Effect of fine-grained raw material addition on microstructure refinement and tensile properties in horizontal continuous casting Al–12%Si alloy billets

Horizontal continuous casting (HCC) Al–12%Si alloy billets were prepared using fine-grained Al–12%Si as a raw material. The influence of this fine-grained raw material on the microstructure and tensile properties was studied. The uniformity of the HCC Al–12%Si alloy billets was also analyzed. The results show that the fine-grained raw material can effectively reduce macrosegregation and make both the α-Al and eutectic silicon much finer. The ultimate tensile strength and elongation clearly increased with an addition of 30% fine-grained raw material compared to the HCC alloy billets with no addition of fine-grained raw material. However a small decrease nonetheless occurred after an addition of fine-grained raw material up to 50%.

Research highlights
► Fine-grained Al-12%Si raw material prepared by rapid solidification can be used as a refiner.
► This raw material can refine the microstructure of HCC Al-12%Si alloy billets.
► It can also enhance the tensile properties of HCC Al-12%Si alloy billets.
► The microstructure of HCC Al-12%Si alloy billets becomes much more uniform with raw material.