大压下量限宽轧制AZ31镁合金板材的边裂行为及强化机制

doi:10.3901/JME.2021.08.146

摘要/Abstract

摘要： AZ31镁合金板在航空、航天、汽车、电子、武器等轻量化领域具有广阔的应用前景，但其塑性成形能力较差，无法承受单道次大压下量轧制变形，且易产生边裂。对AZ31镁合金板分别进行传统轧制和限宽轧制，结果表明，采用限宽轧制时，镁合金板材的单道次实际压下量最高可达50%，双向压缩应力状态可有效抑制边裂产生，裂纹长度在2 mm以内；同等压下量时，传统轧制的镁合金板边裂严重，中心区域也出现鱼鳞状裂纹。与原始板材相比，限宽轧制镁合金板的位错强化作用明显，沿轧向的屈服强度和抗拉强度分别提高了54.7%和54.1%，沿横向的屈服强度和抗拉强度分别提高了383.9%和131.1%。限宽轧制板材沿横向的强度和伸长率均高于轧向，主要原因是沿横向的细晶强化作用更强。

关键词: AZ31镁合金板, 限宽轧制, 大压下量, 边裂, 强化

Abstract: AZ31 magnesium alloy sheet has a broad application prospect in the field of lightweight including aviation, aerospace, automotive, electronics, weapons, etc. However, its plastic forming ability is so poor that it cannot withstand large rolling reduction in a single pass and easy to produce edge cracks. Traditional rolling and width-limited rolling are conducted on AZ31 sheet respectively. The results show that the actual maximum single rolling reduction can reach 50% and the length of edge crack is less than 2 mm under bidirectional compressive stress. However, serious edge cracks and fish-scale cracks in center region can be observed in AZ31 sheet fabricated by traditional rolling with 50% rolling reduction. Compared with as-received sheet, the strengthening mechanism of the width-limited rolled magnesium sheet is mainly dislocation strengthening. The yield strength and tensile strength of width-limited rolled sheet along the rolling direction increase by 54.7% and 54.1%, and along the transverse direction increase by 383.9% and 131.1%, respectively. The strength and elongation along the transverse direction of width-limited rolled sheet are higher than that along the rolling direction owing to its stronger refinement strengthening effect.

Key words: AZ31 magnesium alloy sheet, width-limited rolling, large rolling reduction, edge crack, strengthening

中图分类号:

TG33

聂慧慧, 郑留伟, 田静, 梁伟. 大压下量限宽轧制AZ31镁合金板材的边裂行为及强化机制[J]. 机械工程学报, 2021, 57(8): 146-153.

NIE Huihui, ZHENG Liuwei, TIAN Jing, LIANG Wei. Edge Crack Behavior and Strengthening Mechanism of Width-limited Rolled AZ31 Magnesium Sheet with Large Reduction[J]. Journal of Mechanical Engineering, 2021, 57(8): 146-153.

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