Developing Zn–1.5Mg Alloy with Simultaneous Improved Strength, Ductility and Suitable Biodegradability by Rolling at Room Temperature

This study systematically investigated the influence of the microstructure evolution, mechanical properties and corrosion behaviors on Zn–1.5Mg (wt%) alloy processed by room-temperature rolling. The as-cast Zn–1.5Mg alloy consists of η -Zn matrix and η -Zn + Mg 2 Zn 11 eutectic structure. As rolling reduction increases, the average grain size of the alloy reduces from 42.9 to 1.7 μm, and the eutectic structure undergoes fragmentation and refinement, changing from a network distribution surrounding the matrix to a lamellar alternating distribution with the matrix. The ultimate tensile strength of the as-rolled alloy (80% reduction) is increased to 366 ± 3.7 MPa, along with a good elongation of 18.4% ± 2.0%. Immersion tests in Hanks’ solution indicate that the initial corrosion rate of the 80%-rolled alloy is 0.030 mm/year and finally stabilizes at 0.034 mm/year when the immersion duration is extended to 21 days. According to X-ray diffractometer and X-ray photoelectron spectroscopy analyses, Ca 3 (PO 4 ) 2 , CaCO 3 , Ca(OH) 2 , Zn 3 (PO 4 ) 2 , Zn(OH) 2 , ZnO and a small amount of MgO and MgCO 3 are the main corrosion products on the surface. Due to the microstructure refinement, the developed alloy exhibits uniform corrosion, and the corrosion morphology is dominated by pitting pits.