铜与石墨超声波辅助活性钎焊连接方法研究
发布时间：2019-05-14 13:48
【摘要】：目前金属与石墨的连接广泛应用于电器行业中,电器设备的核心部件换向器中更需要实现铜与石墨的连接。石墨与铜的连接通常是在真空或者惰性气体的保护环境下进行,但受炉体尺寸大小的限制,很难在工业上实现批量生产。随着超声波辅助钎焊技术的出现,使铜与石墨在大气环境下的连接成为可能。本文采用了超声波辅助活性钎焊技术,选用并研制了两种活性钎料:高温的Ag-Cu-Zn-Ti钎料和低温的Sn-Ag-Cu-Ti钎料。分析了超声波在钎焊过程中的作用,研究了钎焊工艺及钎焊工艺参数对接头力学性能的影响,并对连接机理进行了探讨。研究结果表明:采用Ag-Cu-Zn-Ti钎料,超声波辅助活性钎焊技术可以实现大气条件下铜与石墨的连接。钎焊温度是接头质量的重要影响因素,在较高的温度下施焊时,金属母材和活性钎料均氧化严重,增加了除去氧化膜的难度,使钎焊困难。对施加2 s超声波作用得到的钎焊接头进行微观组织分析,发现钎缝内部靠石墨侧存在大量破碎的氧化膜,随着超声波作用时间的延长,钎缝内部的氧化膜逐渐减少,当超声波作用10 s时,钎缝中的氧化膜完全消失,形成了较好的接头。钎焊接头的组织组成从铜侧依次为铜/铜锌合金/银基固溶体+铜基固溶体/Ti C反应层/石墨,钎料与石墨侧的连接主要是反应润湿连接。增加超声作用时间与提高钎焊温度会促使界面反应层Ti C的生长,但其不能持续增加。研究还发现,超声波的施加时间影响着钎焊接头的剪切性能,施加超声波不超过10 s时,超声波有提高接头强度的作用,如果超声波作用再持续施加,反而会使接头剪切强度下降。最佳的工艺条件为钎焊温度820℃、超声波作用时间10 s、保温10 min,在此钎焊条件下,钎焊接头强度达到最大值18 MPa采用Sn-Ag-Cu-Ti活性钎料,在大气条件下也能借助超声波辅助实现铜与石墨的连接。在超声波作用2 s至20 s的过程中,在钎缝内部均没有发现有氧化膜的存在。对钎焊接头进行分析时并未发现钎料与石墨发生冶金结合。超声波作用20 s时,在石墨侧没有Ti C反应层的形成,钎料与石墨的连接主要是在超声波的驱动作用下,钎料向石墨内部孔洞中的流动,冷却至室温形成的机械连接。钎焊接头的界面组织从铜侧依次为Cu/Cu3Sn金属间化合物层/Cu6Sn5金属间化合物/Sn-Ti合金、Sn-Ag合金与少量Cu-Ti合金/石墨。当钎焊温度为450℃,施加12s的超声波作用时,得到的接头强度最大,为16 MPa。采用这种低温活性钎料钎焊铜与石墨得到的钎焊接头,剪切强度大于母材石墨本身。
[Abstract]:At present, the connection between metal and graphite is widely used in the electrical industry, and the connection between copper and graphite is more necessary in the commutator, which is the core component of electrical equipment. The connection between graphite and copper is usually carried out in vacuum or noble gas protection environment, but due to the size of furnace body, it is difficult to realize mass production in industry. With the emergence of ultrasonic assisted brazing technology, the connection between copper and graphite in atmospheric environment is possible. In this paper, two kinds of active solder, high temperature Ag-Cu-Zn-Ti solder and low temperature Sn-Ag-Cu-Ti solder, have been selected and developed by using ultrasonic assisted active brazing technology. The function of ultrasonic wave in brazing process is analyzed, the influence of brazing process and brazing process parameters on the mechanical properties of the joint is studied, and the bonding mechanism is discussed. The results show that the connection between copper and graphite can be realized by using Ag-Cu-Zn-Ti solder and ultrasonic assisted active brazing technology. Brazing temperature is an important factor affecting the quality of joints. When welding at higher temperatures, both the base metal and the active solder are oxidized seriously, which makes it difficult to remove the oxide film and make brazing difficult. The microstructure of the brazed joint subjected to 2 s ultrasonic action is analyzed. It is found that there are a large number of broken oxide films on the graphite side of the brazing seam. With the prolongation of ultrasonic action time, the oxide film in the brazing joint decreases gradually. When the ultrasonic wave is applied for 10 s, the oxide film in the brazing seam disappears completely and a good joint is formed. The microstructure composition of brazing joint is copper / copper-zinc alloy / silver-based solid solution copper-based solid solution / Ti C reaction layer / graphite from copper side, and the connection between solder and graphite side is mainly reactive wetting connection. Increasing ultrasonic action time and brazing temperature will promote the growth of interface reaction layer Ti C, but it can not increase continuously. It is also found that the shear properties of brazed joints are affected by the application time of ultrasonic wave. When the ultrasonic wave is applied less than 10 s, the ultrasonic wave can improve the strength of the joint, and if the ultrasonic action continues to be applied, On the contrary, the shear strength of the joint will be reduced. The optimum technological conditions are as follows: brazing temperature 820 鈩，
本文编号：2476766
[Abstract]:At present, the connection between metal and graphite is widely used in the electrical industry, and the connection between copper and graphite is more necessary in the commutator, which is the core component of electrical equipment. The connection between graphite and copper is usually carried out in vacuum or noble gas protection environment, but due to the size of furnace body, it is difficult to realize mass production in industry. With the emergence of ultrasonic assisted brazing technology, the connection between copper and graphite in atmospheric environment is possible. In this paper, two kinds of active solder, high temperature Ag-Cu-Zn-Ti solder and low temperature Sn-Ag-Cu-Ti solder, have been selected and developed by using ultrasonic assisted active brazing technology. The function of ultrasonic wave in brazing process is analyzed, the influence of brazing process and brazing process parameters on the mechanical properties of the joint is studied, and the bonding mechanism is discussed. The results show that the connection between copper and graphite can be realized by using Ag-Cu-Zn-Ti solder and ultrasonic assisted active brazing technology. Brazing temperature is an important factor affecting the quality of joints. When welding at higher temperatures, both the base metal and the active solder are oxidized seriously, which makes it difficult to remove the oxide film and make brazing difficult. The microstructure of the brazed joint subjected to 2 s ultrasonic action is analyzed. It is found that there are a large number of broken oxide films on the graphite side of the brazing seam. With the prolongation of ultrasonic action time, the oxide film in the brazing joint decreases gradually. When the ultrasonic wave is applied for 10 s, the oxide film in the brazing seam disappears completely and a good joint is formed. The microstructure composition of brazing joint is copper / copper-zinc alloy / silver-based solid solution copper-based solid solution / Ti C reaction layer / graphite from copper side, and the connection between solder and graphite side is mainly reactive wetting connection. Increasing ultrasonic action time and brazing temperature will promote the growth of interface reaction layer Ti C, but it can not increase continuously. It is also found that the shear properties of brazed joints are affected by the application time of ultrasonic wave. When the ultrasonic wave is applied less than 10 s, the ultrasonic wave can improve the strength of the joint, and if the ultrasonic action continues to be applied, On the contrary, the shear strength of the joint will be reduced. The optimum technological conditions are as follows: brazing temperature 820 鈩，
本文编号：2476766
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