新型铸&锻GH4198合金组织特征及偏析行为  

Microstructural Characteristics and Segregation Behavior of a Newly Developed Cast & Wrought Superalloy GH4198

作　　者：李福林 谭海兵[3] 孟令超 付锐 钟燕 杜金辉[1,2] Li Fulin;Tan Haibing;Meng Lingchao;Fu Rui;Zhong Yan;Du Jinhui(GaoNa Aero Material Co.,Ltd,Beijing 100081,China;Department of High-Temperature Materials,Central Iron and Steel Research Institute,Beijing 100081,China;Sichuan Gas Turbine Research Institute of AECC,Chengdu 610400,China)

机构地区：[1]北京钢研高纳科技股份有限公司,北京100081 [2]钢铁研究总院高温材料研究所,北京100081 [3]中国航发四川燃气涡轮研究院,四川成都610400

出　　处：《稀有金属》2020年第8期807-815,共9页Chinese Journal of Rare Metals

基　　金：中国博士后科学基金项目(2017M613235)资助。

摘　　要：采用真空感应+电渣重熔连续定向凝固双联工艺制备新型铸&锻GH4198合金定向凝固铸锭。利用场发射扫描电镜(FESEM)、能谱(EDS)、电子探针(EPMA)研究和分析了合金的铸态组织特点、凝固偏析行为、均匀化热处理制度,并对合金凝固过程进行了讨论。结果表明:采用电渣重熔连续定向凝固技术制备的铸锭可消除常见的中心等轴晶区而呈现发达的柱状晶组织,R/2处柱状晶的轴向偏离角度小于20°。GH4198合金在凝固过程中,Al,Mo,Ti,Nb和Ta等元素主要在枝晶间偏析;W,Cr和Co等元素主要偏析在枝晶干;铸锭边部元素偏析系数更低,心部和二分之一半径处(R/2)的元素偏析系数相当。铸态合金中主要析出相为γ′相,一次碳化物,共晶相及其凝固前沿的η相、硼化物相和富锆相。经过均匀化热处理后共晶相、η相、硼化物和锆化物相可彻底回溶至基体,采用最高台阶温度为1195℃保温12 h的均匀化热处理制度后各元素扩散充分。A newly developed cast&wrought GH4198 alloy ingot was prepared by vacuum induced melt and electric slag remelting continuously directionally solidification(ESR-CDS).The as-cast microstructural characteristics,solidification behavior,and homogenizing treatment were analyzed by field emission scanning electron microscopy(FESEM),energy dispersive spectrum(EDS)and electron probe microanalysis(EPMA),and the solidification process was discussed.The results showed that the central equiaxed crystals could be eliminated in the ingot prepared by ESR-CDS,and the ingot exhibited developed columnar crystal structure.The deviation angle of columnar grain from axial direction was less than 20°.Al,Mo,Ti,Nb and Ta elements mainly segregated at interdendritic region.W,Cr and Co mainly segregated at dendrites.The element segregation coefficient of side of the ingot was much lower than the center and R/2 sites which showed equivalent segregation levels.The precipitation phases in the ingot includedγ′,primary carbides,γ′-γeutectic,borides,ηphase and Zr-rich phase.The experimental study of homogenization heat treatment was carried out.γ′-γeutectic,borides,carbides andηphase could dissolve into matrix.Refractory elements diffused evenly at 1195°C for 12 h.

关 键 词：铸&锻GH4198合金 电渣重熔连续定向凝固 凝固偏析 均匀化处理 

分 类 号：TG132.3[一般工业技术—材料科学与工程]