It is widely recognized that rolling Mg alloys is difficult due to their poor ductility. Conventional rolling of Mg alloys often needs to be conducted at high temperatures with multi-pass small thickness reduction, and the strong basal texture often leads to poor ductility and plate cracking. Herein, we conducted a single-pass high-reduction rolling (SPHRR) on AZ91 alloy after pre-homogenization (PH) and RD-ECAP pre-processing (PH + ECAP). Results shows that the AZ91 rolled plate processed by SPHRR (PH + ECAP + R) exhibits a good combination of high tensile strength (ultimate strength of ~420 MPa, yield strength of ~335 MPa) and high ductility (elongation-to-failure of ~19%), together with significantly reduced edge cracks. Microstructure examinations revealed that the improved mechanical property is mainly attributed to a typical bimodal grain structure featured with relatively high Schmidt factors of basal slips (SF_basal). The fine-grain structure produced by the high-pass RD-ECAP pre-processing contributes to the improvement of formability, provides favourable conditions for dynamic recrystallization (DRX) in further rolling and also promotes the formation of the bimodal structure. Overall, the high-pass RD-ECAP is applicable to improve plastic formability of hard-to-deform materials like Mg alloys, and thus has a promising prospect for industrial applications.

众所周知，由于延展性差，轧制镁合金很困难。镁合金的常规轧制通常需要在高温下进行，多次减小厚度并减小厚度，而坚固的基体组织常常导致延展性差和钢板开裂。本文中，我们在预均质化（PH）和RD-ECAP预处理（PH + ECAP）之后，对AZ91合金进行了一次单道次高压缩轧制（SPHRR）。结果表明，经SPHRR（PH + ECAP + R）处理的AZ91轧制板具有高拉伸强度（最终强度约为420 MPa，屈服强度约为335 MPa）和高延展性（断裂伸长率）的良好组合。 〜19％），以及明显减少的边缘裂纹。_基础）。通过高通RD-ECAP预处理产生的细晶粒结构有助于提高可成形性，为进一步轧制中的动态重结晶（DRX）提供了有利条件，并且还促进了双峰结构的形成。总体而言，高通RD-ECAP适用于提高难变形材料（如Mg合金）的塑性成形性，因此在工业应用中具有广阔的前景。