MICROSTRUCTURE AND MECHANICAL PROPERTIES OF Mg-Zn-Y-M (M: MIXED RE) ALLOYS WITH LPSO PHASE

摘要

Mg_(96)Zn_2Y_(1.9)M_(0.1) (M=Monazite base mixed Rare Earth (RE)(Ce52.4La26.0Nd21.6) in at. %) alloys were prepared by highfrequencyinduction melting in an Ar atmosphere. Themicrostructure and mechanical properties of the extruded alloyswere investigated. The microstructure contained very small sizedRE intermetallic compound particles within the a-Mg matrix andbetween the LPSO intergranular phase in the Mg_(96)Zn_2Y_(1.9)M_(0.1)alloys. The presence of the RE compound in the Mg_(96)Zn_2Y_(1.9)M_(0.1)alloy was responsible for its improved tensile and creep propertiesover those of the Mg_(96)Zn_2Y_2 alloy. Excellent tensile yield strengthwas obtained in the extruded Mg96Zn2Y1.9M0.1 alloys, with a yieldstrength of 379 Mpa at room temperature and 312 Mpa at 523K,respectively. Considerable improvement was observed in thecreep behavior of the Mg_(96)Zn_2Y_(1.9)M_(0.1) alloys at 473K. Extendedcreep life and reduced minimum creep rate were also observed.