Experimental and numerical study on deformation behavior in dieless drawing process of superplastic microtubes
Experimental and numerical study on deformation behavior in dieless drawing process of superplastic microtubes
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DOI：
10.1016/j.jmatprotec.2007.03.084
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发表时间：
2007-08-01
影响因子：
6.3
通讯作者：
Manabe, K.
中科院分区：
文献类型：
--
作者：
Furushima, T.;Manabe, K.
微管通常用于微系统技术（MST）和微机电系统（MEMS）中的微部件，例如微喷嘴、无痛针和微反应器。为了制造微管，超塑性无模拉伸，即，开发了一种利用超塑性特性的无模拉伸工艺。与传统工艺相比，超塑性无模拉伸具有无需模具、芯棒和芯棒等工具，柔性大等优点。此外，该过程具有独特的变形行为，即所谓的“截面几何相似定律”，即直径比d/D在该过程中保持恒定值。本文从实验和数值模拟两个方面研究了其满足截面几何相似律的机理。实验中，超塑性Zn-22%Al和AZ 31镁合金管外径为2 mm，壁厚为0.5圈作为管状工件。采用带空冷喷嘴的高频感应加热装置进行无模拉伸。采用热力耦合有限元法研究了微细管超塑性无模拉伸的变形行为。通过与实验结果的对比，验证了有限元建模的有效性。无模拉伸实验结果表明，该工艺满足截面几何相似律，尺寸最小。有限元分析结果和理论分析结果表明，单轴应力状态和各向同性材料是满足截面几何相似律的重要因素。从这些结果中，阐明了截面几何相似律在该工艺中的作用机理，并证明了该工艺在微管制造中的有效性。(c)2007年由Elsevier B. V.出版。
Microtubes are commonly used and required for micro components in micro system technologies (MST) and micro electro-mechanical systems (MEMS), for example, micro nozzles, painless needles and micro reactors. To fabricate microtubes, superplastic dieless drawing, i.e., dieless drawing process utilizing superplastic characteristics, has been developed. Compared with conventional processes, superplastic dieless drawing has great advantages of not requiring tools such as dies, plugs and mandrels and high flexibility. Furthermore, the process has a unique deformation behavior so called "geometrical similarity law in cross section" that diameter ratio d/D maintains a constant value in the process. In this study, its mechanism for satisfying the geometrical similarity law in cross section is focused on experimentally and numerically. In the experiment, superplastic Zn-22%Al and AZ31 magnesium alloys tubes with an outer diameter of 2 mm, and a wall thickness of 0.5 turn were used as tubular workpieces. A high-frequency induction heating apparatus with an air-cooling nozzle was used for dieless drawing. The deformation behavior of a microtube in superplastic dieless drawing was investigated using finite element method (FEM) with coupled thermo-mechanical analysis. The validity of FE modeling was verified by a comparison with the experimental results. The experimental dieless drawing results imply that the geometrical similarity law in cross section with the minimization of dimensions is satisfied by this process. Furthermore, it was clarified from the FEM results and analytical results that uniaxial stress state and isotropic material are essential factors for satisfying the geometrical similarity law in cross section in the process. From these results, the mechanism of the geometrical similarity law in cross section in this process was clarified, and the effectiveness of this process was demonstrated for microtube fabrication. (c) 2007 Published by Elsevier B.V.