AZ31镁合金等径角变形与断裂行为研究
Deformation and fracture during equal channel angular pressing of AZ31 magnesium alloy
康锋
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作者单位：晋西车轴股份公司
中文关键字：等径角变形；AZ31镁合金；剪切断裂；局部流变
英文关键字：Equal channel angular pressing; AZ31 magnesium alloy; shear fracture; flow localization
中文摘要：本文研究了AZ31镁合金在温度150℃～250 ℃、等效应变速率0.001～0.25s-1范围内一道次等温等径角变形（ECAP）过程中的变形与断裂行为。实验结果表明，AZ31镁合金在ECAP变形过程中极易发生局部剪切，而均匀变形只发生在高温和低应变率条件下。剪切带和剪切断裂的观察结果可以由量化应力集中趋势的局部流变集中参数 来预测。通过材料性能对局部流变趋势的影响，可以选择最优的加工方案，以获得材料的均匀变形。
英文摘要：The deformation and fracture characteristics of AZ31 magnesium alloy during equal channel angular pressing (ECAP) were investigated at temperatures between 150 and 250 ℃ and ram speeds producing average effective strain rates between 0.001 and 0.25s-1. The results show that AZ31 magnesium alloy was particularly susceptible to shear localization during ECAP, uniform flow occurred only at high temperatures and low strain rates. Observations of shear banding and shear fracture were interpreted in terms of the tendency for strain concentration as quantified by the flow localization ‘ ’ parameter, or the ratio of the normalized flow softening rate to the strain-rate sensitivity. These understandings of the effect of material properties on flow localization tendency are helpful for the selection of processing parameters with uniform flow during ECAP.