Research On Squeeze Casting Of High Toughness Magnesium Alloys

As the"green"structure material for the 21st century, magnesium alloys possess the superiority in terms of reducing energy consumption, increasing the energy efficiency, lessening the pollution with the advantage of light, specific mechanical properties, good damping etc.The commonly used AM60B is a type of Mg alloys of high toughness, which, in turn, makes the alloy promising for wheel application. However, the relatively lower strength is hard to meet the need of wheel and engine-cradle for an idea combination of strength and toughness, which, in turn, limits the applications of MG alloys for performance critical applications.With Am60B as master material and squeeze casting as processing method, the microstructure and mechanical properties of squeeze cast AM60B alloy, the effect of Al, Zn and heat treatment on the microstructure and mechanical properties were investigated in the present study to provide a base for alloy development and processing control of squeeze casting of Mg alloys.The experimental results indicate that, the use of squeeze casting technique obviously refined the solidification structure, enhances the mechanical performance of the alloy. With the increase of Al concentration, the ultimate tensile strength of AM Mg alloy increases while the elongation decreases dramatically. With the increase of Zn concentration, the ultimate tensile strength and elongation of the alloy decrease, while the yield strength is improved slightly. T61 heat treatment changes the morphology ofγ-Mg17Al12 into nodular and short plates at grain boundary and fine precipitation within the grain, which consequently improves the ultimate strength and elongation, but remains the yielding strength unchanged.