摘要
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。
An observation was made on the microstructure of a single crystal Ni3Al-base superalloy IC21 at as-cast condition and various heat treatment conditions using optical microscope（OM） and scanning electron microscopy（SEM）.The microstructure of the alloy after heat treatment under different solid-solution temperatures and various aging temperatures was investigated.The microstructure observations and analysis indicated that the as-cast alloy consisted of γ′,γ and the white phase which was block like in the interdendritic regions.The size of γ′ phase in the dendrite region was larger than that in the interdendritic region.The incipient melting temperature of IC21 alloy was about 1345 ℃ and the heat treatment window was 65 ℃.The solid-solution temperature of the γ′ phase in the interdendritic regions was lower than that in the dendrite regions.The higher the solid-solution treatment temperature,the homogeneous the size of γ′ precipitate.The size,morphology and the volume fraction of γ′ precipitate after complete heat treatment were all connected to the primary aging temperature.With the increase of primary aging temperature,the size and the volume fraction of γ′ precipitate increase,the morphology of the γ′ precipitate gradually changed from near-spherical to cuboidal and then to elongate shape.Appropriate microstructural feature was achieved through the 1320 ℃/10 h/aac＋1060 ℃/2 h/ac＋870 ℃/32 h/ac treatment.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2012年第2期178-183,共6页
Chinese Journal of Rare Metals
基金
国家自然科学基金(50971005)资助项目
关键词
γ'相
热处理
显微组织
Ni3Al基单晶合金
γ′ phase
heat treatment
microstructure
Ni3Al-base single crystal superalloy
