phase in a [011] oriented single crystal nickel-based superalloy were investigated. Results show that after heat treating for the [011] oriented single crystal nickel-base superalloy, the cubical γ’ phase is embedded coherently in the γ matrix, and arranges regularly along the <100> direction. When the compressive stress is applied along the [011] direction, the lattice contraction of (100)γ’plane along [001] and [010] directions occurs, whose extrusion action may reject the Al and Ti atoms with bigger radius, while the expansion strain on (010)γ’and (001) γ’ planes takes place along the [100] orientation which may trap the Al and Ti atoms with bigger radius to promote the directional growing of γ’ phase in the (100) plane along the [010] and [001] orientations, which is thought to be the main reason of the γ’ phase grown directionally into the mesh-like rafted structure.更多还原