A microfracture testing technique was used to examine the fracture properties of a long-period stacking ordered (LPSO) phase in Mg-Zn-Y alloys. Micro-sized cantilever specimens composed of the LPSO phase with dimensions of 10 x 20 x 50 μm3 were selectively prepared from a Mg88Zn5Y7 alloy by focused ion beam (FIB) machining. Further, notches with a width of 0.5 pm and a depth of 5 pm were introduced into the micro-sized specimens. Microfracture tests were performed on the micro-sized specimens using a mechanical testing machine. The fracture toughness values (KQ) of the LPSO phase were 1.2-3.0 MPam112. Transmission electron microscopy (TEM) observation indicated that the KQvalues were dependent on crack orientation in the LPSO phase, and higher Kvalues were obtained when crack propagation was parallel to the c-axis of the LPSO phase. This suggests that controlling LPSO phase orientation effectively improves fracture toughness in Mg-Zn-Y alloys.Proc. Mg2012: 9th International Conference on Magnesium Alloys and their Applications,(2012),pp.743-748.Proc. Mg2012: 9th International Conference on Magnesium Alloys and their Applications,JULY 8-12. Vancouver, BC Canadaconference pape
