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) (Ce_(52.4)La_(26.0)Nd_(21.6)) in at. %) alloys were prepared by high-frequency induction melting in an Ar atmosphere. The microstructure and mechanical properties of the extruded alloys were investigated. The microstructure contained very small sized RE intermetallic compound particles within the a-Mg matrix and between 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 properties over those of the Mg_(96)Zn_2Y_2 alloy. Excellent tensile yield strength was obtained in the extruded Mg_(96)Zn_2Y_(1.9)M_(0.1) alloys, with a yield strength of 379 MPa at room temperature and 312 MPa at 523K, respectively. Considerable improvement was observed in the creep behavior of the Mg_(96)Zn_2Y_(1.9)M_(0.1) alloys at 473K. Extended creep life and reduced minimum creep rate were also observed.