Microstructure and mechanical properties of Mg-xY-1.5MM-0.4Zr alloys

• Published in: Journal of rare earths 2011-05, Vol.29 (5), p.454-459
• Main Author: 王军 朱秀荣 王荣 徐永东 聂景江 凌国平
• Format: Article
• Language: English
• Subjects: Age hardening; Alloys; magnesium alloy; Magnesium base alloys; Mg-Y-MM-Zr; precipitate phases; Precipitates; Precipitation; Rare earth metals; rare earths; Scanning electron microscopy; SEM; TEM; Tensile strength; 六角型; 合金; 性能; 晶粒尺寸; 硬化; 立方型
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/S1002-0721(10)60478-4

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.