【摘要】 研究镍基单晶高温合金在固溶处理和时效处理过程中显微结构的变化,对于更精细地制定热处理制度有重要的参考价值。本文利用电子探针(EPMA)、透射电镜(TEM)和扫描电镜(SEM),研究了Ni-Al-W三元镍基模型高温合金中元素枝晶偏析、相分配及显微结构的变化。研究结果表明:铸态时,W偏析在枝晶干,γ′相粗大且不规则;固溶处理后,γ′相细小且分布均匀;完全热处理后,γ′相尺寸增加,立方度变好,W择优分配在γ′相中。更多还原

【Abstract】 The research on the microstructure changes of nickel-based single crystal superalloy during solution and aging treatment has important reference value for a more precise formulation of heat treatment schedule. The electron probe micro-analyzer(EPMA), transmission electron microscope(TEM) and scanning electron microscope(SEM) are used to investigate the dendrite segregation, the phase distribution, and the evolution of microstructure during heat treatment in Ni-Al-W ternary nickel-based model single crystal superalloy. In the casting alloy, W segregates in the dendrites, and γ′ precipitates are coarse and irregular. After solution treatment, γ′ precipitates are fine, and their distributions are uniform. After full heat treatment, the size of γ′ phase increases, the shape of γ′ precipitates become more cubic, and W prefers to distribute to γ′ phase.更多还原