Mechanical anisotropy and deep drawing behaviors of AZ31 magnesium alloy sheets produced by unidirectional and cross rolling
Mechanical anisotropy and deep drawing behaviors of AZ31 magnesium alloy sheets produced by unidirectional and cross rolling
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DOI：
10.1016/j.jmatprotec.2014.08.020
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发表时间：
2015
影响因子：
6.3
通讯作者：
Weiqin Tang;Shiyao Huang;Dayong Li;Ying-hong Peng
中科院分区：
文献类型：
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作者：
Weiqin Tang;Shiyao Huang;Dayong Li;Ying-hong Peng
AZ31 镁片是通过两种轧制技术在挤压板材上轧制而成：交叉轧制 (CR)，一种实验室工艺，其中每次轧制道次后轧制方向改变 90°，以及传统的单向轧制 (UR)，其中轧制方向不变。在室温下研究了 UR 和 CR 板材的微观结构和织构、强度和伸长率方面的拉伸机械性能以及各向异性。正如预期的那样，UR片材由于强基底型织构而具有明显的平面各向异性；然而，CR 板材显示出 28% 断裂伸长率的改善延展性和接近 1 的低 r 值，从而增强了拉拔能力。在 150° C 下进行的深拉试验表明，UR 杯表现出明显的耳部，这与平面各向异性 Δr 为大负值相对应，而 CR 杯的耳部由于 Δr 为正值而可以忽略不计。此外，由于与 UR 板材相比，CR 板材具有较低的法向各向异性 r 值和较大的伸长率，因此可产生比 UR 板材更深的拉深杯。
Magnesium AZ31 sheets were produced by rolling on the as-extruded plates with two rolling techniques: cross rolling (CR), a laboratory process wherein the rolling direction is changed by 90° after each rolling pass, and conventional unidirectional rolling (UR) wherein the rolling direction is unchanged. The microstructure and texture, tensile mechanical properties in terms of strength and elongation, and also the anisotropy of the UR and CR sheets were investigated at room temperature. As expected, the UR sheet has obvious planar anisotropy from the strong basal-type texture; however, the CR sheet shows improved ductility of 28% elongation-to-fracture and low r value close to 1 which enhances drawing capability. Deep drawing tests carried out at 150° C reveals that the UR cups show obvious earing corresponding to a large negative value of planar anisotropy Δr, while earing of the CR cups is negligible due to a positive value of Δr. Moreover, the CR sheet produces a deeper drawn cup than the UR sheet as a result of its lower normal anisotropy r¯ value and larger elongation compared with the UR sheet.