为揭示双峰分离非基面织构AZ31镁合金板材预变形后的室温变形行为及微观组织演化规律，对该板材施加压下量5%的深冷轧制预变形，结合室温单轴拉伸和微观组织表征实验，研究预变形对制备板材力学行为及微观组织演变的影响。结果表明，沿轧制方向(RD)试样的初始屈服强度和断裂延伸率较未预变形试样分别提升212.5%和降低56.9%。沿板材横向(TD)试样的初始屈服强度和断裂延伸率较未预变形试样分别降低6.7%和提升37.9%。不同方向试样初始屈服强度的差异主要是由于TD试样中TD织构组分所对应的晶粒比RD试样中双峰分离非基面织构组分所对应的晶粒更容易激活基面<a>滑移。断裂延伸率的差异主要是由于在RD试样中，{10\overline{\mathrm{1}}2}拉伸孪晶的扩张受到抑制，会较早出现{10\overline{\mathrm{1}}1}压缩孪晶，而在TD试样中，{10\overline{\mathrm{1}}2}拉伸孪晶可以有效扩张，且后期出现一定数量的{10\overline{\mathrm{1}}1}-{10\overline{\mathrm{1}}2}双孪晶来承载/协调塑性应变。

An AZ31 Mg alloy sheet with bimodal non-basal texture exhibits good formability at room temperature. However, its initial yield stress (YS) is relatively low during uniaxial tension along the rolling direction (RD) at room temperature, which limits its potential for further application. Recent studies have demonstrated that introducing {10\overline{\mathrm{1}}2} extension twin (ET) through predeformation can improve the mechanical properties of Mg alloy sheets with a basal texture at room temperature. However, the predeformation process for Mg alloy sheets with non-basal texture has rarely been investigated, along with their subsequent plastic deformation behavior at room temperature. Therefore, to investigate the room temperature deformation behavior and microstructure evolution of an AZ31 Mg alloy sheet with bimodal non-basal texture after predeformation, this work exerted a 5% thickness reduction on the sheet via cryogenic rolling. Then uniaxial tension experiments at room temperature and microstructure characterization experiments were conducted to illuminate the effect of predeformation on the mechanical behavior and microstructure evolution of the fabricated sheet. The findings indicate that when loaded along the RD, the YS and fracture elongation (FE) of the predeformed sample are 212.5% larger and 56.9% smaller than those of the non-predeformed sample. When loaded along the transverse direction (TD), the YS and FE of the predeformed sample are 6.7% smaller and 37.9% larger than those of the non-predeformed sample. The difference in YS in the predeformed samples is primarily attributed to easier activation of basal <a> slip in grains with a TD texture component in the TD sample than in grains with a bimodal non-basal texture component in the RD sample. The difference in FE in the predeformed samples is due to the inhibition of the expansion of preexsiting {10\overline{\mathrm{1}}2} ETs in the RD sample, resulting in the early occurrence of {10\overline{\mathrm{1}}1} compression twins (CTs). In comparison, the expansion of preexsiting {10\overline{\mathrm{1}}2} ETs can be effectively performed in the TD sample. Additionally, some {10\overline{\mathrm{1}}1}-{10\overline{\mathrm{1}}2} double twins (DTs) would be activated at the later stage of tensile deformation to sustain and/or accommodate local plastic strain.