Influence of ultrasonic impact treatment and working current on microstructure and mechanical properties of 2219 aluminium alloy wire arc additive manufacturing parts

Ultrasonic impact treatment (UIT) is considered to solve the defects of wire arc additive manufacturing (WAAM) components such as coarse grain size, large residual stress, and poor mechanical properties. In this paper, the effects of UIT on the microstructure and mechanical properties of 2219 aluminum alloy WAAM components were systematically studied. The effect of UIT on grain size and porosity was investigated by metallographic experiments. Electron backscattering diffraction (EBSD) was used to analyze the effect of UIT on grain orientation and texture. The chemical composition and phase composition were characterized by energy dispersive spectrum (EDS) and transmission electron microscopy (TEM). The effect of UIT on mechanical properties was analyzed by tensile test. Therefore, the influence and strengthening mechanism of UIT on WAAM components are analyzed. The results show that UIT can refine the grain size and reduce porosity. In addition, UIT can increase the dislocation density, improve the surface residual stress, and distribute the precipitated phase evenly in the matrix, thus effectively improving the mechanical properties of the WAAM components. This study provides a basis for improving the quality of WAAM components, and has reference value for the application of WAAM and UIT technology, as well as the regulation of the microstructure and properties of 2219 aluminum alloy.