异种金属材料7A04铝-T2紫铜惯性径向摩擦焊接工艺及机理研究

发布时间：2018-04-03 06:49

本文选题：惯性径向摩擦焊　切入点：7A04铝合金　出处：《重庆大学》2015年硕士论文

【摘要】：铝铜金属材料在工业生产中的应用越来越广泛,然而由于两种材料的化学成分、机械性能及熔点的差异,铝-铜异种金属的焊接一直是材料学科中的难点。惯性径向摩擦焊接是利用摩擦产热来实现材料的固相连接技术,对于异种金属材料的焊接有压倒性的优势。因此,本文针对7A04铝棒和T2紫铜环异种金属材料,采用惯性径向摩擦焊接方法探索性的对其可行性进行研究。然而,目前关于铝-铜异种金属材料摩擦焊接的相关研究较少。本文通过实验的方法,对实验所得摩擦焊接头的宏观形貌进行分析,利用光学显微镜和扫描电镜对接头微观组织进行观察,对接头的显微硬度和剪切强度进行测试。分析结果表明:采用惯性径向摩擦焊接方法来焊接7A04铝和T2紫铜异种金属材料是可行的。当最高转速为4100r/min,预摩擦转速和摩擦转速为4000r/min,顶锻转速为2000r/min,顶锻压力和摩擦压力分别为8.0MPa和4.0MPa时,接头质量最稳定且最佳,接头界面产生塑性变形层、动态再结晶、元素扩散互溶,实现了冶金结合。接头焊缝包含3个区域:细晶粒区(Ⅰ区,FGZ)、过渡区(Ⅱ区,TZ)及热影响区(Ⅲ区,HAZ);FGZ和HAZ为圆形颗粒状晶粒,FGZ晶粒尺寸细小,HAZ晶粒粗大,大于母材;TZ晶粒呈细长状,尺寸大小不一,平均晶粒尺寸介于细晶粒区和母材区之间。显微硬度和剪切强度测试结果与宏观和微观分析结果吻合。本文还对摩擦焊中飞边形成机理进行了分析,提出了飞边效应,并分析了工艺参数对接头质量的影响规律。结果发现,飞边形成机理就是在径向力的切向分力与摩擦力的合力作用下,导致材料向合力方向流动,并且合力越大的地方流动速度及材料流动量越大,从而形成飞边。焊接之前必须除去铝材表面的氧化膜,文中以产生飞边的形式将其挤出,飞边多少的表现形式为烧损量的大小,本文中最佳烧损量值范围:3.0-3.5mm之间。顶锻压力和摩擦压力对烧损量大小起着决定性的作用;摩擦压力与烧损量呈正相关关系,即摩擦压力越大,烧损越高;摩擦压力越小,烧损越低。摩擦压力对焊接接头质量有很大影响,在摩擦压力值大于4MPa时,形成的焊接接头质量更良好,不易形成缺陷。
[Abstract]:Aluminum-copper metal materials are widely used in industrial production. However, due to the difference of chemical composition, mechanical properties and melting point of the two materials, the welding of Al-Cu dissimilar metals is always a difficult point in the field of materials.Inertial radial friction welding (IRFW) is a solid phase bonding technology which uses friction heat to realize material bonding. It has an overwhelming advantage for dissimilar metal welding.Therefore, the feasibility of inertial radial friction welding (IRFW) for 7A04 aluminum rod and T2 copper ring dissimilar metal materials is studied in this paper.However, there are few researches on friction welding of aluminum-copper dissimilar metal materials.In this paper, the macroscopic morphology of friction welded joints was analyzed by means of experiments. The microstructure of the joints was observed by optical microscope and scanning electron microscope, and the microhardness and shear strength of the joints were tested.The results show that it is feasible to weld 7A04 aluminum and T2 copper dissimilar metals by inertial radial friction welding.When the maximum rotational speed is 4100r / min, the prefriction speed and friction speed are 4000r / min, the forging speed is 2000rr / min, the forging pressure and friction pressure are 8.0MPa and 4.0MPa, respectively, the quality of the joint is the most stable and the best, the plastic deformation layer is produced at the interface of the joint, and the dynamic recrystallization occurs.The element diffuses and dissolves mutually, realizes the metallurgical union.The average grain size is between the fine grain area and the base metal region.The results of microhardness and shear strength are in agreement with the results of macro and micro analysis.In this paper, the mechanism of flash edge formation in friction welding is analyzed, the flash effect is put forward, and the influence of process parameters on joint quality is analyzed.The results show that the mechanism of flange formation is caused by the combined force of tangential force and friction force of radial force, resulting in the flow of materials towards the direction of resultant force, and the greater the resultant force, the greater the velocity of flow and material flow, thus forming the flying edge.Before welding, the oxide film on the aluminum surface must be removed, and extruded in the form of flash edge in this paper. The form of flash edge is the size of burning loss. The optimum burning loss value in this paper is between 3. 0 and 3. 5 mm.The forging pressure and friction pressure play a decisive role in the burning loss, and the friction pressure has a positive correlation with the loss amount, that is, the higher the friction pressure, the higher the burning loss, and the lower the friction pressure, the lower the burn loss.The friction pressure has a great influence on the quality of welded joints. When the friction pressure is greater than 4MPa, the quality of welded joints is better and the defects are not easy to be formed.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG453.9

【引证文献】