Dependence of microstructure and mechanical properties on solidification condition of directionally solidified Zn-55Al-1.6Si alloys

In this study, directional solidification was utilized to explore the relationship between microstructure, mechanical properties, and withdrawal speeds of Zn-55Al-1.6Si alloys. In order to assess the characteristics of Zn-55Al-1.6Si alloys, both the microstructure and mechanical properties were thoroughly analyzed. This involved conducting room temperature tensile tests on samples with different withdrawal speeds (5, 10, 100, 200, and 400 µm·s−1). The results reveal that both the as-cast alloy and samples after directional solidification are composed of zinc, aluminum and silicon phases. As the withdrawal speed increases, an evident decrease in the size of the primary dendrites is observed. The results of tensile experiments show that Zn-55Al-1.6Si alloys after directional solidification exhibit brittle fracture characteristics, both the tensile strength and elongation of the alloys increase with withdrawal speed.