铝合金磨擦搅拌焊接机理及工艺实验研究

【作者】 周鹏展；

【导师】 贺地求；

【作者基本信息】 中南大学 ， 机械设计与理论， 2002， 硕士

【摘要】 摩擦搅拌焊是一种用于低熔点铝合金板材的固态焊接方法，用该方法可以焊接通常熔化焊方法难于焊接的铝合金材料。而目前广泛应用的铝合金的连接大多采用铆接或机械连接的形式，没有发挥出它轻质高强的特性，因此研究铝合金的摩擦搅拌焊接技术具有很重要的工程应用价值。 由于摩擦搅拌焊的应用时间不长，目前对摩擦搅拌焊接头形成机理的研究还处于起步阶段。国内在该技术的工程应用方面还是空白。摩擦搅拌焊接的核心技术在于特殊结构形状的焊头及相匹配的工艺参数，它决定了摩擦搅拌焊接的应用范围。为了开发铝合金的摩擦搅拌焊接技术，本文基于粘着摩擦理论，初步探讨了摩擦搅拌焊接中的焊接机理，建立了摩擦搅拌焊接中的能量转换模型，揭示了摩擦搅拌焊接中焊接温度变化特征及对显微组织的影响，其中峰值温度是重要参数，将它控制在0.8Tm(即大约450℃)左右时，能获得较好的焊缝组织；在此基础上设计了多种特形焊头，并用来对多种铝合金材料进行焊接工艺实验，优选出了尖锥螺旋形焊头及相匹配的工艺参数，分析了焊头形状、旋转速度、焊接速度等对焊缝质量的影响，为进一步研究开发具有自主知识产权的摩擦搅拌焊接技术提供理论和实践依据。更多还原

【Abstract】 The technology of Friction Stir Welding is a new, solid-state welding method. It has enabled us to butt-weld low fusibility alloys, such as aluminum alloys, which are often difficult to fusion weld, without voids, cracking, or distortion. However, the widely applied aluminum alloys is mostly joined in rivet joint or mechanical joint at present. It does not validly utilize the full properties of light mass and high strength in aluminum alloys. So it is very important to study the friction stir welding technology of aluminum alloys.Because the application time is not long, it is in the early stage to study the mechanic of friction stir welding. It is also not applied in our country. The core technology in friction stir welding is the special devised pin and the matched technology parameters, for it controls the application field in friction stir welding. To grasp the friction stir welding technology of aluminum alloys, and based on a sticky friction theory, the welding mechanism in friction stir welding is studied, and an energy model of friction stir welding is established, then the characters of thermal variance in friction stir welding is disclosed, and it is also disclosed that the thermal variant has an effect on the welding microstructure, and the peak temperature is an important parameter, for the reason that a good welding is gained when the peak temperature is kept about 0.8Tm (about 450癈). Finally, based on the above theoretical analysis, several kinds of special pin is designed, and by welding experiments for many kinds of aluminum alloys, some technology parameters for the select sharp-threw pin are obtained, and the influenceof the stirrer’s shape, rotation speed, and welding speed etc on joint quality is studied. It has laid a theoretic and experimental foundation for further research and development for friction stir welding with our intellectual property rights.更多还原