A good balance between ductility and stretch formability of dilute Mg-Sn-Y sheet at room temperature

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2018-10, Vol.736, p.404-416
• Main Authors: Wang, Qinghang, Shen, Yaqun, Jiang, Bin, Tang, Aitao, Chai, Yanfu, Song, Jiangfeng, Yang, Tianhao, Huang, Guangsheng, Pan, Fusheng
• Format: Article
• Language: English
• Subjects: Annealing; Dilute Mg-Sn-Y sheet; Dilution; Ductility; Dynamic recrystallization; Extrusion; Formability; Grain boundaries; Hot rolling; Magnesium base alloys; Mechanical properties; Metal sheets; Microstructure; Prismatic slip; Recrystallization; Room temperature; Slip; Stretch formability; Tensile tests; Texture
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2018.09.011

In order to develop new magnesium alloy sheets with a good balance between ductility and stretch formability at room temperature, here we designed an Mg alloy with dilute Sn and Y and investigated the microstructure, texture, mechanical properties and stretch formability of Mg-0.4Sn-0.7Y in wt% (TW00) alloy compared with AZ31 alloy under extrusion and hot rolling-annealing conditions. We found that, after extrusion, the extruded TW00 (TW00-E) sheet exhibited a more homogeneous complete dynamic recrystallized microstructure and a splitting texture character with ~±20° tilted to the extrusion direction, compared with the extruded AZ31 (AZ31-E) sheet. After hot rolling-annealing at 400 °C, both the hot rolled annealed TW00 (TW00-RA-400) and AZ31 (AZ31-RA-400) sheets presented similar complete static recrystallized microstructures. However, significant texture weakening occurred in the TW00-RA-400 sheet rather than the AZ31-RA-400 sheet, due to static recrystallization induced by twins and grain boundaries. Tensile tests revealed that the TW00-E and TW00-RA-400 sheets with high Schmid factor (SF) for basal slip exhibited high ductility (~ 33% and ~ 32%). Simultaneously, prismatic slip and texture weakening played a significant role on decreasing r-values for the TW00-E and TW00-RA-400 sheets, respectively, which contributed to the improvement in stretch formability (~ 6.2 mm and ~ 5.4 mm) at room temperature. Therefore, we concluded that the TW00 alloy provided a bright prospect to achieve a good balance between the ductility and stretch formability at room temperature via extrusion or hot rolling-annealing.