Microstructure, mechanical properties, and formability of 1030B Al strip manufactured by ultrasound-assisted continuous casting direct rolling

The microstructure and properties of a 1030B Al strip were improved by applying ultrasonic melt treatment (UMT) in a Hazelett continuous casting direct rolling production line. The microstructure and properties of the 1030B Al strip were investigated by scanning electron microscopy, electron backscatter diffraction, and tensile testing. Applying UMT reduced the average grain size of the as-cast sheet by more than 28.0% with respect to that of the normal samples without UMT. When UMT was applied, the rolled strip inherited the refined grains from the as-cast sheet with an average grain size smaller than 63.0 μm. Meanwhile, the dislocation density was increased by the grain refinement, dynamic recovery, and recrystallization during rolling. Accordingly, the strain-hardening rates of the rolled samples after UMT were generally higher than those of the normal samples, and the strength of the rolled strip was also improved. Furthermore, the rolled strip exhibited better formability with higher strain-hardening exponents and Erichsen index values.