单晶高温合金中条纹晶缺陷形成原因研究  

Study on the Formation of Sliver Crystal Defect in Single Crystal Superalloy

作　　者：赵运兴 马德新 魏剑辉 徐维台 李重行 徐福泽 皮立波 王富[2] ZHAO Yunxing;MA Dexin;WEI Jianhui;XU Weitai;LI Zhongxing;XU Fuze;PI Libo;WANG Fu(Wedge Central South Research Institute,Shenzhen 518045,China;School of Mechanic and Electronic Engineering,Xi'an Jiao Tong University,Xiran 710049,China)

机构地区：[1]深圳万泽中南研究院,广东深圳518045 [2]西安交通大学机电工程学院,陕西西安710049

出　　处：《铸造技术》2021年第3期163-167,共5页Foundry Technology

基　　金：国家自然科学基金项目(91860103);发动机高温合金材料与部件研发技术国家地方联合工程研究中心(深圳MSZDRC 20181000)。

摘　　要：采用1种第3代单晶高温合金W Z30的返回料合金锭浇注了单晶试棒,发现铸件表面产生严重的条纹晶缺陷。检查结果显示,条纹晶均起源于为丝状或絮状的氧化物夹杂。经过能谱分析,发现该氧化物主要由氧元素和铝元素组成,为氧化铝夹杂。对浇注所用的母合金锭进行了取样分析,结果发现了相同成分和形貌的夹杂物,表明本实验铸件表面的条纹晶是由母合金中氧化铝夹杂引起。这些氧化夹杂在熔化时成为液态浮渣,浇注时以絮状形态随金属液进人模壳型腔,依附在模壳内壁上。在定向凝固过程中,这些夹杂嵌入生长的枝晶干,使其强度大幅降低,在各种应力作用下发生断裂和偏转而成为条纹晶晶粒。A third generation single crystal superalloy(WZ30)was used to pour single crystal test bar in the returned alloy ingot.There were serious stripe defects on the surface of the castings,which originated from filamentous or flocculent oxide inclusions.The sliver defects on the surface of the parent alloy ingot and the castings were analyzed by EDS spectrum anakysis.The results show that the streaks on the surface of the casting are caused by alumina inclusions in the parent alloy.Oxidation inclusions become liquid scum during melting,and enter the mold cavity with metal liquid in flocculent form during pouring,and attach to the inner wall of the mold shell.In the process of directional solidification,these inclusions embedde in the dendritic stem,which greatly reduce the strength of the dendritic stem.Under the action of various stresses,these inclusions fracture and deflect into sliver grains.

关 键 词：单晶高温合金 条纹晶 微观组织 氧化夹杂 

分 类 号：TG146[一般工业技术—材料科学与工程] TG113[金属学及工艺—金属材料]