Size effects on the springback of CuZn37 brass foils in tension and micro W-bending
Size effects on the springback of CuZn37 brass foils in tension and micro W-bending
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DOI：
10.1177/0954405417690557
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发表时间：
2018-12
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影响因子：
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通讯作者：
Xiaoyu Liu;Shiping Zhao;Y. Qin;Chunju Wang;Wan-Adlan Wan-Nawang-Wan-Adlan-Wan-Nawang-1399641537
中科院分区：
文献类型：
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作者：
Xiaoyu Liu;Shiping Zhao;Y. Qin;Chunju Wang;Wan-Adlan Wan-Nawang-Wan-Adlan-Wan-Nawang-1399641537
随着人们对微型化要求的不断提高，对微小型零件成形质量和尺寸精度的要求也越来越高。回弹是影响微弯曲件精度的决定性因素，尺寸效应对回弹的影响很大。为了探索与尺寸效应相关的回弹行为并评价微弯曲件的成形质量，对不同厚度和晶粒尺寸的CuZn37黄铜箔材进行了箔材厚度、晶粒尺寸及其交互作用对回弹行为影响的实验研究。通过微拉伸试验获得的实验结果表明，屈服强度，杨氏模量和伸长率有密切的相关性与厚度平均晶粒尺寸比。使用微W弯曲工艺进行弯曲测试。观察到回弹和负回弹现象。结果表明，尺寸效应对回弹量的影响取决于回弹行为，如正回弹或负回弹。此外，还对回弹行为的离散现象进行了定量分析。当厚度与平均晶粒尺寸之比减小时，观察到50 μ m厚试样的分散性增加，而随着晶粒尺寸的增加，75 μ m和100 μ m厚试样的负回弹分散性减小的趋势相反。最后，对W形微弯曲件的成形质量进行了评定。
With the ever-increasing demands on miniaturization, the requirement on good forming quality and high-dimensional accuracy of micro-parts is dramatically motivated. As a decisive factor affecting the accuracy of micro-bent parts, the springback is significantly influenced by size effects. In order to explore size-effect-associated springback behaviour and evaluate the forming quality of micro-bent parts, an experimentally based investigation on the influence of foil thickness, grain size and their interactive effect on the springback behaviour of CuZn37 brass foils with different thicknesses and grain sizes was carried out. The experimental results obtained via micro-tensile tests revealed that the yield strength, Young’s modulus and elongation had a close correlation with the thickness-to-average-grain-size ratio. A micro W-bending process was used to perform the bending tests. Both springback and negative springback phenomena were observed. It was found that how size effects may influence the amount of springback would depend on the springback behaviours, for example, positive springback or negative springback. In addition, scatter phenomenon of the springback behaviour was analysed quantitatively. An increased scatter was observed for the 50-µm-thick specimens when the thickness to average grain size decreased, whereas an inverse tendency of the decreased scatter of the negative springback was found for the 75- and 100-µm-thick specimens with the increase in the grain size. Finally, forming quality of the W-shaped micro-bent parts was assessed.