【摘要】 使用自制的含Sc、Ce、Be的TiB₂原位增强焊丝与4047焊丝分别对T6态SiCp/AlMMCs进行TIG焊。分析了接头的力学性能、显微组织以及断口形貌和第二相粒子分布。结果表明:2种焊丝的焊缝成型优良,4047焊丝成型更加美观;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;2种接头的HV硬度值在焊缝中心两侧近似呈对称分布,焊缝区硬度最低,平均值分别为716、600MPa,热影响区硬度的"过时效"现象明显;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;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。更多还原

【Abstract】 The TIG welding of T6 state SiCp/AlMMCs was carried by using self-made TiB₂ in situ reinforcement and 4047 welding wire as filling materials. The mechanical properties, microstructure, fracture morphology and second phase particles of T6 state SiCp/AlMMCs joints were analyzed. The results show that the weld forming of the two kinds of welding wires is excellent, and the weld of 4047 welding wire is more artistic. The SiC particles in the weld are less, there is a serious barren zone, and no obvious Al₄C₃ brittleness is found. Their microstructures are dendritic structure, but the dendritic grain of 4047 joint is coarse, while the grain of TiB₂ joint is fine, because of the refining effect of the rare earth element Sc, Ce, Be, and the TiB₂ particles distribute evenly in the weld. The hardness values of the two joints are approximately symmetrical on both sides of the center of the weld, and the hardness of the weld zone is the lowest, whose average value is 716 and 600 MPa, respectively. The ‘overaging’ phenomenon of the hardness in the heat affected zone is obvious. The tensile strength of TiB₂ joint is obviously better than that of 4047 joint, and its average strength is 171.88 MPa, which is 40.03% higher than that of 4047 joint, and it is attributed to the in-situ strengthening role of TIB₂ particles. The pores in the fracture surface of TiB₂ joint are few, which is tough-brittle mixed fracture, and there are more second phase particles in the dimple; while there are more pores in the fracture surface of the 4047 joint, which is ductile fracture, and a few second phase particles exist in the dimple.更多还原