亚固溶热处理对镍基粉末高温合金双重晶粒组织的影响

Influence of sub-solvus heat treatment on dual grain microstructure in a nickel-based powder metallurgy superalloy

采用热力学相计算、光学显微镜和场发射扫描电镜等实验方法研究了镍基粉末高温合金进行亚固溶热处理对合金双重晶粒组织的影响。结果表明:合金热处理过程中固溶温度和时间是控制合金晶粒尺寸的重要因素。合金中γ'相的固溶温度为1160℃。锻态合金在固溶热处理前先进行亚固溶热处理,可使锻态组织的晶粒尺寸均匀化,有利于固溶热处理控制晶粒尺寸,得到合适的晶粒度;在合金固溶热处理后再进行亚固溶热处理,晶粒尺寸发生适度的粗化和长大,有利于调整固溶热处理后的晶粒尺寸以改善合金力学性能。

The influence of the sub-solvus heat treatment on dual grain microstructure in a nickel-based powder metallurgy superalloy was studied by means of thermodynamic calculation, optical microscope and field scanning electron microscopy. The results show that during the heat treatment process the key factors in controlling the grain size of the alloy are solution temperature and time. The γ＇ solvus temperature of this alloy is 1160 ℃. Applying a sub-solvus heat treatment before the as-forged alloy is solution heat treated, grain size of the alloy would be homogenized, which results in obtaining appropriate grain size. Applying a sub-solvus heat treatment after the alloy is solution heat treated would cause growth and coarsening of the grains, and this would help to optimize grain size of the alloy, which is good for the improvement of the alloy＇ s mechanical properties.