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利用光学显微镜和扫描电镜对Ni3Al基单晶合金IC21的铸态组织和不同热处理制度后的组织进行了观察,研究了固溶温度和时效温度对合金热处理组织的影响。研究结果表明,IC21单晶合金的铸态组织由γ’相、γ相以及枝晶间的白色块状析出相组成,枝晶干上γ’相尺寸比枝晶间的γ’相尺寸大。IC21单晶合金的初熔温度约为1345℃,热处理窗口约为65℃。枝晶间γ’相的溶解温度低于枝晶干γ’相的溶解温度。固溶温度越高,时效处理后γ’相的尺寸越均匀。一级时效处理温度对γ’相的尺寸、形态和数量有明显影响。随着一级时效温度的增加,γ’相的体积分数和尺寸增加,形状由类球状向立方状再向长条状转变。1320℃/10 h/aac+1060℃/2 h/ac+870℃/32 h/ac热处理后可使合金获得γ’相尺寸和分布均匀且立方度高的优良组织。
The as-cast microstructure and the microstructure of the as-received Ni2Si single crystal alloy IC21 were observed by optical microscopy and scanning electron microscopy. The effects of solution temperature and aging temperature on the microstructure of the alloy were investigated. The results show that the as-cast microstructure of IC21 single crystal superalloy consists of γ ’phase, γ phase and white lump phase between dendrites. The size of γ’ phase in dendrite stem is larger than that of dendrite. IC21 single crystal alloy melting temperature of about 1345 ℃, heat treatment window is about 65 ℃. The melting temperature of the γ ’phase between the dendrites is lower than the melting temperature of the dendritic dry γ’ phase. The higher the solution temperature, the more uniform the γ ’phase size after aging treatment. The first-stage aging temperature has a significant effect on the size, shape and amount of γ ’phase. With the increase of first-stage aging temperature, the volume fraction and size of γ ’phase increased, and the shape changed from quasar-sphere to cube-shape to strip-shape. After heat treatment at 1320 ℃ / 10 h / aac + 1060 ℃ / 2 h / ac + 870 ℃ / 32 h / ac, the alloy has excellent γ ’phase size and distribution and high cubicness.