SiCp/AlMMCs填充含Sc、Ce、Be的TiB2原位增强焊丝与4047焊丝的TIG焊研究

使用自制的含Sc、Ce、Be的TiB₂原位增强与4047焊丝为填充材料对T6态SiCp/AlMMCs 进行TIG焊,对接头的力学性能、显微组织以及断口形貌和第二相粒子进行分析。结果表明：两种焊丝焊接该种材料的焊缝成型优良,4047焊丝成型更加美观;TiB₂接头的抗拉强度明显优于ER4047接头,平均强度达到171.88MPa,相对于4047接头强度提高40.03%,TiB₂粒子起到了原位增强的作用;两种接头的硬度值在焊缝中心近似呈对称分布,焊缝区硬度最低,平均值分别为：71.65HV、60.02HV,热影响区硬度的“过时效”现象明显;焊缝中SiC颗粒较少,存在严重贫瘠区 ,未发现明显的Al₄C₃脆性物;显微组织都为枝晶组织,但4047接头焊缝枝晶粗大,TiB₂接头焊缝晶粒细小,稀土元素Sc、Ce、Be起到了细化晶粒的作用,且TiB₂粒子在焊缝中分布均匀;TiB2接头断口中气孔较少,为韧-脆性混合性断裂,韧窝中第二相粒子较多;4047接头断口中气孔较多,为韧性断裂,韧窝中第二相粒子较少。

Study on TIG Welding of TiB2 in situ reinforced Wire and 4047 Wire filled with Sc,Ce,Be filled with SiCp/AlMMCs

The mechanical properties, microstructure, fracture morphology and second phase particles of T6 state SiCp/AlMMCs were analyzed by using self-made TiB2 in situ reinforcement and 4047 welding wire as filling materials for TIG welding of T6 state SiCp/AlMMCs. The results show that the weld forming of the two kinds of welding wires is excellent, and the 4047 welding wire is more beautiful, and the tensile strength of TiB₂ joint is obviously better than that of ER4047 joint, and the average strength is 171.88 MPA, which is 40.03% higher than that of 4047 joint. TIB₂ particles play an in-situ strengthening role. The hardness values of the two joints are approximately symmetrical in the center of the weld, and the hardness of the weld zone is the lowest, the average value is 71.65HV,60.02HV. the "overaging" phenomenon of the hardness in the heat affected zone is obvious, the SiC particles in the weld are less, there is a serious barren zone, and no obvious Al₄C₃ brittleness is found. The microstructure is dendritic structure, but the dendritic grain of 4047 joint is coarse, the grain size of TiB₂ joint is fine, the rare earth element Sc,Ce,Be plays the role of refining grain, and the TiB₂ particles are evenly distributed in the weld, and the pores in the fracture surface of TiB₂ joint are few, which is tough. The brittle mixed fracture shows that there are more particles in the second phase in the dimple, and there are more pores in the fracture surface of the 4047 joint, which is ductile fracture, and the second phase particles in the dimple are less.