The structure and mechanical properties of high-strength aluminum alloys fabricated with wire arc additive manufacturing

Abstract

In this study, optimized wire arc additive manufacturing (WAAM) process parameters were used to fabricate 2319 aluminum alloy samples. The microstructure and mechanical properties of printed samples were carefully studied. The results showed that 2319 aluminum alloy samples manufactured by WAAM had good surface quality, and no metallurgical defects such as cracks or incomplete fusion were found in the samples. The printed 2319 aluminum alloy sample was mainly composed of the matrix phase ɑ (Al) and strengthening phase θ (Al2Cu). It was found that the quantity and distribution of strengthening phases were affected by the heat treatment process. Compared to the T4-state heat treatment, the distribution of the strengthening phase a (Al2Cu) was more uniform and its quantity was significantly increased after the T6-state (530 °C/20 h+170 °C/18 h) heat treatment. As a result, the results showed that its transverse tensile strength was 436.3 MPa and the elongation was 12%. Meanwhile, the longitudinal tensile strength was 376.3 MPa, and the elongation was 8.5%, which was much higher than the performance of casted 2319 aluminum alloy. The fracture surfaces of 2319 samples had small and uniform dimples, which indicated that they belonged to ductile fracture.