Microstructure and mechanical properties of 7075/5356 aluminum alloy laminated composite fabricated by wire arc additive manufacturing

•A novel 7075/5356 aluminum alloy layered composite was produced via arc wire additive manufacturing.•An interlayer region was formed between 7075 and 5356 with gradient change in alloying elements and microhardness.•Excellent comprehensive mechanical properties with high tensile strength and high plasticity were achieved. A 7075/5356 aluminum alloy laminated composite was fabricated by alternately depositing a 7075 wire and a 5356 wire layer by layer using wire arc additive manufacturing (WAAM). The microstructure and mechanical properties of the produced components under as-deposited and heat-treated conditions were investigated. The results revealed that the grain morphology of the specimen was mainly composed of equiaxed grains in each layer, while the grain size of the interlayer region was reduced due to the heterogeneous nucleation relying on the partially remelted previous layer. Moreover, a reduced amount of second phase was observed due to decreased Zn and Cu alloying elements content in this region, which resulted in a gradient change in microhardness distribution. The tensile strength and elongation of the heat-treated samples in vertical and horizontal directions were 321 MPa, 10.12 %, and 377 MPa, 9.72 %, respectively. The results indicated good comprehensive mechanical properties, which is promising for further application of WAAM fabricated laminated metal composite.