本文利用扫描电子显微镜（ SEM），研究了Ni⁃Al二元模型镍基单晶高温合金在热暴露实验过程中γ′相尺寸与体积分数的变化。结果表明：随着热暴露时间的增加，一次γ′相尺寸明显增大，其长大机制为扩散控制的粗化机制（L⁃S⁃W理论）。其平均尺寸的立方与热暴露时间呈线性关系。通过对γ′相体积分数的统计显示，γ′相体积随热暴露时间的延长而减小，这是高温下γ相固溶度增加以及γ′溶解的结果，可以用Ni⁃Al二元相图来解释此现象。%The change of γ′phase size and volume fraction in a Ni⁃Al binary model nickel⁃based single⁃crystal alloy during the thermal exposure treatment were investigated by the scanning electron microscopy. The results show that the primaryγ′precipitates grow up in size with the increase of thermal exposure time. The growth of γ′ precipitate is controlled by diffusion mechanism ( L⁃S⁃W mechanism) . The size ofγ′particles is proportional to the thermal exposure time t1/3 . The volume fraction ofγ′phase decreases with the increase of the thermal exposure time, which is due to γ′phase dissolution at high temperature. It can be explained by the Ni⁃Al phase diagram.
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