一种新型第三代镍基粉末高温合金亚固溶热处理对调控γ"相分布的研究

Sub-solvus heat treatment study on the γ" distribution of a novel nickel-based superalloy

摘要:

本工作研究了热处理工艺对一种新型第三代镍基粉末高温合金FGH4113A(WZ-A3)的γ"相组织的影响规律。主要探究了亚固溶热处理的温度、保温时间、冷却速度，以及过固溶+亚固溶、亚固溶+亚固溶对γ"相的影响。结果表明：亚固溶温度越接近γ"相固溶温度，回溶越多；γ"相的回溶倾向与尺寸成反比；晶内未回溶的γ"相尺寸与保温时间呈正比，数量与保温时间呈反比；晶界γ"相尺寸随保温时间增加而增大；γ"相总体积分数随保温时间增加没有明显变化；使用较快的冷速可使晶内重新析出细小的单模组织；使用较慢的冷速可使晶内重新析出多模组织；回溶析出的γ"相尺寸与冷却速度成反比；过固溶+亚固溶热处理后的组织主要受亚固溶热处理的温度和冷速影响，温度越低，晶内的矩形γ"相越多；小尺寸球形γ"相在高温阶段会粗化成矩形，受γ/γ"相的错配度绝对值影响；亚固溶+亚固溶热处理的组织受温度影响较大，根据温度的不同，γ"相组织会有各种变化。

Abstract:

The paper investigated the influence of sub-solvus heat treatment processes on the γ" phase microstructure of a novel third-generation nickel-based powder superalloy FGH4113A(WZ-A3). The temperature, soaking time, cooling rate of sub-solvus heat treatment, and the effects of super-solvus + sub-solvus, sub-solvus + sub-solvus on γ" phase were mainly explored. The results indicate that: the volume fraction of γ" phase is inversely proportional to the sub-solvus heat treatment temperature; the tendency of γ" phase dissolve back intoγ phase is inversely proportional to the size, and the quantity is inversely proportional to the soaking time; the size of grain boundary γ" phase increases with the increase of soaking time; the overall volume fraction of γ" phase does not change significantly with the increase of soaking time; a fast cooling rate can re-precipitate an intergranular fine unimodal γ" phase structure; a slower cooling rate can re-precipitate intergranular multimodal γ" phase structure; the size of the reprecipitated γ" phase is inversely proportional to the cooling rate; the microstructure after super-solvus + sub-solvus heat treatment is mainly affected by the temperature and cooling rate of the sub-solvus heat treatment, the lower the temperature, the more rectangular γ" phases are in the grain; the small size spherical γ" phase will be coarsened into a rectangle shape at high temperature, which is affected by the absolute value of the mismatch degree of the γ/γ" phase; the γ" phase microstructure of sub-solvus + sub-solvus heat treatment is greatly affected by temperature.