Influence of Sc and Zr on the microstructure and hardness properties of A356 aluminum alloy

Aluminum alloy is widely used in the automotive and aerospace industries due to its exceptional properties, which include a high strength-to-weight ratio, excellent corrosion resistance, and the ability to increase strength via heat treatment. The Al-Si alloy group is one of the most common casting materials, chosen for its superior fluidity. However, there is potential for improvement in its mechanical properties. This study will investigate the effect of adding Sc and/or Zr secondary alloying elements on the metallurgical structure and hardness of A356 cast aluminum alloy. The addition of Sc and/or Zr reduces the grain size of A356. Furthermore, Sc also influences the structure of eutectic silicon by transforming the coarse plate-like structure into a finer fibrous one. This refinement of the grain and modification of the eutectic silicon contribute to an increase in the hardness of A356 aluminum alloy.