Effect of Al Addition on As-Cast Microstructure and Mechanical Properties of Mg-5Gd Alloy

The paper discussed the effect of Al addition on microstructure characteristics and composition of second phases in Mg-5Gd alloys by using of OM, SEM-EDS and TEM-EDX. A remarkable grain refinement effect was found when a little of Al was added to the Mg-5Gd alloy. The second phase particles Mg5Gd, formed by Mg and Gd, distributed uniformly in α-Mg matrix and some clusters existed at the grain boundaries of Mg-5Gd alloy. A high melting point, hard, block-shaped phase Al3Gd, formed by Al and Gd, distributed at the grain boundaries and the amount of Al3Gd increased with the enhancement of Al content. When the content of Al exceeded 0.8%, the brickle phase Al12Mg17 was found in the Mg-5Gd-Al alloys.