Microstructure evolution and deformation behavior of ultrafine-grained Al-Zn-Mg alloys with fine η' precipitates
Microstructure evolution and deformation behavior of ultrafine-grained Al-Zn-Mg alloys with fine η' precipitates
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DOI：
10.1016/j.actamat.2010.08.034
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发表时间：
2010-12
期刊：
影响因子：
9.4
通讯作者：
Siyuan Zhang;W. Hu;R. Berghammer;G. Gottstein
中科院分区：
文献类型：
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作者：
Siyuan Zhang;W. Hu;R. Berghammer;G. Gottstein
采用限制通道模压法对具有细小η′相的Al-5 Zn-1.6Mg合金进行了时效处理，使其晶粒细化到≤ 100 nm。通过显微组织观察和力学测试来表征材料在不同程度的严重塑性变形前后的特征。变形处理提高了合金的强度，但限制了其加工硬化性。变形机制的分析表明，塑性进行位错滑移通过超细晶细胞和亚晶排列。η′相通过弥散强化强化合金，但在晶粒细化过程中阻碍了应变速率敏感性的提高。讨论了η′相对合金加工过程中位错组态和变形机制的影响。
An aged Al–5Zn–1.6Mg alloy with fine η′ precipitates was grain refined to ∼100nm grain size by means of confined channel die pressing. Microstructure observations and mechanical tests were carried out to characterize the materials before and after various degrees of severe plastic deformation. Deformation processing enhanced the strength of the alloy, but limited its work hardenability. An analysis of deformation mechanisms revealed that plasticity proceeded by dislocation slip through ultrafine-grained cellular and subgrain arrangements. η′ precipitates strengthened the alloy by dispersion hardening, but retarded an increase in the strain rate sensitivity during grain refinement. The influence of η′ precipitates is discussed with respect to their effect on dislocation configurations and deformation mechanisms during processing of the alloy.