Influence of the precipitate-free zone width on the tensile properties of an Al-6 Wt pct Zn-1.2 Wt pct Mg alloy
Influence of the precipitate-free zone width on the tensile properties of an Al-6 Wt pct Zn-1.2 Wt pct Mg alloy
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DOI：
10.1007/bf02668000
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发表时间：
1973-06
期刊：
影响因子：
--
通讯作者：
M. Abe;K. Asano;A. Fujiwara
中科院分区：
文献类型：
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作者：
M. Abe;K. Asano;A. Fujiwara
研究了不同无析出带宽度的Al-6wt%Zn-1.2wt%Mg合金的力学性能。无沉淀区（PFZ）的宽度已被改变的淬火中断技术没有任何明显的变化，在沉淀物的大小和分布。在PFZ的宽度和猝灭中断时间之间观察到一个重要的关系;即，PFZ的宽度与在200°C下的保持时间的平方根成比例地增加。通过对应力-应变曲线的分析以及对微变形试样中位错排列的观察，发现塑性变形优先发生在PFZ中。在变形的初始阶段，PFZ宽度的变化影响很大，但在后期，加工硬化率似乎是几乎无关的PFZ宽度。拉伸试验表明，极限抗拉强度和0.2%的屈服应力的PFZ的宽度的增加下降很小，而均匀延伸率几乎是恒定的，无论在不均匀延伸率的减少。在变形的初始阶段的加工硬化率被发现成比例地减少PFZ宽度的倒数。这种关系可以从加工硬化的位错模型来解释。
The mechanical properties of an Al-6 wt pct Zn-1.2 wt pct Mg alloy with various width of precipitate-free zones have been investigated. The width of the precipitate-free zone (PFZ) has been changed by the quench interruption technique without any appreciable change in the size and distribution of precipitates. An important relationship has been observed between the width of the PFZ and the quench-interruption period;i.e., the width of the PFZ increases in proportion to the square root of the holding time at 200°C. From the analysis of stress-strain curves as well as the observation of dislocation arrangements in slightly deformed specimens, the plastic deformation has been found to occur preferentially in the PFZ. The initial stage of deformation is much affected by the change in the width of the PFZ, but in the later stage, the work-hardening rate seems to be almost independent of the PFZ width. Tensile tests show that the ultimate tensile strength and the 0.2 pct proof stress decrease very little with increasing width of the PFZ, while the uniform elongation is practically constant regardless of the reduction in the nonuniform elongation. The work-hardening rate at the initial stage of deformation is found to decrease in proportion to the reciprocal of the PFZ width. This relationship can be explained from the dislocation model for work hardening.