The metastable-phase precipitates which appear at the peak condition of hardness in an Al-0.83 at%Mg-0.4 at%Si alloy were investigated, using a combination of Vickers microhardness tests, DSC calorimetry, and field-emission STEM observations with EDX analyses. EDX and elemental mapping revealed that both Si-rich and Mg-Si precipitates with needle-shapes were present. EDX analysis showed that needle-shaped β″precipitates protruding from the specimen foils were composed mainly of Si. The present results on structures, compositions and thermal stabilities of the precipitates suggest that Si-rich precipitates co-exist with complex Mg-Si precipitates also of needle-shape.
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry