电子束层覆凝固层厚对GH4068铸态组织和合金元素偏析行为的影响  

Study on the As-Cast Microstructure and Segregation Behavior of Alloying Elements in GH4068 by an Electron Smelting Layer Thickness Overlay

作　　者：陈瑶瑶 谭毅[1,2] 白如圣 宁莉丹 崔传勇[3] 李鹏廷[1,2] CHEN Yaoyao;TAN Yi;BAI Rusheng;NING Lidan;CUI Chuanyong;LI Pengting(School of Materials Science and Engineering,Dalian University of Technology,Dalian 116024,China;Key Laboratory for Energy Beam Metallurgy and Advanced Materials Preparation of Liaoning Province,Dalian University of Technology,Dalian 116024,China;Superalloys Division,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]大连理工大学材料科学与工程学院,辽宁大连116024 [2]大连理工大学辽宁省载能束冶金及先进材料制备重点实验室,辽宁大连116024 [3]中国科学院金属研究所高温合金部门,辽宁沈阳110016

出　　处：《铸造技术》2024年第9期855-864,共10页Foundry Technology

基　　金：国家重点研发计划(2019YFA0705300)。

摘　　要：利用电子束层覆凝固的工艺方法制备GH4068,并研究不同层覆凝固厚度对样品组织和元素偏析的影响。结果表明,层覆凝固厚度为5.2 mm(533 g)的样品元素挥发程度最严重,整体组织由底部粗大无序晶粒和其余部分连续柱状晶组成。层覆凝固厚度为7.8 mm的样品层间出现细晶层,其显微硬度最高可以达到452.2 HV。层覆凝固厚度为15.5 mm的样品因层覆厚度太大导致电子束熔透能力不足从而出现层间间隙。在控制元素挥发程度前提下,层覆凝固厚度为7.8 mm的铸锭偏析程度最小且二次枝晶间距最小。偏析最严重的元素为Ti和W,相比于传统双联熔炼工艺,电子束层覆熔炼制备的样品W和Ti偏析程度分别降低11.2%和6.65%。综上,最佳层覆厚度为7.8 mm。GH4068 was prepared by electron beam layer smelting(EBLS),and the effects of different layer thicknesses on the microstructure and element segregation of the samples were studied.The results show that the sample with a solidification thickness of 5.2 mm(533 g)has the most severe element volatilization.The overall structure was composed of coarse disordered grains at the bottom and continuous columnar grains at the bottom.A fine-grained layer appears between the sample layers with a solidification thickness of 7.8 mm,and the microhardness of the fine-grained layer can reach 452.2 HV.For the sample with a solidification thickness of 15.5 mm,the electron beam penetration capacity is insufficient due to the large thickness of the layer,which results in interlayer gaps.Under the premise of controlling the volatilization degree of the elements,the ingot segregation degree with a solidification thickness of 7.8 mm is the smallest,and the secondary dendrite spacing is the smallest.The most serious segregation elements are Ti and W.Compared with those of the traditional duplex smelting process,the W and Ti segregation degrees of the samples prepared by electron beam layer smelting are reduced by 11.2%and 6.65%,respectively.In summary,the optimal layer thickness is 7.8 mm.

关 键 词：GH4068 电子束熔炼 层覆凝固 组织形貌 元素偏析 

分 类 号：TG113.12[金属学及工艺—物理冶金]