基于过渡层的铜—钼复合工艺研究

发布时间：2018-04-26 02:30

  本文选题：铜 + 钼　； 参考：《南京理工大学》2017年硕士论文

【摘要】：铜以其优良的导电、导热、机加工等性能在越来越多的领域中发挥着重要作用,是当今社会最重要的有色金属之一。但在一些有电弧烧蚀、摩擦磨损的工况条件下,铜合金的应用受到限制,使用寿命缩短。为了解决这一问题,可以采用在铜表面复合钼的方法来增强铜合金的耐电弧烧蚀、耐磨损性能。由于铜、钼在固相和液相下均完全不互溶,复合铜钼是焊接领域的一个技术难题。本文分别采用Ni箔、Ti箔和AgCuTi钎料作为中间层来焊接复合Cμ、Mo金属。分析了材料焊接接头的微观结构、力学性能和断口组织。讨论了焊接温度、焊接时间、焊接压力等工艺参数对结合强度、接头微观结构的影响。分别得到不同中间层时的最佳工艺参数,并分析了 Ti中间层的焊接过程。研究结果表明:正交试验结果表明:采用Ni箔中间层时,在焊接温度800℃、焊接时间30min、焊接压力7MPa的条件下,扩散焊接复合的剪切强度最高,达到了 46.7MPa;通过极差分析和方差分析,三个主要工艺因素中,影响力显著性排序为:焊接温度焊接压力焊接时间。焊接复合接头断裂在Ni中间层中靠近钼侧的Mo-Ni互扩散区域,为脆性断裂。AgCu钎料不能润湿金属Mo,而在加入Ti元素后,钎料和Mo有较好的润湿性。这主要因为在反应过程中,Ti和Mo能形成固溶体界面,使得Mo与钎料之间的界面能降低,液态钎料才能能够在Mo表面润湿。随着焊接温度升高,Mo侧的形核数目增多,组织变得致密;Cu侧的柱状组织向中间层延伸,变得粗大。在880℃下保温30min时,接头的剪切强度达到了 89.3MPa。采用Ti箔中间层时,随着温度和压力的增大,焊接强度逐渐增大;随着焊接时间的增加,焊接强度先增大再减小。在焊接过程中,接头处Cu和Ti之间会发生共晶反应生成多种金属间化合物。在880℃下,生成的液相较少,焊接后中间层Ti箔仍然存在,生成的金属间化合物残留在接头孔隙处,界面处有明显未焊透缺陷;930℃和1030℃下,生成的液相较多,大都被挤出焊接区域,接头成形较好。以焊接接头剪切强度为评价指标,最佳焊接复合工艺为1030℃、30min、5MPa,剪切强度达到了 201.5MPa;若兼顾剪切强度与焊接变形,最佳焊接复合工艺为1030℃、30min、3MPa,剪切强度达到了 180.3MPa。
[Abstract]:Copper plays an important role in more and more fields because of its excellent electrical conductivity, heat conduction and machining properties. It is one of the most important nonferrous metals in the society today. However, under the condition of arc ablation and friction wear, the application of copper alloy is limited and the service life is shortened. In order to solve this problem, the arc ablation resistance and wear resistance of copper alloy can be enhanced by using molybdenum compound on copper surface. Because copper and molybdenum are completely insoluble in solid and liquid phase, composite copper and molybdenum is a technical problem in welding field. In this paper, Ni foil Ti foil and AgCuTi filler metal are used as interlayer to weld composite C 渭 Mo metal. The microstructure, mechanical properties and fracture structure of welded joints were analyzed. The effects of welding temperature, welding time and welding pressure on bonding strength and microstructure of joints are discussed. The optimum process parameters of different interlayers were obtained, and the welding process of Ti interlayer was analyzed. The results show that when the interlayer of Ni foil is used, the shear strength of diffusion welding composite is the highest under the condition of welding temperature 800 鈩，

本文编号：1804094