Mechanical and corrosion performance of Mg alloy via 3DP by full liquid phase sintering

Abstract

Three dimensional printing (3DP) additive manufacturing(AM) of magnesium(Mg) alloys is difficult to densify by conventional sintering process which limits its application. In this study, a novel 3DP sintering process with full liquid was utilized to improve performance of Mg alloy. Mg alloy powders were shaped at room temperature with water-based binder, and formed the MgO net-like framework at 90 °C in air atmosphere, then sintered over the liquidus temperature under the Ar atmosphere. The results show that a large amount of liquid alloy can effectively improve the density of the sample by filling the pores and mass transferring, the MgO net-like framework can effectively maintain the original shape of the parts. Density, microstructural, mechanical and corrosion properties of the parts were investigated after sintered at 620 °C for 5, 8, 10 and 12 h. The results indicated an improvement of properties with increasing in sintering time. Swelling phenomenon was not observed in this sintering temperature. The net-like framework structure might prevent the swelling caused by liquid phase flow too. The parts after sintering for 12 h at 620 °C show the remarkable relative density (97.8%), ultimate compressive strength (~354 MPa), and mass loss rate in 25 °C is 139 mm / year.