Comparative Analysis of Microstructure and Properties Between Twin-Roll Casting AZ31B Alloy and Advanced Mg-Mn-Al-Zn Alloy

Abstract

Multiple precision rolling passes are necessary to address issues in twin-roll cast magnesium alloy slabs, such as uneven microstructure, central segregation, and porosity. However, this process can lead to strong basal texture and reduced controllability. To enhance the efficiency of cast-rolled magnesium alloys and highlight the advantages of concise casting and rolling, we conducted comparative evaluations of edge cracking, microstructural consistency, and room-temperature mechanical properties of advanced Mg-Mn-Al-Zn alloys with varying initial thicknesses against the conventional AZ31B alloy. The analysis considers different rolling passes, temperatures, and initial thicknesses. Results indicate that Mg-Mn-Al-Zn alloys exhibit a broader initial rolling temperature range, fewer crack defects, and improved sheet profile and flatness compared to AZ31B. At 300–350°C, Mg-Mn-Al-Zn alloys show enhanced grain refinement and microstructural homogeneity. Both alloys display similar post-rolling tensile properties at room temperature, with approximately 1% variance in peak elongation. Mg-Mn-Al-Zn alloys demonstrate reduced anisotropy compared to AZ31B. With fewer rolling passes, Mg-Mn-Al-Zn alloys slightly outperform AZ31B in mechanical characteristics and ductility. Consequently, Mg-Mn-Al-Zn alloys show improved efficiency in subsequent precision rolling processes compared to traditional cast-rolled AZ31B magnesium alloy, offering potential advantages in industrial applications.