Influence of twin roll casting and differential speed rolling on microstructure and tensile properties in magnesium alloy sheets

Abstract

Twin-roll casting (TRC) process combines casting and hot rolling into a single step, having an advantage of one-step processing of flat rolled products. Besides being such a cost-effective process, TRC also has a beneficial effect on microstructure such as reducing segregation, improving inclusion size distribution, refining microstructural and textural homogeneity. However, conventional equal speed rolling (ESR) of TRC magnesium alloy strip preserves a strong basal texture as often found in the rolling of conventional cast ingot (IC). The ductility of magnesium alloys is strongly affected by the texture. Thus, it is important to control the texture during processing for improvement of ductility at room temperature during sequential processing. Recently it has been reported that differential speed rolling (DSR) is effective for improving tensile elongation and formability of magnesium alloys by reducing the intensity of basal texture. Thus, it is of great interest to combine TRC and DSR technique for more efficient production of magnesium alloy sheet with improved ductility. The present paper reports the comparison of microstructure and mechanical properties of AM31 alloy fabricated by TRC/IC followed by DSR/ESR.