Evaluation of EV31A-T6 Magnesium Casting Alloy for Rotorcraft Applications

Castings offer a low cost manufacturing approach for many rotor-craft components.  Aluminum and magnesium castings are used extensively for drive system transmission housings and provide an economical means to produce complex geometries with cored passageways for oil cooling.  Other rotorcraft applications have utilized titanium, steel, and aluminum investment castings to provide an optimized geometry for specific loading applications.   A brief overview of casting components in rotorcraft applications will be presented, along with a detailed evaluation of EV31A-T6 magnesium sand casting material. 

EV31A alloy was developed by Magnesium Elektron (MEL) as a more producible alternative to WE43, and provides greater strength at temperature and corrosion resistance than traditional sand casting structural alloys such as ZE41A.   Mechanical strength evaluations were performed on welded and non-welded cast material, along with quench media variations.  Additionally, a demonstration casting was poured to evaluate the producibility aspects of a typical transmission housing.