铝基复合材料的瞬间液相连接研究

【作者】 王笃雄；

【导师】 王隆太； 刘剑虹；

【作者基本信息】 扬州大学 ， 机械制造及其自动化， 2003， 硕士

【摘要】 碳化硅颗粒增强铝基复合材料作为性能优良的新一代工程结构材料，具有高比强度、比模量、耐高温、耐腐蚀等一系列的优点。但是铝基复合材料的焊接性能差，很难形成高强度的接头，成为该种材料走向实用化的严重障碍。为使其获得更广泛的工业应用，迫切需要开发实用可靠的连接技术，所以研究碳化硅颗粒增强铝基复合材料的连接具有重要的意义。 本文在综合国内外研究的基础上，认为瞬间液相连接能实现铝基复合材料的良好连接。Z．Li等人在研究瞬间液相连接铝基复合材料的接头颗粒偏聚现象和机械性能时指出，采用合适的中间层厚度可以有效防止接头区域颗粒偏聚现象。另外，研究表明，氧化膜在无压瞬间液相连接时成为影响接头性能的主要因素。本文选择10μm的铜箔作为中间层，进行铝基复合材料的瞬间液相连接，通过试验确定了获得良好接头的最佳工艺参数。实验结果表明：施加2MPa的压力，连接温度853K，保温时间120分钟，平均接头剪切强度可达156.5MPa，达到母材的75.6％。 本文首次提出使用磁控溅射法制备瞬间液相连接的中间层。一种是直接沉积法，另一种是溅射去除氧化膜再沉积法。研究了磁控溅射法在待连接表面沉积中间层的工艺参数以及不同的中间层制备方法对TLP连接接头组织和性能的影响。接头平均剪切强度分别为158.7MPa、169.1MPa，达到了母材剪切强度的76.7％、81.7％。 利用金相显微镜、扫描电镜、能谱仪、X射线衍射分析仪，结合Al-Cu二元合金相图及扩散理论，分析了接头区域的形貌、组织、成分、相组成，以及断口形貌、成分。研究了瞬间液相连接时，压力、连接温度、保温时间等工艺参数对接头组织和性能的影响规律，为能实现碳化硅颗粒增强铝基复合材料的良好连接打下理论基础并提供实验依据。 待连接表面通过磁控溅射法沉积铜膜作为中间层进行瞬间液相连接，得到的接头强度与铜箔中间层进行瞬间液相连接得到的接头强度相当，而使用磁控溅射法去除待连接表面氧化膜后沉积铜膜作为中间层进行瞬间液相连接的接头强度提高7.6％左右。该强度在目前报导中尚不多见，且接头区域没有夹杂物，接头组织几乎不能分辨，与母材组织相似。 研究表明，使用磁控溅射法去除连接材料表面的氧化膜后进行瞬间液相连接可以提高接头强度，改善接头区域的组织和性能。采用适当的压力进行瞬间液相连接时，铝基复合材料表面的氧化膜已不是影响接头性能的主要因素。更多还原

【Abstract】 Aluminum based metal matrix composite (Al MMCs) materials with SiC particle reinforced as excellent capability engineering materials have high strength, good wear resistance, excellent elevated temperature, high stiffness. However the welding property of AL MMCs is poor, it’s difficult to obtain high joint strength. The application of Al MMCs has been restricted by the low joint strength. In order to apply the Al MMCs into industry, it’s necessary to study the reliable bonding technology. It’s paramount significance to investigate the bonding method of SiCp/6061Al MMCs.The particle segregation in the joint region hasn’t been observed when TLP bonding of Al MMCs using 10 m thickness copper foil, according with the theory of Z. Li. The effect of joint property is the oxidation on surface of the AI MMCs. When TLP bonding with pressure can avoid the effect of oxidation, obtain excellent joint property. Oxidation wasn’t observed in the joint region by microanalysis. The process of transient liquid phase(TLP) bonding of 6061A1 MMCs using 10urn thickness copper foil has been studied. By the experiment, the best technology parameters for the TLP bonding have been obtained. The result is that, pressure of 2MPa, bonding temperature of 853K, holding time of 120 minutes, the average shear strength is up to 156.5MPa, 75.6% of the shear strength of base metal.It’s the first time to deposit copper film on surface of Al MMCs by magnetron sputtering, and embed Al MMCs into the sputtering region of Al target. Inlaid target sputtering to remove oxide scale on surface of Al MMCs at first, then another copper target sputtering, copper film was deposited on the inlaid target. The technology parameters of deposition on surface of Al MMCs have been studied. TLP bonding of 6061A1 MMCs using deposition copper film as interlayer with the best parameters, the joint shear strength is up to 158.7MPa, 169.1MPa, 76.7%, 81.7% of the base metal shear strength.The microstructure, structure, composition, phase of joint region, and the microstructure and composition of fracture have been analyzed using the equipment of Metallurgical microscope, SEM, EDS, XRD and binary eutectic phase diagram for the Al-Cu system and diffusion theory. Effects of parameters (pressure, temperature, holding time) of TLP bonding of Al MMCs on the joint shear strength have been studied. Experimental and theoretical basis for joint with excellent mechanical properties havebeen provided.Copper has been deposited on surface of the Al MMCs as interlayer by magnetron sputtering, TLP bonding of Al MMCs with these interlays, the joints shear strength of TLP bonding using deposited film was as much as the joint shear strength of TLP bonding using Cu foil. Removing the oxidation on the surface before deposition, Copper was coated by magnetron sputtering as TLP bonding interlayer. The shear strength was 7.6% higher. There wasn’t any oxidation in the joint region, and the structure was as same as the structure of base metal.When TLP bonding with proper pressure, the oxidation on the surface of Al MMCs wasn’t the primary effect of the properties of the joint. TLP bonding using the deposited film markedly increased the joint shear strength更多还原