Resubmission: High-strength, low-stress cemented carbide-steel brazed joints due to dispersed gamma-Fe-Co-Cu precipitates in the copper-rich fillet

重新提交：由于富铜焊角中分散的 γ-Fe-Co-Cu 沉淀物而形成高强度、低应力硬质合金-钢钎焊接头

• 批准号: 527885000
• 负责人: Professor Dr.-Ing. Wolfgang Tillmann
• 金额: --
• 依托单位: Lehrstuhl für Werkstofftechnologie (LWT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/527885000?language=en
• 关键词: Resubmission; strength; low; stress; cemented

The overall objective of this research project is to maximize the joint quality of the cemented carbide-maraging-steel brazed joint by consistently using all strength-increasing measures permitted by the metallurgy of the material joint system to be brazed. From the point of view of possible applications in the field of machining technology, this is done against the background of increasing the service life as well as increasing the feed forces of tools such as brazed hammer drills, cemented carbide-tipped saw blades or tool holders with large-area joining surfaces. In addition to the application of an adequate temperature-time regime and the selection of a suitable brazing material, the focus of this research project is increasingly on the introduction of a wetting-promoting Ni layer into the existing joint material system as well as on the resulting material mechanisms within the brazed seam which increase the brazed joint quality. A Ni layer applied by arc PVD to the otherwise difficult-to-wet maraging steel dissolves in the brazing melt during the brazing process and alloys the brazing zone in such a way that, after solidification, both finely dispersed gamma-Fe-Co precipitates are present in the brazing material structure and fine-seamed, brittle-phase-reduced interfacial transitions with a defect-free bond to the base materials. Two elementary material-technological factors, which are of scientific importance for this research project, are the precipitation hardenability typical for Cu-Ni-Fe alloys and the complete solubility of the elements Cu and Ni in each other. Thus, not only the morphology of the described gamma-Fe-Co phases is influenced by an adapted temperature-time profile as well as the change of the chemical composition of the brazing zone by the variation of the Ni layer work, but also the ductility of the Cu-rich matrix phase is adjusted in a targeted manner, so that a positive influence on the global composite properties is brought about. The research project is also of high technical relevance, since the choice of the high-melting solder Cu, which is commonly used for brazing carbide-steel, brings the time-temperature profile of the brazing process into line with the time-temperature transformation behavior of the maraging steel, so that the downstream tempering process results in simultaneous precipitation hardening in both the steel and the brazing material. In this process, the holistic heat transfer modes of thermal radiation and, if necessary, fabrication prevailing in the vacuum furnace are utilized, so that, in contrast to brazing processes with a local heat input (e.g. induction brazing), there is a holistic positive influence on the mechanical steel properties.

本研究项目的总体目标是通过持续使用待钎焊材料接头系统冶金学允许的所有强度增加措施，最大限度地提高硬质合金-马氏体时效钢钎焊接头的接头质量。从在机械加工技术领域中的可能应用的观点来看，这是在增加工具的使用寿命以及增加工具的进给力的背景下完成的，所述工具例如钎焊锤钻、硬质合金刀片或具有大面积接合表面的工具保持器。除了适当的温度-时间制度的应用程序和选择合适的钎焊材料，这个研究项目的重点越来越多地在现有的接头材料系统中引入润湿促进镍层，以及由此产生的材料机制内的钎焊缝，提高钎焊接头质量。通过电弧PVD施加到否则难以润湿的马氏体时效钢上的Ni层在钎焊过程中溶解在钎焊熔体中，并使钎焊区合金化，使得在固化后，在钎焊材料结构中存在细分散的γ-Fe-Co沉淀物和细缝的、脆性相减少的界面过渡，其与基体材料无缺陷地结合。两个基本的材料技术因素，这是科学的重要性，为这项研究项目，是沉淀硬化典型的Cu-Ni-Fe合金和完全溶解的元素Cu和Ni在对方。因此，不仅所描述的γ-Fe-Co相的形态受到适应的温度-时间曲线的影响以及通过Ni层功的变化而改变钎焊区的化学组成，而且富Cu基质相的延展性也以有针对性的方式被调节，从而对整体复合材料性能产生积极影响。该研究项目也具有很高的技术相关性，因为高熔点焊料铜的选择，这是常用的钎焊碳化物-钢，使钎焊过程的时间-温度曲线符合马氏体时效钢的时间-温度转变行为，使下游回火过程的结果在钢和钎焊材料中同时沉淀硬化。在该过程中，利用了热辐射的整体热传递模式，并且如果必要的话，利用了真空炉中普遍存在的制造，使得与具有局部热输入的钎焊过程（例如感应钎焊）相比，对钢的机械性能具有整体的积极影响。