OS0302 Mg-Zn-Y-RE合金の組織と機械的性質に及ぼす希土類元素添加の影響(非立方晶型金属材料の変形現象とそのモデル化,オーガナイズドセッション)

概要

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Mg_<97>Zn_1Y_1RE_1 (RE=La, Ce, Nd and Sm, at. %) alloys were prepared by high-frequency induction melting in an Ar atmosphere. The rods were extruded with an extrusion ratio of 10 at 623K and a ram speed of 2.5mm s^<-1>. The microstructure and mechanical properties of the extruded alloys were investigated. Mg_<97>Zn_1Y_1Nd_1 and Mg_<97>Zn_1Y_1Sm_1 alloys consisted of just 2 phases of α-Mg and Mg-RE intermetallic compound. The Mg_<97>Zn_1Y_1La_1 and Mg_<97>Zn_1Y_1Ce_1 alloys consisted of 3 phases of α-Mg, Mg-RE intermetallic compound and Mg_<12>ZnY corresponding to a long period stacking ordered (LPSO) structure. Specially, after extrusion, the Mg_<97>Zn_1RE_1 alloys with α-Mg, Mg-RE intermetallic compound and LPSO phase had the stratified structure. The Mg_<97>Zn_1Y_1RE_1 alloys with LPSO phase exhibited higher mechanical properties than the Mg_<97>Zn_1Y_1RE_1 alloys without LPSO phase. The yield strength and ultimate tensile strength at room temperature of Mg_<97>Zn_1Y_1La_1 and Mg_<97>Zn_1Y_1Ce_1 alloys consisting 3 phases were 390-393 MPa and 439-442 MPa, respectively. Their ultimate tensile strength at the elevated temperature of 473 K was more than 330 MPa.
2009-07-24