Tensile Behaviour and Microstructure of Permanent Mould Cast Magnesium Alloy AJ62 Subject to Corrosion

AJ62, containing notable amounts of strontium, exhibits a microstructure unique among aluminum-manganese based magnesium alloys. The benefit is improved high temperature mechanical performance among magnesium alloys, which are not known for this trait. Capacity for high temperature application makes AJ62 the focus of much research. The high temperature properties, coupled with the high strength to weight ratios of magnesium alloys, promise lightweight powertrain components for the automotive industry to lower fuel consumption, reduce emissions, and improve performance. Castability of the alloy is demonstrated by its adaptation to the gravity-fed permanent mould casting process. Influential characteristics of its solidified microstructures are investigated and related to tensile and corrosion response, both independently and combined. A fine microstructure with good interdendritic eutectic phase continuity is favourable for mechanical and electrochemical properties. A recommendation for processing of the alloy is to target the benefits of a high cooling rate