CAST MAGNESIUM ALLOYS FOR ELEVATED-TEMPERATURE APPLICATIONS

The alloy development, microstructure, properties and uses of cast magnesium alloys for elevated temperature applications are reviewed. The alloying principles and strengthening mechanisms of magnesium are discussed to identify the potential alloy systems for elevated temperature applications in automotive and aerospace industries. It is concluded that the Mg-Zr family of sand cast alloys exhibit adequate mechanical properties at both ambient and elevated temperatures for aerospace applications, and Ca-modified sand cast AS41 alloy might provide a cost-effective alternative for the Zr-containing alloys. For diecasting applications, no current alloy systems meets the requirements of good high temperature properties, acceptable castability and low cost for critical automotive components, future development is especially needed in this area. Development of dispersion strengthened magnesium alloys and improvement of current Mg-AI-RE and Mg-Al-Si systems are the potential routes to expand diecast magnesium alloys to elevated temperature applications.