Effect of Rolling Temperature on Corrosion Properties of ZK60 Magnesium Alloy

The extruded ZK60 magnesium alloy was dissolved at 400 ℃ for 24 h, and then rolled at different temperatures. The corrosion properties of ZK60, solid solution and rolled magnesium alloys at different temperatures were studied by hydrogen evolution method, weight loss method and electrochemical test method. The microstructure, corrosion products and corrosion morphology of the alloy were observed by optical microscope and scanning electron microscope, and its phase was analyzed by energy spectrum and XRD. The results show that the rolling refines the grains by dynamic recrystallization, thus improving the corrosion resistance of the alloy. The grain size, grain boundary distribution and the number of precipitated second phase in the alloy are the main factors affecting the corrosion resistance of the alloy. With the increase of rolling temperature, the recrystallized grains gradually grow, and the precipitated second phase gradually increases, which reduces the corrosion resistance of the alloy. The alloy rolled at 175 ℃ has the smallest average grain size, uniform grain boundary distribution and the best corrosion resistance.