大压下量限宽轧制AZ31镁合金板材的边裂行为及强化机制  

Edge Crack Behavior and Strengthening Mechanism of Width-limited Rolled AZ31 Magnesium Sheet with Large Reduction

作　　者：聂慧慧 郑留伟 田静[2] 梁伟 NIE Huihui;ZHENG Liuwei;TIAN Jing;LIANG Wei(College of Mechanical and Vehicle Engineering,Taiyuan University of Technology,Taiyuan 030024;Shanxi Key Laboratory of Advanced Magnesium-based Materials,Taiyuan 030024;Instrumental Analysis Center,Taiyuan University of Technology,Taiyuan 030024)

机构地区：[1]太原理工大学机械与运载工程学院,太原030024 [2]先进镁基材料山西省重点实验室,太原030024 [3]太原理工大学分析测试中心,太原030024

出　　处：《机械工程学报》2021年第8期146-153,共8页Journal of Mechanical Engineering

基　　金：国家自然科学基金(52005362,U1810208,U1710254);山西省高等学校科技创新(2019L0149,2019L0994)资助项目。

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。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.

关 键 词：AZ31镁合金板 限宽轧制 大压下量 边裂 强化 

分 类 号：TG33[金属学及工艺—金属压力加工]