Microstructure, mechanical and corrosion properties of magnesium alloy bone plate treated by high-energy shot peening
(1. School of Mechanical Engineering, University of Jinan, Ji’nan 250022, China;
2. Department of Orthopedics, The 960th Hospital of the People’s Liberation Army, Ji’nan 250031, China)
2. Department of Orthopedics, The 960th Hospital of the People’s Liberation Army, Ji’nan 250031, China)
Abstract: To enhance the mechanical properties and corrosion resistance of magnesium alloys, high-energy shot peening (HESP) was used. According to the results, the in-situ surface nanocrystallization (ISNC) microstructure was fabricated on the magnesium alloy surface, and its formation mechanism was the coordination among twins, dislocations, subgrain boundary formation and dynamic recrystallization. Under the released surface stress of sample, the residual compressive stress and microhardness rose, thus enhancing compactness of the surface passivation film Mg(OH)2. Besides, the corrosion rate dropped by 29.2% in maximum. In the polarization curve, the maximum positive shift of the corrosion potential of sample was 203 mV, and the corrosion current density decreased by 31.25% in maximum. Moreover, the compression resistance and bending resistance of the bone plate were enhanced, and the maximum improvement rates were 18.2% and 23.1%, respectively. Accordingly, HESP significantly enhanced mechanical properties and corrosion resistance of magnesium alloys.
Key words: magnesium alloys; high energy shot peening; in-situ surface nanocrystallization; mechanical properties; corrosion properties