电脉冲辅助AZ31B镁合金板材弯曲成形试验研究

发布时间：2018-05-04 01:34

本文选题：镁合金板材 + 脉冲电流　；参考：《山东大学》2017年硕士论文

【摘要】：镁及镁合金因具有良好的性能被广泛应用于航天、航空、汽车、电子、通讯等领域。但镁合金因密排六方的晶体结构使得镁合金在常温下塑性成形能力较差,限制了镁合金在工业领域中的应用,成为制约镁合金在工业发展中的主要因素。电脉冲辅助镁合金成形作为一种新型的成形工艺,得到广泛关注。作为高能量场在塑性加工中的应用,电脉冲辅助成形在提高镁合金的成形能力的同时能够提高镁合金成形件的表面质量,研究发现,高能脉冲电流对镁合金塑性成形能力的影响,主要是电致塑性效应中的焦耳热效应和纯电致塑性效应的联合作用。本文将高能脉冲电流引入镁合金板材的弯曲成形过程,研究脉冲电流作用下镁合金板材的弯曲成形性能,同时研究电致塑性效应在镁合金板材弯曲成形过程中的作用,探讨电致塑性效应影响镁合金成形性能的作用机理。本文的主要研究内容如下:(1)自主设计了电脉冲辅助镁合金板材弯曲成形模具,包括有约束V形弯曲模具、V形自由弯曲模具、U形弯曲模具,为后续电脉冲辅助弯曲试验的开展提供了便利。(2)基于电脉冲辅助镁合金板材V/U形弯曲试验,通过单因素试验、响应曲面法和正交试验法研究了不同工艺参数对镁合金板材V/U形弯曲成形性能的影响,获得了不同电脉冲参数下镁合金板材的成形力以及成形角度的变化规律。(3)通过电流流向的控制,研究了脉冲电流方向对镁合金板材弯曲性能的影响;开展了镁合金板材传统热成形弯曲试验,通过两种成形条件下试件的宏观弯曲性能及微观组织变化的对比分析,研究了弯曲成形工艺中脉冲电流对镁合金板材微观组织的影响,探讨了电致塑性效应作用机理。
[Abstract]:Magnesium and magnesium alloys are widely used in aerospace, aviation, automobile, electronics, communication and other fields because of their good properties. However, due to the hexagonal crystal structure, the plastic forming ability of magnesium alloy is poor at room temperature, which limits the application of magnesium alloy in industrial field and becomes the main factor restricting the development of magnesium alloy in industry. As a new forming process, electric pulse assisted magnesium alloy forming has been paid more and more attention. As the application of high energy field in plastic processing, electric pulse assisted forming can improve the forming ability of magnesium alloy and improve the surface quality of magnesium alloy forming parts. The effect of high energy pulse current on the plastic forming ability of magnesium alloy is mainly due to the combined effect of Joule heat effect and pure electro-plastic effect. In this paper, the high energy pulse current is introduced into the bending forming process of magnesium alloy sheet, and the bending forming property of magnesium alloy sheet under pulse current is studied. At the same time, the effect of electroplastic effect on the bending forming process of magnesium alloy sheet is studied. The mechanism of the effect of electroplastic effect on the formability of magnesium alloy was discussed. The main research contents of this paper are as follows: (1) the electric pulse assisted bending die for magnesium alloy sheet is designed independently, including the constrained V-shaped bending die, the V-shaped free bending die and the U-shaped bending die. This paper provides convenience for the further development of electric pulse assisted bending test. Based on the electric pulse assisted V / U bending test of magnesium alloy sheet, the single factor test is adopted. The effect of different process parameters on V / U bending properties of magnesium alloy sheet was studied by response surface method and orthogonal test. The influence of the direction of pulse current on the bending properties of magnesium alloy sheet was studied by controlling the current flow through the control of the forming force and forming angle of magnesium alloy sheet under different electrical pulse parameters. The traditional hot forming bending test of magnesium alloy sheet was carried out. The effect of pulse current on microstructure of magnesium alloy sheet was studied by comparing and analyzing the macroscopic bending properties and microstructure changes of the specimens under two forming conditions. The mechanism of electroplastic effect is discussed.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG306;TG661

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