K447A合金的热处理组织和拉伸性能研究  

Study on the Heat-Treated Microstructure and Tensile Property of K447A Alloy

作　　者：谷怀鹏[1] 李相辉[1] 盖其东[1] 汤鑫[1] 

机构地区：[1]北京航空材料研究院先进高温结构材料重点试验室,北京100095

出　　处：《铸造》2014年第8期824-827,共4页Foundry

摘　　要：通过对K447A合金在不同热处理状态下的显微组织观察和拉伸性能测试,研究了合金显微组织的演变规律及其对拉伸性能的影响。结果表明,合金铸态组织主要包括γ基体、γ′相、碳化物及γ/γ′共晶,碳化物多分布于晶内枝晶干和晶界。固溶处理后,γ′相由大、小两种尺寸的组成,碳化物发生"碎化",且由γ′相包覆,同时枝晶间处析出了细小的MC型碳化物。高温(1100℃)时效热处理使γ′相长大,同时再次析出细小γ′相;低温(870℃)时效热处理则使γ′相形貌接近长方形。拉伸性能结果表明,合金经固溶热处理和时效热处理后的抗拉强度相近,但时效热处理后的伸长率有所增加。The heat-treated microstructure and tensile property of K447A alloy have been investigated in the study. The results reveals that as cast microstructure were composed of γ matrix, γ′phase, MC carbide and γ/γ′eutectic. Carbide precipitated in the dendritic core and along grain boundary. After solid solution heat treatment, γ′ precipitates with two obviously distinct size existed in the dendrite core and interdendritic region, respectively. The carbide phases were surrounded by γ′ phases in the grain interior. Meanwhile, fine MC-type carbide precipitated in the interdendritic region. The size of γ′ become large after solid-solution heat treatment and finer γ′ precipitated again. The morphology of γ′ was cuboidal. The investigation of mechanical properties suggested that the tensile strength was nearly in as-casted and heat-treated condition, while the elongation increased after aging heat treatment.

关 键 词：K447A合金 热处理 显微组织 拉伸性能 

分 类 号：TG132.3[一般工业技术—材料科学与工程]