Microstructure features of in-situ SiC_p/6061Al in plasma arc welding by new reinforced phase

The aluminum matrix composite which reinforced by SiC_p particles was added Al-5Ti-5Si as filling material in plasma arc "in-situ" welding, and the alternating arc-ultrasonic was needed in the welding process. The microstructures at the interfaces were observed by transmission electron microscopy (TEM) and HRTEM.The results show that the sizes of all new reinforced phases become smaller, and such orientation relationships as Al₃Ti(02̄0)//Al(002̄), Al₃Ti[001]//Al[100] and AlN[100]//Al[100] are founded in the joint. There are entire-coherent interface between the Al matrix and the small new reinforced phases of Al₃Ti, AlN, Si and TiC, but no resultant production is observed along those interfaces. The Al matrix can grow along the new reinforced phases which have low-dislocation with Al, so the size of Al can be reduced. The mechanical testing results show that the maximum tensile strength of the welded joint is 92.69 MPa, which reaches the 62% of the matrix strengths.