Vacuum brazing of GH99 superalloy using graphene reinforced BNi-2 composite filler
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2018年第10期
论文作者：Duo Liu Yanyu Song Bin Shi Qi Zhang Xiaoguo Song Hongwei Niu Jicai Feng
文章页码：1843 - 1850
摘 要：A novel graphene reinforced BNi-2 composite filler was developed for brazing GH99 superalloy. The interfacial 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 evolution 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 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?C, respectively.
Duo Liu1,2，Yanyu Song2，Bin Shi2，Qi Zhang2，Xiaoguo Song1,2，Hongwei Niu2，Jicai Feng1,2
1. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology2. Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai
摘 要：A novel graphene reinforced BNi-2 composite filler was developed for brazing GH99 superalloy. The interfacial 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 evolution 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 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?C, respectively.
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