Relationship between tensile and shear strengths of the mushy zone in solidifying aluminum alloys
Relationship between tensile and shear strengths of the mushy zone in solidifying aluminum alloys
复制标题
铝合金凝固过程中糊状区拉伸强度与剪切强度的关系
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
T. Sumitomo
中科院分区：
文献类型：
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作者：
A. Dahle;S. Instone;T. Sumitomo
本文用水平拉伸和直剪试验两种不同的方法测定了三种铝合金（Al-4wt%Cu，Al-7wt%Si-1wt%Cu和Al-7wt%Si-4wt%Cu）凝固过程中糊状区的强度发展。从这两种方法的强度结果相互对应的程度比文献中提出的结果更高。拉伸强度开始发展的最大包装固体分数，证实了剪切强度测量。最大堆积分数表示糊状区的内部网络结构建立的点，并且网络的韧带必须断裂以重新排列枝晶。数据表明，在高固体分数的剪切和拉伸强度的收敛趋势，因此，表明变形机制也变得相似。本文提出的结果表明，有可能在整个固相分数范围内建立糊状区力学性能的本构方程，即，从凝聚到完全固化。这些方程可用于预测应力发展和缺陷的形成。
Strength development in the mushy zone during solidification of three aluminum alloys (Al-4 wt pct Cu, Al-7 wt pct Si-1 wt pct Cu, and Al-7 wt pct Si-4 wt pct Cu) has been measured with two different techniques—horizontal tensile testing and direct shear cell testing. The strength results from the two methods correspond with one another to a much higher degree than suggested by the results presented in the literature. Tensile strength starts to develop at the maximum packing solid fraction, confirmed by the shear strength measurements. The maximum packing fraction represents the point where the internal network structure of the mushy zone is established and ligaments of the network must be broken to rearrange the dendrites. The data indicate a converging trend of the shear and tensile strength at high solid fractions, therefore indicating that the deformation mechanisms are also becoming similar. The results presented in this article suggest that it is possible to develop constitutive equations for the mechanical properties of the mushy zone over the entire solid fraction regime, i.e., from coherency to complete solidification. These equations could be used for the prediction of stress development as well as defect formation.