Investigation of precipitation-hardenable-, copper-base-alloys, for brazing of materials with highly different coefficients of thermal expansion.

在各种应用中，传统的金属材料对力学性能、热性能和耐腐蚀性的要求越来越高，是无法满足的。由于这一事实，使用高性能的部分或全部陶瓷材料和延性金属支撑体的组合变得越来越重要。为了创建具有特定性能的高强度接头，通常需要使用基于熔接的工艺来连接这些部件。在这里，铜焊得到了广泛的应用。阻碍所创建的接头的全部潜力使用的一个困难是在铜焊过程中残余应力的独特发展。这是由于所用材料的热膨胀系数经常显著不同造成的。为了获得应力的降低，使用了延性的填充金属。然而，这些合金抵抗外力的强度有限。因此，理想的填充金属应该既有足够的延展性来缓解残余应力，又有足够的韧性来创建高强度的接头。只要有合适的合金并且冶金机理是已知的和理解的，可硬化合金就可以满足这些要求。这项拟议工作的主要任务是在铜焊的背景下分析可硬化合金。与这种合金的铸造相反，显微组织的演变经历了复杂得多的过程。尤其是多组分体系中的扩散动力学现象必须引起人们的高度重视。要做到这一点，将对选定的合金进行单独的分析，并与一个衬底以及整个接头进行相互作用。使用这种尝试可以识别和确定衬底对硬化行为的影响。所获得的知识将应用于项目的最后阶段，以加入与应用相关的部件，以揭示新合金的潜力，并将其与传统填充金属进行比较。这两项研究的结果相结合，为可能以应用为导向开发用于所述特殊应用的填充金属提供了深厚的科学基础。

In various applications, the rising requirements concerning the mechanical and thermal properties as well as corrosion resistance cannot be met by conventional metallic materials. Due to this fact, the use of combinations of high-performance partially or fully ceramic materials and ductile metal supporters becomes increasingly important. In order to create high-strength joints with specific properties it is often necessary to join these parts with a fusion based process. Here, brazing is broadly applied. A difficulty, which hinders the use of the full potential of the created joints, is the distinctive development of residual stresses during brazing. This is the result of the often significantly different coefficients of thermal expansion of the used materials. To obtain a reduction of the stresses, ductile filler metals are used. However, these alloys possess only limited strength against external forces. Consequently, an ideal filler metal should be both ductile enough to relax residual stresses and tough enough to create high-strength joints. These requirements can be met by hardenable alloys, as long as there are suitable alloys available and the metallurgic mechanisms are known and understood. The main task of the proposed work is the analysis of hardenable alloys in the context of brazing. Contrary to the casting of such alloys, the microstructural evolution undergoes much more complex processes. Especially the diffusion-kinetics phenomena in multi-component system have to be considered intensively. To do so, selected alloys will be analyzed on their own, in interaction with one substrate as well as in the whole joint. The effects of the substrates on the hardening behavior can be identified and determined using this attempt. The gained knowledge will be applied in the final stages of the project to join application-related components in order to reveal the potential of the new alloys and compare it to conventional filler metals. The combination of the results of both investigations provides a profound scientific fundament for possible application-oriented development of filler metals for the described special applications.