Binder-jetting additive manufacturing of Mg alloy densified by two-step sintering process

Abstract

Difficult to effectively densify in a short time is an important issue that limits the application of magnesium (Mg) alloy fabricated by binder jetting additive manufacturing (AM) process. In this study, two-step sintering (TSS) process was utilized to improve the density of printed Mg alloy samples. Results show that the relative density, mechanical properties and corrosion resistance of the samples after different TSS process were dramatically improved in a short time. A suitable sintering temperature of first sintering step can rapidly increase the density of the samples in a short time. During the second step sintering process, little exceeding the liquidus temperature can further increase the density of the sample, but little lower than the liquidus temperature will lead to a sharp increase in grain size. The sample after sintering at 680 °C for 30 min then sintering at 610 °C for 6 h shows the highest relative density (0.995), the highest strength (394 MPa), the lowest corrosion rate (101 mm/year) and the smallest corrosion current density (60.4 μA/cm2). Compared with one-step sintering process, TTS process has higher sintering efficiency.