Monotonic and Cyclic Characterization of Five Different Casting Processes on a Common Magnesium Alloy

The monotonic and cyclic behavior of five different casting processes for AZ91 magnesium alloy is evaluated through microstructure characterization and mechanical testing. A passenger car control arm was cast by squeeze cast, low pressure permanent mold, low pressure permanent mold-electricmagnetic-pump, T-mag, and ablation processes. Samples were cut from twelve locations of the control arm for microstructure characterization. The grain size, porosity fraction, and porosity size were measured via optical microscopy. Different types and sizes of defects were present in each type of casting processes. The mechanical behavior characterization included monotonic tension, and fully-reversed fatigue tests. Sources of fatigue crack initiation were quantified using scanning electron microscopy. For both monotonic and cyclic loading conditions, poor mechanical performance was directly linked to the presence of large pores, oxide films, and/or pore shrinkage clusters.© 2011 ASME