Grain refinement of AZ91D magnesium alloy by a new Mg-50%Al4C3 master alloy

A novel and simple method for preparing Mg-50%Al4C3 (hereafter in wt.%) master alloy has been developed by powder in-situ synthesis process under argon atmosphere. X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) results show the existence of Al4C3 particles in this master alloy. After adding 1.8% Mg-50%Al4C3 master alloy, the average grain size of alpha-Mg decreased from 360 pm to 154 mu m. Based on the DTA test results and calculation of the planar disregistry between Al4C3 and alpha-Mg, Al4C3 particles located in the central regions of magnesium grains can act as the heterogeneous nucleus of primary alpha-Mg phase. (C) 2009 Elsevier By. All rights reserved.