金属薄板超声拉伸及微胀形中超声气膜效应的研究
发布时间：2018-08-22 13:42
【摘要】：金属薄板微成形工艺以其成形工艺简单、成本低、高效、节能等一系列优点而在制造领域内受到广泛的关注。为探究金属薄板在成形过程中的力学性能,国内外很多学者对其进行了相关研究。在超声拉伸方面,本文探究了T2紫铜薄板在超声振动下的力学性能参数;在金属薄板微冲压成形方面,本课题组提出了瞬态粘性介质金属薄板超声微成形方法,通过金属薄板超声微胀形实验,研究了该成形工艺中,超声头主压力、超声振幅及超声加载时间对超声气膜效应中气膜厚度的影响。这些对金属薄板微成形理论的进一步研究具有重要的意义。本论文的主要研究工作及相关结论如下:(1)探究了T2紫铜薄板在不同退火温度下的厚度/晶粒尺寸比关系。实验结果表明:当紫铜薄板的厚度减小到一定程度时,晶粒尺寸受薄板厚度变化的影响较大。在相同热处理温度下,随着紫铜薄板厚度的增加,试样晶粒尺寸也随着增加,厚度/晶粒尺寸比也随着增加;对于同一厚度紫铜薄板而言,随着热处理温度的增加,晶粒尺寸也随着增加,厚度/晶粒尺寸比随着温度的增加而减小,当热处理温度达到600℃以后,厚度/晶粒尺寸比减小的趋势逐渐趋于平缓。(2)研究了T2紫铜薄板在超声拉伸条件下的相关力学性能参数。研究结果表明,当厚度/晶粒尺寸比小于1时,随着厚度/晶粒尺寸比的减小,屈服强度的增幅逐渐增加;变形抗力也随着厚度/晶粒尺寸比的减小而降低。在超声作用下,与未进行退火处理的紫铜薄板相比,经退火处理后的T2紫铜薄板,其屈服强度、抗拉强度及延伸率均出现了不同程度的降低,即表现出明显的“软化效应”。(3)在瞬态粘性介质金属薄板超声微成形工艺中,超声头主压力对气膜的影响呈负相关性,即随着超声头主压力的增加,气膜的厚度呈降低趋势。超声振幅对气膜厚度的影响呈现出先减后增的规律。随着超声加载时间的增加,气膜厚度呈振荡递减的趋势。对于厚度/晶粒尺寸比为1.1的T2紫铜薄板(厚度为30μm,热处理温度为600℃),对其进行微胀形实验,当超声头主压力为3.8MPa、超声振幅为36.54μm、超声加载时间为1.2s时,能够将气膜的厚度控制在0.8-2.2μm之间。
[Abstract]:Metal sheet microforming process has attracted wide attention in manufacturing field because of its simple forming process, low cost, high efficiency, energy saving and so on. In order to study the mechanical properties of sheet metal in forming process, many scholars at home and abroad have studied it. In the aspect of ultrasonic drawing, the mechanical properties of T2 copper sheet under ultrasonic vibration are studied, and the ultrasonic microforming method of transient viscous medium metal sheet is proposed in this paper. The effects of the main pressure of ultrasonic head, ultrasonic amplitude and ultrasonic loading time on the film thickness in ultrasonic film effect were studied by ultrasonic microbulging test of metal sheet. These are of great significance to the further study of metal sheet microforming theory. The main research work and related conclusions are as follows: (1) the relationship between thickness and grain size ratio of T2 red copper sheet at different annealing temperatures has been investigated. The experimental results show that when the thickness of copper sheet decreases to a certain extent, the grain size is greatly affected by the thickness of the plate. At the same heat treatment temperature, with the increase of the thickness of the copper sheet, the grain size of the sample also increases, and the thickness / grain size ratio increases with the increase of the heat treatment temperature. With the increase of grain size, the thickness / grain size ratio decreases with the increase of temperature, and when the heat treatment temperature reaches 600 鈩，
本文编号：2197272
[Abstract]:Metal sheet microforming process has attracted wide attention in manufacturing field because of its simple forming process, low cost, high efficiency, energy saving and so on. In order to study the mechanical properties of sheet metal in forming process, many scholars at home and abroad have studied it. In the aspect of ultrasonic drawing, the mechanical properties of T2 copper sheet under ultrasonic vibration are studied, and the ultrasonic microforming method of transient viscous medium metal sheet is proposed in this paper. The effects of the main pressure of ultrasonic head, ultrasonic amplitude and ultrasonic loading time on the film thickness in ultrasonic film effect were studied by ultrasonic microbulging test of metal sheet. These are of great significance to the further study of metal sheet microforming theory. The main research work and related conclusions are as follows: (1) the relationship between thickness and grain size ratio of T2 red copper sheet at different annealing temperatures has been investigated. The experimental results show that when the thickness of copper sheet decreases to a certain extent, the grain size is greatly affected by the thickness of the plate. At the same heat treatment temperature, with the increase of the thickness of the copper sheet, the grain size of the sample also increases, and the thickness / grain size ratio increases with the increase of the heat treatment temperature. With the increase of grain size, the thickness / grain size ratio decreases with the increase of temperature, and when the heat treatment temperature reaches 600 鈩，
本文编号：2197272
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