Vacuum brazing of GH99 superalloy using graphene reinforced BNi-2 composite filler

作     者：Duo Liu Yanyu Song Bin Shi Qi Zhang Xiaoguo Song Hongwei Niu Jicai Feng 

作者机构：State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Shandong Provincial Key Laboratory of Special Welding Technology Harbin Institute of Technology at Weihai 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2018年第34卷第10期

页      面：1843-1850页

核心收录：

学科分类：080503[工学-材料加工工程] 0817[工学-化学工程与技术] 0806[工学-冶金工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 0802[工学-机械工程] 0801[工学-力学（可授工学、理学学位）] 0702[理学-物理学] 080201[工学-机械制造及其自动化] 

基　　金：supported financially by the National Natural Science Foundation of China(Nos.51505105,51775138 and U1537206) the International Science&Technology Cooperation Program of China(No.2015DFA50470) the Key Research&Development program of Shandong Province(No.2017GGX40103) 

主　　题：Graphene GH99 superalloy Brazing Microstructure Mechanical properties 

摘      要：A novel graphene reinforced BNi-2 composite filler was developed for brazing GH99 superalloy. The interracial microstructure of brazed joints was analyzed by field emission scanning electron microscope and a transmission electron microscope. The effects of graphene addition on the microstructure evolu-tion and mechanical properties of brazed joints were investigated, and the strengthening mechanism of graphene was analyzed. The results revealed that due to the addition of graphene, M23（C,B）6 compounds were synthesized in the y solid solution and brittle boride precipitates near the brazing seam decreased. Graphene was effective in retarding solute atoms diffusion thus impeding the precipitation of borides. Furthermore, the low coefficient of thermal expansion （CTE） of graphene was conducive to relieve stress concentration of the brazed joints during the cooling process. The shear strengths of brazed joints were significantly improved by exerting the strengthening effect of graphene. The maximum shear strengths of the brazed joints were 410.4 MPa and 329.7 MPa at room temperature and 800 ℃, respectively.