Microstructure and mechanical properties of Mg-Zn-Y rolled sheet with a Mg12ZnY phase

Abstract

Ternary Mg-Zn-Y alloy sheets with several volume fractions of a Mg 12ZnY phase were prepared by hot-rolling at 623 K. Volume fraction of the Mg12ZnY phase was increased with increasing of Zn and Y contents in the Mg100-x-yZnxYy, (x = 1-6, y = 2-9 at%) alloys, and achieved more than 85% in an Mg85Zn6Y 9 alloy. (002) pole figures showed both of basal planes of the Mg12ZnY and Mg phases have a tendency to incline toward parallel to the sheet surface. However, it was considered that the formation of a basal plane texture in the Mg12ZnY phase is difficult compared with that in the Mg phase, due to a kink deformation. An Mg90.5Zn 3.25Y6.25 alloy sheet exhibited a 0.2% proof strength, an ultimate tensile strength, and an elongation of 353 MPa, 400 MPa, and 5%, respectively, at room temperature, and 279 MPa, 375 MPa, and 12%, respectively, at 523 K. Although elongation was slightly less than those in the commercial Mg sheets, the Mg90.5Zn3.25Y6.25 alloy sheet showed high strength over a wide temperature range compared to those in commercial Mg alloys. © 2010 The Japan Institute of Light Metals.