Simulation of the microstructure evolution in the brazing gap during reactive air brazing II

反应空气钎焊过程中钎焊间隙微观结构演变的模拟 II

基本信息

批准号：
164190245
负责人：
Dr. Markus Apel
金额：
--
依托单位：
Access e.V.
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2014-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/164190245?language=en
关键词：
Simulation microstructure evolution brazing gap

项目摘要

For the fabrication of metal-ceramic components, "Reactive Air Brazing" (RAB) has emerged as a joining process with high potential. The mechanical properties of a reactive air brazed joint are often limited by structural changes and the formation of oxide phases at the interface between the base material and the brazing alloy. Experimental investigations of brazing joints with Ag-Cu braze alloys show that in BSCF ceramic a reaction zone may form, which is associated with the penetration of Cu-and Co-containing melt along grain boundaries. At the interface to Cr-containing steels Cu and Cr-containing oxides are found. Morphology and thickness of such reaction zones affect the failure under mechanical load.The aim of this project is to model the formation of such reaction zones and to simulate the kinetics of the microstructure evolution for reactive air brazing with Ag-Cu braze alloys quantitatively. The simulation should help to identify those processes that control the formation kinetics, e. g. diffusive transport of oxygen or cupper, or the mobility of phase boundaries. A semi-quantitative understanding of the microstructure formation may lead to new ideas how the thickness of the undesired reaction zones can be influenced by a change in the alloy composition or the process conditions, e.g. by applying different oxygen partial pressures.In the model development results from the first phase of the project can be used. So far, the effect of the oxygen intake on phase formation and solidification kinetics of Ag-Cu braze alloys could be simulated quantitatively. The phase-field model has been extended to calculate DSC traces. This allows a quantitative comparison between the simulated microstructure evolution and measured DSC scans. Furthermore, computer-aided thermodynamics and the phase-field method will be used.In particular, the following points will be addressed: Simulation of the melting process and accompanied phase formation for the braze alloy, the interaction between the liquid braze alloy and BSCF ceramic, as well as reaction and phase formation at the interface between the molten Ag-Cu alloy and Cr-containing steel. A comprehensive thermodynamic database is not available for the materials involved. Based on available literature data and appropriate approximations a simplified thermodynamic description shall be developed and calibrated using the experimental results of the project partners. Thus, this project also provides a methodological contribution towards a thermodynamic approach for the modeling of joining processes for dissimilar materials.

为了制造金属陶瓷组件，“反应性空气爱”（RAB）已成为具有高潜力的连接过程。反应性空气悬挂关节的机械性能通常受结构变化和在基本材料与铜合金之间界面处的氧化物相形成的限制。用AG-CU铜合金对悬挂关节进行的实验研究表明，在BSCF陶瓷中，反应区可能形成，这与Cu and Co-Concontration沿晶界的熔融融化有关。在接口到含Cr的钢铜的界面和含Cr的氧化物。这种反应区域的形态和厚度会影响机械载荷下的故障。该项目的目的是建模这种反应区域的形成，并模拟微观结构演化的动力学，以定量地用AG-CU Braze Alloys进行反应性空气。模拟应有助于确定控制形成动力学的过程，e。 g。氧或铜的扩散转运，或相边界的迁移率。对微观结构形成的半定量理解可能会导致新的想法，如何通过合金组成或过程条件的变化（例如通过应用不同的氧部分压力。在模型开发中，可以使用项目的第一阶段。到目前为止，可以定量模拟氧气摄入量对Ag-Cu Braze合金的相形成和凝固动力学的影响。相位场模型已扩展以计算DSC迹线。这允许在模拟的微观结构演化与测量的DSC扫描之间进行定量比较。此外，将使用计算机辅助的热力学和相位场方法。尤其将要解决以下几点：熔融过程的仿真和伴随的铜合合金相伴随的相位形成，液体乳液合金和BSCF陶瓷之间的相互作用，以及在熔融Ag-Cu Alloy和Cr-Cunoy和Cr-Ch-Contage和Cr and cr interface interfuction interfuction interfuct和相位形成之间的相互作用。涉及的材料无法使用全面的热力学数据库。基于可用的文献数据和适当的近似值，应使用项目合作伙伴的实验结果来开发和校准简化的热力学描述。因此，该项目还为热力学方法做出了方法论贡献，以建模连接不同材料的过程。