Deformation Behavior of Mg-Ni-Y Alloy with Long Period Stacking Ordered Phase

Abstract

Microstructures of the long period stacking ordered (LPSO) phase deformed by compression test or rolling at room temperature were investigated. The Mg85Ni6Y9 (at.%) alloy was composed mostly of plate-type phase with 10H-type LPSO structure. The Mg85Ni6Y9 alloy exhibited compression yield stress of 365 MPa and fracture strain of 30 % at room temperature. After compression test with applied stress of 25 %, a bend, delamination between basal planes and crack initiation at boundary of the LPSO phase were observed. From these microstructural features, it was considered that the deformation of the LPSO phase significantly influenced by a kink deformation. The Mg85Ni6Y9 alloy could be rolled with 30 % reduction at room temperature. The kink deformation was frequently observed in the LPSO phase of the alloy sheet. The basal plane texture was formed in plane sheet of the alloy sheet. However, it was more difficult to form basal plane texture in the LPSO phase than in the pure-Mg due to introduce the kink deformation. Therefore, it was considered that better rollability of the Mg85Ni6Y9 alloy compared with the pure-Mg was brought for the kink deformation.