Metals (Mar 2020)
Effect of Multi-Pass Caliber Rolling on Dilute Extruded Mg-Bi-Ca Alloy
Abstract
A Mg-1.32Bi-0.72Ca (BX11) alloy having bimodal grain structure was successfully prepared by a novel processing route of combining extrusion and three-pass caliber rolling. The first extruded and then caliber-rolled (E-CRed) alloy demonstrates a necklace-like grain structure with ultrafine grains formed around the microscale deformed grains, which is remarkably different from the uniform microstructure of the as-extruded alloy. In addition, the E-CRed BX11 alloy exhibits strong basal texture which is mainly original from the microscale deformed grains. Furthermore, the E-CRed BX11 alloy demonstrates excellent comprehensive mechanical properties, with an ultra-high yield strength of 351 MPa and a good elongation to failure of 13.2%. The significant strength improvement can be mainly attributed to the significant grain refinement and much stronger basal texture compared with the as-extruded sample.
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