Abstract

High strain-rate rolling (≥ 10 s⁻¹) has been successfully employed to produce AZ31 magnesium alloy sheets to a high reduction of 82% with a fine grain structure in a single pass. The rolled sheets inevitably undertake various forming processes such as press and deep forming in the fabrication stage. To investigate the formability, the Erichsen tests were carried out on high strain rate rolled AZ31 magnesium alloy sheets at room temperature. The relationship among mechanical properties, microstructure and formability were investigated. The crack behavior during Erichsen tests was also studied. It was found that the formability was related to the lowest in-plane tensile strengthen and dislocation density of initial microstructure. The competitive relationship between micro-crack and twinning/shear bands would also influence the formability of high strain rate rolled magnesium alloy sheets. Deformed shear band with substaintial twins prohibits the crack extension and enhances strengthen of materials in front of crack tip.

Graphic Abstract

中文翻译：

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高应变率轧制AZ31镁合金薄板的显微组织和力学性能对成形性的影响

摘要

高应变率轧制（≥ 10 s ^-1) 已成功地用于生产 AZ31 镁合金板，单道次可将 AZ31 镁合金板降低 82%，并具有细晶粒结构。轧制的板材在制造阶段不可避免地要进行压制、深成形等各种成形工艺。为了研究可成形性，在室温下对高应变率轧制 AZ31 镁合金板进行 Erichsen 试验。研究了力学性能、显微组织和成形性之间的关系。还研究了 Erichsen 测试期间的裂纹行为。结果表明，成形性与初始显微组织的最低面内拉伸强度和位错密度有关。微裂纹和孪生/剪切带之间的竞争关系也会影响高应变率轧制镁合金板的成形性。具有实质孪晶的变形剪切带阻止裂纹扩展并增强裂纹尖端前材料的强度。

图形摘要