Investigation and enhancement on bonding by cold bulk metal forming processes

块状金属冷成形工艺粘合的研究和增强

• 批准号: 227710263
• 负责人: Professor Dr.-Ing. Peter Groche
• 金额: --
• 依托单位: Max-Planck-Institut für Eisenforschung GmbH (MPIE)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/227710263?language=en
• 关键词: Investigation; enhancement; bonding; cold; bulk

Nowadays, keywords like energy efficiency and lightweight construction are ubiquitously present in literature. In working towards realizing these goals, lightweight construction materials such as aluminum are usually applied. However, the high mechanical requirements often exceed the material strength. Thus, a combination of different materials with different physical properties (e.g. aluminum and steel) has shown promising results. Cold pressure welding has proven to be a suitable process for joining.To obtain a sound bond high surface enlargement and contact normal stresses are necessary. To increase bond strength a matching of the initial strengths of the joining partners was found to be useful in the first funding period. Furthermore, it can be stated that the surface preparation has a crucial effect on the bond formation and strength. Surface preparation by turning a preform shows unfavorable results. This is related to a bulging of the native surface layers in the valley during the forming process and is the reason why surface enlargement is hindered in these areas. Additionally, further mechanical and chemical surface treatment processes were investigated according to their influence on bond formation. In particular brushing and etching lead to suitable results. To clarify and further analyze the bond formation mechanisms, the joining seam is investigated by transmission electron microscopy and electron energy loss spectroscopy. It is shown that no intermetallic phases are produced during the process, but a reaction layer composed of aluminum oxide is formed. It was also proven that this reaction layer does not originate from the native oxide layer of the joining materials. According to current findings, the bond between iron and aluminum is based on the aluminum oxide generated during the forming process. In order to facilitate a transfer of the current results into an industrial application, a tool for lateral extrusion is designed to allow for the generation of planear material compounds.During the third period further measures like an adjusted residual stress distribution and an investigation of the enclosed void volume of the surface will be taken to increase the bond strength between the materials. Also, the forming mechanism of the reaction layer and its influence on the bond strength will be studied. To transfer the knowledge into a broad industrial application, the reproducibility of the process with minimum variance is targeted. Also, the use of other metal combinations with this process will be investigated. A test bench for torsional testing will be designed to examine the specimens under realistic loads.

如今，文献中存在着无处不在的能源效率和轻巧结构的关键字。在朝着实现这些目标的努力时，通常会应用轻质的建筑材料，例如铝。但是，高机械要求通常超过材料强度。因此，不同材料与不同物理特性（例如铝和钢）的组合已显示出令人鼓舞的结果。人们证明，冷压焊接是一个合适的连接过程。要获得高表面增大和接触正常应力。为了提高债券的力量，在第一融资期间发现了加入合作伙伴的初始优势的匹配。此外，可以说表面制备对键形成和强度具有至关重要的影响。通过旋转预成式的表面制备显示不利的结果。这与在成型过程中山谷中天然表面层的膨胀有关，这就是为什么在这些区域阻碍表面增大的原因。此外，根据其对键形成的影响，研究了进一步的机械和化学表面处理过程。特别是刷牙和蚀刻会导致合适的结果。为了澄清和进一步分析键形成机制，通过透射电子显微镜和电子能量损耗光谱研究了连接缝。结果表明，在此过程中未产生金属间相，但是形成由氧化铝组成的反应层。还证明，该反应层不是源自连接材料的天然氧化物层。根据目前的发现，铁和铝之间的键基于成型过程中产生的氧化铝。为了促进当前结果将当前结果转移到工业应用中，侧向挤出的工具旨在允许生成计划材料化合物。在第三个时期，诸如调整后的残余应力分布以及对表面的封闭空隙体积的研究将用于提高材料之间的键强度。同样，将研究反应层的形成机理及其对键强度的影响。为了将知识转移到广泛的工业应用中，针对最小差异的过程的可重复性。同样，将研究其他金属组合在此过程中的使用。将设计用于扭转测试的测试台，以检查在逼真的载荷下的样品。