Heat Resistant Magnesium Alloys for Power-Train Applications 2001-01-0424

A new family of heat-resistant alloys has been developed by Noranda Inc. This new alloy system is based on the Mg-Al-Sr system. The three compositions evaluated in this system, namely (Mg-Al-Sr)1 (Mg-Al-Sr)2 and Mg-Al-Sr)3, hereafter referred A1, A2 and A3 demonstrate excellent creep and mechanical properties in the 150°C to 175°C temperature range. They possess excellent salt-spray corrosion resistance, comparable to AZ91D and AM type alloys and is superior to AS41 and the aluminum alloy A380. This combination of properties makes these alloys suitable for automatic transmission casing, crankcase, oil pump body, oil pan, belt pulley, cylinder cover, engine fan applications as well as other under-the-hood components. The present paper summarises the mechanical and corrosion properties and die casting of the alloys. The boit-load-retention test results are also discussed. Diecastability has been improved using a modified alloy composition (A4).