Amorphous magnesium alloy with high corrosion resistance fabricated by laser powder bed fusion

Mg alloy suffers from poor corrosion resistance due to the corrosive microdefects including grain boundary, precipitates, and composition segregation, which lead to interfacial corrosion and galvanic corrosion, limiting the orthopedic application. In this work, an amorphous Mg-Zn-Ca alloy is fabricated by laser powder bed fusion (LPBF). LPBF provides a large degree of undercooling to achieve rapid solidification, which inhibits the nucleation and growth of the alloy and obtains the amorphous structure. Moreover, LPBF can prepare Mg alloy with complex porous internal structures and personalized shapes according to implant requirements. The results show the Mg-Zn-Ca alloy fabricated by LPBF is mainly composed of amorphous phases with chemical homogeneity. The amorphous alloy has excellent corrosion resistance, and its corrosion rate is 0.35 mm•y−1, which is within the ideal range of degradation rates for human bone implants. The corrosion product film is dense and uniform due to the formation of ZnO and Ca3(PO4)2 and uniform corrosion, preventing further corrosion and protecting the alloy matrix, thus reducing the degradation rate of the amorphous alloy. The amorphous alloy prepared by LPBF is expected to promote the application of Mg alloy in orthopedics.