Effect of trace Zr and V on 3D morphology of Fe-rich phase and mechanical properties in recycled Al-Mg-Si alloy
摘要
Trace amounts of Zr and V can increase the recrystallization temperature of Al-Mg-Si wrought aluminum alloys, which is expected to regulate the recrystallization grain. In this paper, trace amounts of V and Zr were added to recycled Al-Mg-Si alloys, and their effects on the microstructure and mechanical properties of the cast alloys were studied by scanning electron microscopy (SEM) and synchrotron radiation X-ray tomography (SRXT). The results show that the addition of Zr significantly increases the grain sizes due to the “Zr poisoning”; V addition has no significant effect on the grain size. The morphology of Fe-rich phase gradually changes from the large Chinese-script shape to the fine short rod and curved long strip shape, and the distribution uniformity is improved with the combined addition of V and Zr. The three-dimensional (3D) morphology of Fe-rich phase includes granular, short rod-like, simple branch and multi-branch structures. The individual addition of V and Zr has no significant effect on the morphology of Fe-rich phase; but the combined addition of V and Zr significantly increases the number and volume fraction of Fe-rich phase with small size (diameter ≤15 µm), the number of branches in the largest Fe-rich phase is significantly reduced, resulting in the improvement of elongation. This work provides a theoretical basis for the development of new recycled Al-Mg-Si alloys in industrial application.