Magnesium alloys currently used in automotive applications and based on the Mg-Al-Zn system have some limitations particularly in respect of elevated temperature performance.
Recently developed alloys based on the Mg-Zn-Cu system offer a number of advantages over those based on the Mg-Al-Zn system and alloy compositions in the former can be adapted to meet specific requirements; the properties of a number of these are described.
For sand and permanent mould cast applications alloys offering improved castability, soundness and better temperature resistance are described. In the wrought form compositions offering room temperature strength higher than that of any currently available magnesium alloy coupled with good elevated temperature strength have been developed. While encouraging results have been obtained on alloys designed for die castings, more work is required, particularly in conjunction with a ‘Pore Free’ technique to permit beat treatable castings to be produced and to fully utilise the capabilities of the alloy system.