Magnesium Die Casting Alloy AJ62x with Superior Creep Resistance, Ductility and Die Castability

Magnesium die casting alloys for elevated temperature applications are coming of age. Several research centers and companies have been working on alloy systems based on alkaline earth and rare earth alloying additions to push the limits for the creep performance of Mg-based die casting alloys. Noranda's Mg-Al-Sr based alloys have shown superior creep performance and high-temperature performance at temperatures as high as 150-175C and stress levels of 50MPa - 70MPa. The most recent alloy formulation AJ62x (Mg-6Al-2Sr) has in addition shown excellent castability, and superior hot-tear resistance. Based on these attributes AJ62x is positioned well for applications such as transmission cases and oil pans. In this paper, the mechanical properties (creep and tensile) of AJ62x are presented. The high ductility of the AJ62Lx version is an added advantage for this alloy. Lab-scale evaluation of AJ62x shows that the alloy is more resistant to hot-tearing and cracking than all other magnesium alloys and the A380 aluminum alloy and industrial trials indicate that the alloy is highly castable. [Applications: automotive components].