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Age hardening,microstructure and mechanical properties of Mg-xY-1.5MM-0.4Zr (x=0,2,4,6 wt.%) alloys (MM represents Ce-based misch-metal) were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the formed precipitates being responsible for age hardening changed from fine hexagonal-shaped equilibrium Mg12MM phase to metastable β’ phase with bco crystal structure when Y was added into Mg-1.5MM-0.4Zr alloy,and the volume fraction of precipitate phases also increased. With the increase of Y content in Mg-Y-1.5MM-0.4Zr alloys,it was found that the age hardening was enhanced,the grain sizes became finer and the tensile strength was improved. The cubic-shaped β-Mg24Y5 precipitate phases were observed at grain boundaries in Mg-6Y-1.5MM-0.4Zr alloy. It was suggested that the distribution of prismatic shaped β’ phases and cubic shaped β-Mg24Y5 precipitate phases in Mg matrix might account for the remarkable enhancement of tensile strength of Mg-Y-MM-Zr alloy. It was shown that the Mg-6Y-1.5MM-0.4Zr alloy was with maximum tensile strength at aged-peak hardness,UTS of 280 MPa at room temperature and 223 MPa at 250 oC,respectively.
Age hardening, microstructure and mechanical properties of Mg-xY-1.5MM-0.4Zr (x = 0, 2, 4, 6 wt.%) Alloys (MM represents Ce- based misch-metal) were investigated by scanning electron microscopy ) and transmission electron microscopy (TEM). The results showed that the precipitated being being responsible for age hardening changed from fine hexagonal-shaped equilibrium Mg12MM phase to metastable β ’phase with bco crystal structure when Y was added into Mg-1.5MM-0.4 Zr alloy, and the volume fraction of precipitations phases also increased. With the increase of Y content in Mg-Y-1.5MM-0.4Zr alloys, it was found that the age hardening was enhanced, the grain sizes became finer and the tensile strength was was. The was-formed β-Mg24Y5 precipitate phases were observed at grain boundaries in Mg-6Y-1.5MM-0.4Zr alloy. It was suggested that the distribution of prismatic shaped β ’phases and cubic shaped β-Mg24Y5 precipitate phases in Mg matrix might account for the remarkable enhancement of ten The strength of Mg-Y-MM-Zr alloy. It was shown that the Mg-6Y-1.5MM-0.4Zr alloy was with maximum tensile strength at aged-peak hardness, UTS of 280 MPa at room temperature and 223 MPa at 250 oC, respectively.