Estimation of microstructural plastic property of die-cast Mg alloy (AZ91D) with an elevated temperature indentation

Mg17Al12 is one of intermetallic compounds in die-cast magnesium alloy (AZ91D) and will affect the macroscopic mechanical properties of AZ91D. The mechanical properties of Mg17Al12 phase is extracted by an instrumented indentation. Indentation tests on both eutectic β-Mg17Al12 phase and α-Mg matrix demonstrate that the yield stress and flow stress of Mg17Al12 phase are much larger than that of Mg matrix. In particular, its yield stress can be twice higher than that of the Mg matrix, and is more than 300 MPa. Besides, the capabilities of plastic deformation of both phases are enhanced at high temperatures. The mechanical properties of both phases as a function of temperature are obtained, and their temperature effect on the macroscopic deformation behavior is further discussed.