The aims of this study are to investigate the effects of Nd addition in the Mg-Al-Ca alloys on microstructure and mechanical properties.Microstructure of as-cast Mg-5Al-3Ca alloy containing Nd consists ofα-Mg matrix, eutectic phase and Al-Nd rich intermetallic compound.As Nd addition was increased,α-Mg matrix morphology was changed from dendritic to equiaxed grains and average value of grain size was decreased.Nd addition to Mg-5Al-3Ca based alloys resulted in the formation of Al-Nd rich intermetallic compounds at grain boundary andα-Mg matrix grains.And these Al-Nd rich intermetallic compounds were dispersed homogeneously.In these alloys,two kinds of eutectic phases were observed,i.e.coarse irregular-shape structure at grain boundary and fine needle-shape structure in theα-Mg matrix grain.It is found that the ultimate strength showed the maximum value of 271 MPa at Mg-5Al-3Ca-2Nd alloy and elongation was decreased as the addition of Nd was increased. The aims of this study are to investigate the effects of Nd addition in the Mg-Al-Ca alloys on microstructure and mechanical properties. Microstructure of as-cast Mg-5Al-3Ca alloy containing Nd consists of α-Mg matrix, eutectic phase and Al Nd addition was increased, α-Mg matrix morphology changed from dendritic to equiaxed grains and average value of grain size was decreased. Nd addition to Mg-5Al-3Ca based alloys resulted in the formation of Al- Nd rich intermetallic compounds at grain boundary and α-Mg matrix grains. And these Al-Nd rich intermetallic compounds were dispersed homogeneously.In these alloys, two kinds of eutectic phases were observed, iecoarse irregular-shape structure at grain boundary and fine needle- shape structure in theα-Mg matrix grain. It is found that the ultimate strength showed the maximum value of 271 MPa at Mg-5Al-3Ca-2Nd alloy and elongation decreased decreased as the addition of Nd was increased.