GH864合金组织特征对裂纹扩展速率的影响  

Effect of microstructure characteristics on the fatigue crack propagation rate of GH864 alloy

作　　者：姚志浩[1] 董建新[1] 张麦仓[1] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083

出　　处：《北京科技大学学报》2011年第12期1501-1507,共7页Journal of University of Science and Technology Beijing

基　　金：国家自然科学基金资助项目(51071017)

摘　　要：利用光学显微镜、场发射扫描电镜等手段,研究了GH864合金三种轧制态组织经热处理后的演变过程,分析了热处理后不同组织对室温冲击韧性及高温650℃裂纹扩展速率的影响.结果表明,GH864合金由初始轧制态组织经标准热处理后(1020℃,4h/空冷→845℃,4h/空冷→760℃,16h/空冷)获得的晶粒组织,其晶粒组织演变具有明显的一致性,而合金的晶界碳化物分布及基体γ'强化相没有明显差别,其分布状态及尺寸大小基本一致.热处理后的晶粒尺寸越大,抗裂纹扩展能力越好,合金的室温冲击韧性越低;热处理后形成的项链状组织,对合金冲击韧性及裂纹扩展速率有较好的影响.The evolution of three different initial microstructures of GH864 alloy after heat treatment was studied by optical microscopy（OM） and field emission scanning electron microscopy（FESEM）.The impact toughness at room temperature and crack propagation rate at 650℃ were analyzed after heat treatment.The results indicate that the grain microstructural evolution of GH864 alloy is hereditary between initial forging state and heat treatment state after 1020℃,4h/air cooling→845℃,4h/air cooling→760℃,16h/air cooling,while carbides in grain boundaries and γ′ phases are not significantly different.The larger the grain size,the better crack propagation behavior the alloy has,and the worse the impact toughness is.It is highlighting that the necklace microstructure has a better effect to improve the impact toughness and crack propagation behavior of GH864 alloy.

关 键 词：高温合金 镍基合金 组织转变 析出相 裂纹扩展 

分 类 号：TG132.32[一般工业技术—材料科学与工程]