Abstract
Micro-sized specimens were prepared from an LPSO phase of a directionally solidified Mg-Zn-Y alloy and the tensile properties of the LPSO phase were examined by using the micro-mechanical characterization technique. A directionally solidified Mg_<85>Zn_6Y_9 alloy with an LPSO phase was fabricated by using the Bridgman method. Micro-tensile specimens with a gauge section size of 20×20×50μm^3 (hereafter, DS specimens) were prepared from the directionally solidified alloy by focused ion beam (FIB) machining. The tensile direction was set to be approximately 45° from the c-axis of the LPSO phase, that is, the slip plane of the LPSO phase. Further, after applying a compressive load to the directionally solidified alloy to introduce kink bands into the LPSO phase, we prepared similar micro-tensile specimens from the kink band region (hereafter, kinked specimens). The yield stress of the DS specimen without the kink bands was 28 MPa; the specimen work-hardened moderately and then fractured after reaching the maximum stress of 51 MPa. After the tensile test, slip bands corresponding to the basal slip of the LPSO phase, were observed on the specimen surface. On the other hand, the yield strength of the kinked specimen was 65 MPa; this specimen work-hardened rapidly before reaching the maximum stress of 82 MPa. However, the plastic elongation was considerably small, and the specimen exhibited a brittle fracture. The surface observation of the kinked specimen indicated that the slip was suppressed by the kink band, thereby, causing inhomogeneous deformation.
