S.B. Zhang and H. Nejishi (Department of Mechanical Engineering and Intelligent Systems
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University of E feetro- Communications
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Chofugaoka 1-5-1
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Chofu-shi
,
Tokyo 182-8585
,
Japan)
金属学报(英文版)
In this paper local compressive deforming of a hexagonal tube of aluminum (JISA1050) is investigated by an electromagnetic forming. The hexagonal tubes are annealed for 1h. at 400℃, which have 55mm width with 1mm thickness, and 10mm corner edius. The deformed ation of the hexagonal tube, i.e., bead width, is 10, 15, 20mm, respectively. The magnetic flux density in the gap between the field shaper and the external surface of hexagonal tube is measured, and the result is that the magnetic flux density for a given voltage is almost identical along the gap) and decreases with increasing the gap. The profiles and the strain distribution of the hexagonal tube de- formed are affected by the change Of the charging voltage and the dimensions of a bead width. The greater compressive strum in the cireuwtrential direction is develOPed on plane part near corner,while tensile strain on the corner occurs. A metallic block is inserted inside the hexagonal tube so that uniform profile can be obtained. The simulation of the forming is performed by a finite-element method and compared with the experimental results.
关键词:
electromagnetic forming
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null
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null
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null
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null
刘大海
,
于海平
,
李春峰
金属学报
doi:10.3724/SP.J.1037.2011.00741
为揭示磁脉冲成形的增塑机制, 采用理论分析与微观组织观察相结合的方法对5052铝合金板材磁脉冲动态拉伸过程中动态成形行为和塑性失稳机制进行了系统研究. 结果表明, 惯性力在动态成形中起主要作用,惯性力对试样的结构失稳具有抑制作用, 从而使试样的塑性提高并产生分散失稳;5052铝合金动态成形和准静态成形的成形性质相似, 不会产生特殊的组织结构,塑性变形机制均为位错滑移机制; 准静态成形过程以均匀单系位错滑移为主,断裂伴随着位错的缠结和攀移; 而动态成形过程中, 位错滑移趋于多系开动,在大面积区域出现明显的交滑移现象, 且滑移带较准静态成形时窄且密,位错组态更均匀; 动态成形的多系滑移和位错均化作用可在比准静态成形高的多的塑性应变水平下形成, 从而使材料表现出较高的塑性和强度.
关键词:
铝合金
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electromagnetic forming
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plastic instability
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uniaxial tension
