Microstructure and mechanical properties of low-pressure spray-formed Zn-rich aluminum alloy

In this study, a low-pressure spray forming technology was proposed to prepare 7055Al alloys with the characteristic of high strength and plasticity. Finer equiaxed grains were observed in the spray formed 7055Al alloy and the size of these grains was about 10~50 µm, which was much smaller than that of as-cast alloy. The experiment also saw a significant alleviation in the segregation of alloying elements in the spray formed 7055Al alloys, and that the alloying elements had more homogeneous distribution in the spray formed materials. The yield strength, ultimate tensile strength and elongation of the spray formed materials followed by hot extrusion and heat treatment were 651.9 MPa, 692.5 MPa and 7.7%, respectively. Compared with as-cast 7055Al alloys under the same condition, the above-mentioned performance parameters were increased by 7.3%, 9.9% and 48.1%, respectively. There was a significant improvement in both strength and plasticity of spray formed materials, which indicates the low-pressure spray forming technology proposed in this study to be a potential preparation technology for high-quality metal alloys.