表面纳米化铜低温扩散焊接机理研究
发布时间：2018-07-27 18:41
【摘要】：扩散焊接技术属于压焊的一种,与传统焊接方式相比,具有焊接接头质量好、焊接温度低、引起组织性能劣化程度小等优点。而且扩散焊接可以实现物理化学性能差别较大的异种材料之间的焊接,甚至可以焊合相互不溶解或在熔焊时会产生脆性金属间化合物的异种材料,同时因此有着很好的应用前景。表面纳米化技术是一种比较新的表面改性技术,与传统改性技术相比也有着无可比拟的优势,比如技术简单、形成的纳米层不易剥落分离、不改变基体状态等。特别是金属材料经表面纳米化后表现出很多优异的性能,比如表面强度、硬度提高;耐腐蚀性和耐磨性提高;疲劳性能改善;表面原子扩散的能力增强等。利用纳米材料的高扩散性,将表面纳米化技术与扩散焊技术相结合,可以得到显著提升材料扩散焊接接头质量的效果。为了论证表面纳米化技术对扩散焊接接头组织和性能的影响,本文以纯铜为研究对象,利用表面机械滚压技术对纯铜试样进行表面纳米化处理,并利用光学和扫描电子显微镜、显微硬度计、万能试验机等测试手段,分析了表面纳米化技术对纯铜表层性能的影响,并从扩散焊接接头的显微组织特征、显微硬度、剪切强度等方面,分析了表面纳米化技术对纯铜扩散焊接接头质量的影响,并通过添加镍中间层来研究镍原子在纯铜试样中的扩散行为。本文首先利用表面机械滚压(SMR)技术,对纯铜试样进行表面纳米化处理,结果表明,随着滚压次数的增加,纯铜表层晶粒逐渐被细化,变形区域也逐渐加深。在处理20次后,纯铜表层的晶粒达到纳米级别,晶粒尺寸从表层至心部呈梯度分布,纯铜试样表层的显微硬度值也显著提高,是基体的1.5倍。通过在300℃、400℃和500℃下分别对未经表面纳米化处理的纯铜母材和经表面纳米化处理的纯铜试样进行扩散焊接试验,结果表明,相同温度下,经过表面纳米化处理的纯铜试样焊缝结合程度好,焊缝接头界面处晶粒较为细小且显微硬度值较高,而且焊接接头的剪切强度明显高于未经表面纳米化处理的纯铜母材试样的。随着温度从300℃升到400℃,两种试样的剪切强度都有所增高,但500℃时,由于组织劣化,剪切强度不再增加,甚至有所下降。添加镍中间层后,300℃时,镍中间层中铜镍原子的相互扩散很少,随着温度的升高,镍中间层逐渐消失,500℃时,铜镍原子的相互扩散更加充分。
[Abstract]:Compared with the traditional welding method, the diffusion welding technology has the advantages of good welding quality, low welding temperature and small deterioration of microstructure and properties. Moreover, diffusion welding can be used to weld dissimilar materials with different physical and chemical properties, or even to weld dissimilar materials that are insoluble to each other or produce brittle intermetallic compounds during fusion welding. At the same time, it has a good application prospect. Surface nanocrystalline technology is a relatively new surface modification technology. Compared with traditional surface modification technology, it has unparalleled advantages, such as simple technology, the formation of nano-layer is not easy to peel off, do not change the state of the matrix, and so on. Especially after surface nanocrystalline, metal materials show many excellent properties, such as surface strength, hardness improvement, corrosion resistance and wear resistance improvement, fatigue performance improvement, surface atomic diffusion ability enhanced, and so on. By using the high diffusivity of nanomaterials and combining the surface nanocrystalline technology with the diffusion welding technology, the quality of the diffusion welded joints of the materials can be significantly improved. In order to demonstrate the effect of surface nanocrystalline technology on the microstructure and properties of diffusion welded joints, the surface nanocrystalline treatment of pure copper samples was carried out by surface mechanical rolling technique, and optical and scanning electron microscopy (SEM) were used to investigate the effect of surface nanocrystallization on the microstructure and properties of diffusion welded joints. The influence of surface nanocrystalline technology on the surface properties of pure copper was analyzed by means of microhardness tester and universal tester, and the microstructure, microhardness and shear strength of diffusion welded joints were analyzed. The effect of surface nanocrystalline technology on the quality of pure copper diffusion welded joints was analyzed, and the diffusion behavior of nickel atoms in pure copper samples was studied by adding nickel interlayer. In this paper, surface nanocrystalline treatment of pure copper samples is carried out by surface mechanical rolling (SMR) technique. The results show that with the increase of rolling times, the surface grains of pure copper are gradually refined and the deformation area is gradually deepened. After 20 times of treatment, the grain size of the surface layer of pure copper reaches nanometer level, and the grain size is gradient distribution from the surface layer to the center. The microhardness of the surface layer of pure copper sample also increases significantly, 1.5 times as much as that of the matrix. The diffusion welding experiments were carried out at 300 鈩，
本文编号：2148795
[Abstract]:Compared with the traditional welding method, the diffusion welding technology has the advantages of good welding quality, low welding temperature and small deterioration of microstructure and properties. Moreover, diffusion welding can be used to weld dissimilar materials with different physical and chemical properties, or even to weld dissimilar materials that are insoluble to each other or produce brittle intermetallic compounds during fusion welding. At the same time, it has a good application prospect. Surface nanocrystalline technology is a relatively new surface modification technology. Compared with traditional surface modification technology, it has unparalleled advantages, such as simple technology, the formation of nano-layer is not easy to peel off, do not change the state of the matrix, and so on. Especially after surface nanocrystalline, metal materials show many excellent properties, such as surface strength, hardness improvement, corrosion resistance and wear resistance improvement, fatigue performance improvement, surface atomic diffusion ability enhanced, and so on. By using the high diffusivity of nanomaterials and combining the surface nanocrystalline technology with the diffusion welding technology, the quality of the diffusion welded joints of the materials can be significantly improved. In order to demonstrate the effect of surface nanocrystalline technology on the microstructure and properties of diffusion welded joints, the surface nanocrystalline treatment of pure copper samples was carried out by surface mechanical rolling technique, and optical and scanning electron microscopy (SEM) were used to investigate the effect of surface nanocrystallization on the microstructure and properties of diffusion welded joints. The influence of surface nanocrystalline technology on the surface properties of pure copper was analyzed by means of microhardness tester and universal tester, and the microstructure, microhardness and shear strength of diffusion welded joints were analyzed. The effect of surface nanocrystalline technology on the quality of pure copper diffusion welded joints was analyzed, and the diffusion behavior of nickel atoms in pure copper samples was studied by adding nickel interlayer. In this paper, surface nanocrystalline treatment of pure copper samples is carried out by surface mechanical rolling (SMR) technique. The results show that with the increase of rolling times, the surface grains of pure copper are gradually refined and the deformation area is gradually deepened. After 20 times of treatment, the grain size of the surface layer of pure copper reaches nanometer level, and the grain size is gradient distribution from the surface layer to the center. The microhardness of the surface layer of pure copper sample also increases significantly, 1.5 times as much as that of the matrix. The diffusion welding experiments were carried out at 300 鈩，
本文编号：2148795
本文链接：https://www.wllwen.com/kejilunwen/jinshugongy/2148795.html
教材专著
