Microstructural evolution and micro-mechanical properties of non-isothermal solidified zone in TLP bonded Ni-based superalloy joints  

作　　者：Yi Zhang Yiming Zhong Yongxin Cheng Neng He Lianlong He Zhenhuan Gao Xiufang Gong Chunlin Chen Hengqiang Ye 

机构地区：[1]Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China [2]School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China [3]Beijing National Laboratory for Molecular Sciences,Institute of Chemistry,Chinese Academy of Sciences,Beijing 100190,China [4]State Key Laboratory for Long-life High-Temperature Materials,Deyang 618000,China [5]Ji Hua Laboratory,Foshan 528200,China

出　　处：《Journal of Materials Science & Technology》2024年第18期9-22,共14页材料科学技术（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.52125101);the Basic and Applied Basic Research Major Program of Guangdong Province,China(Grant No.2021B0301030003);the Jihua Laboratory(Project No.X210141TL210).

摘　　要：Transient liquid phase(TLP)bonding is a promising process for the joining and repairing of nickel-base superalloys.One of the most important parameters in TLP bonding is the bonding time required for suf-ficient isothermal solidification which prevents the formation of undesirable precipitated phases.In the present work,the effect of bonding time on the microstructure,type,and evolution of precipitates in the non-isothermal solidified zone(NSZ)and their effect on micro-mechanical properties were systemat-ically investigated using multi-scale tests in TLP bonded Mar-M247 superalloy joints with Ni-15.2Cr-3.74B interlayer at 1230℃.For a bonding time of 5 min,dual-phase M_(23)(C,B)_(6)-γ/γ’(where M is a mix-ture of Hf,Ta,Cr,and Ni)with eutectic configuration was formed in NSZ.With the increase in bonding time,the evolution of NSZ microstructure can be summed up as eutectic M_(23)(C,B)_(6)-γ/γ’,semi-striping dual-phase M_(23)(C,B)_(6)-γ/γ’,discontinuously striping M_(23)(C,B)_(6)-γ/γ’,followed by the disintegration of NSZ.As the NSZ counterpart,the isothermal solidified zone(ISZ)is mainly composed ofγ/γ’.Ac-companied by the dissolution of M_(23)(C,B)_(6) in the centerline,the proportion of the ISZ increases greatly until the joints are completely occupied by ISZ.Finally,a bamboo-like structure with domain size of-100μm was formed in the joint centerline,along withγ’reorganized themselves all into cubic shapes and distributed homogeneously.Mechanical property tests demonstrated that in comparison to samples with longer bonding time,the NSZ of the shortest bonding time(5 min)has the highest strength and a subsequent decrease in strength was observed with prolonging the bonding time and post-bond heat treatment.Furthermore,possible solidification/transformation path,segregation behavior,and formation mechanism of NSZ/ISZ evolution were discussed.

关 键 词：Ni-based superalloy TLP bonding Isothermal solidification M_(23)(C B)_(6) FIB Micropillar compression MICROHARDNESS 

分 类 号：TG146.22[一般工业技术—材料科学与工程]