Laser Multi-layer Cladding Experiment on the DD3 Single Crystal Using FGH95 Powder:Investigation on the Microstructure of Single Crystal Cladding Layer  

在DD3单晶上进行FGH95粉末激光多层涂覆:单晶涂层组织形式规律研究

作　　者：FENG Li-ping HUANG Wei-dong LIN Xin YANG Hai-ou LI Yan-min Yang Jian 冯莉萍;黄卫东;林鑫;杨海鸥;李延民;杨健

机构地区：[1]State Key Iaboratory of Soldification Processing,Northwestern Palytechnical University,Xi'an 710072,China

出　　处：《Chinese Journal of Aeronautics》2002年第2期121-127,共7页中国航空学报(英文版)

基　　金：National Key Basic Research Development Program me of china(No.G2000067205-3)

摘　　要：Laser multi\|layer cladding experiments were performed on the substrate of DD3 single crystal with FGH95 powder as cladding material.The solidification microstructure in the sample was investigated.It was found that the solidification microstructure was greatly influenced by the crystallography orientation of the substrate and the local solidification conditions.When the angle between the preferred orientation of the single crystal and the direction of heat flow in the cladding layer is less than 30°,single crystal cladding layers were acquired.Otherwise the crystallography orientation of the cladding layer will deviate from the orientation of the substrate and the microstructure with polycrystalline appears.Meanwhile,even when the experiments were performed on the same preferred crystal surface,the solidification microstructures will be different distinctly resulting from the variation of the local solidification conditions.The secondary arms were degenerated and the primary arm spacing was about 10\|20μm.Further investigation shows that the phases of the cladding layer are mainly made up ofγ,γ′,the flower\|likeγ/γ′eutectic and carbide.The morphology ofγ′was cubical and the size is less than 0.1μm.利用高温合金FGH95粉末在DD3单晶的不同品面上进行激光多层涂覆实验.深人研究了涂覆层中凝固显微组织的生长规律。研究表明基材的品体取向和局部凝固条件对涂层中的凝固显微组织有很大的影响。当单品基材择优品向与热流方向夹角小于30°时,可以得到从基材上外延生长的单品,涂层内二次臂退化,枝品一次间距为10~20μm;当实验所在的单晶基材的择优晶向与热流的方向夹角大于30°时。涂层中晶体取向偏离基材的取向,并出现多品。即便当实验在同一个择优晶面上进行时,局部凝固条件不同,涂层内的凝固显微组织也有很大的差别。二次臂退化,一次臂间距大约为10~20μm,进一步的研究表明,涂层中主要组成相为枝晶干上分布的基体相y和沉淀硬化相丫以及枝品间的y+丫花状共晶和少量碳化物.X相主要为具有良好强化效果的细小立方体.尺度约为0.1μm。

关 键 词：laser metal forming directional solidification laser multi-layer cladding single crystal MICROSTRUCTURE composition segregation 

分 类 号：V252[一般工业技术—材料科学与工程] TG132[航空宇航科学与技术—航空宇航制造工程]