Research of the microstructure, mechanical property and corrosion behaviours of Mg–Y–Zn–Mn(–Mo) alloy with solution treatment

Abstract

To develop a biomedical magnesium alloy with desirable mechanical properties and corrosion resistance, Mg-6Zn-8.16Y-2.02Mn and Mg-6Zn-8.16Y-2.02Mn-0.3Mo alloy were prepared. Then the alloys were solution-treated at 500°C for 40 h and cooled in the furnace. The results showed that partly 18R-long-period stacking ordered (LPSO) phase transformed to 14H-LPSO phase during solid-solution treatment. The hollowed-out W phase vanished and spherical W phase was formed. And the volume fraction of 18R-LPSO and the average size of the spherical W phase particles were reduced. Corrosion behaviour of the alloy in Hank's solution under each condition was studied by immersion test and electrochemical test. The solution-treated Mg-6Zn-8.16Y-2.02Mn-0.3Mo alloy exhibited the best mechanical property (ultimate tensile strength, UTS 270 MPa and elongation, EL 23%) and corrosion resistance (P W 1.03 mm/year and I corr 0.20 mm/year) due to fine and homogeneous microstructure.