The atmospheric corrosion behaviour of peak aged Mg-5Y-7Gd-1Nd-0?5Zr alloys in typical land (Beijing) and marine (Qingdao) environments were investigated by optical microscopy, SEM and X-ray diffraction. The weight loss rates and residual mechanical properties were analysed. The atmospheric corrosion rates of specimens in a typical marine environment were higher than those in land environment. The results demonstrated that temperature, relative humidity and inorganic salts at field exposed sites played an important role in atmospheric corrosion behaviours. The results of our investigation may find wider applications for Mg-rare earth alloys in atmospheric environments.

The hot deformation behavior of Mg-12Gd-1MM-0.6Zr (wt.%) magnesium alloy was tested by Gleeble-1500D hot simulator with reduction of 60% and strain rates from 0.001 to 1 s−1 at the temperature range from 753 to 793 K. The results show that the flow stress is influenced by both, temperatures and strain rates. At constant temperatures, flow stress is increased with strain rate, while at constant strain rates, it decreased with temperature. The constitutive equation of Mg-12Gd-1MM-0.6Zr alloy during hot compression was constructed by the linear regression analysis. Average activation energy and stress exponent were 227.94 kJ/mol and 2.87, respectively. The processing map was plotted and analyzed via the dynamic material model. The most proper ranges for hot deformation temperature and strain rate were found to be 763 to 783 K and 0.01 to 0.1 s−1, respectively.

In this paper, with the help of optical microscope, X-ray diffraction, scanning electron microscope and mechanical testing machine, the microstructures of ZT63-xCu (x=0,0.5,1.0,1.5wt.%) magnesium alloys were investigated and their mechanical properties were explored. It was found that the structure of as-cast alloys presented a typical dendrite morphology. The eutectic structure was refined by the addition of a certain amount of Cu, When Cu content continued to increase, the volume fraction of the eutectic structure increased and its continuity enhanced. The alloy without Cu addition was composed of α -Mg, MgZn2 and Mg2Sn phases. With the addition of Cu elements, MgZnCu phase was formed in the alloy, in addition to α-Mg, MgZn2 and Mg2Sn phases. With the increase of Cu content, the volume fraction of MgZnCu phase increased, and the proportion of MgZn2 phase gradually decreased. ZT63 alloy had the best matching of mechanical properties, its tensile strength and yield strength were 231Mpa and 80Mpa respectively, and the elongation reached 14.5%. With the increase of Cu, the mechanical properties of the alloys declined. When the Cu content is 1.5wt.%, tensile strength of the alloy decreased to 174Mpa, and the elongation was only 7%. The reduction of mechanical properties was related to the increase of MgZnCu phase.