Experimental and numerical engineering of novel eutectic high melting Mo-Si-Ti alloys processed by additive manufacturing: microstructure, texture and ensuing properties

通过增材制造加工的新型共晶高熔点 Mo-Si-Ti 合金的实验和数值工程：微观结构、织构和后续性能

• 批准号: 424801257
• 负责人: Professor Dr.-Ing. Martin Heilmaier
• 金额: --
• 依托单位: Institut für Angewandte Materialien - Werkstoffkunde (IAM-WK)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/424801257?language=en
• 关键词: Experimental; numerical; engineering; novel; eutectic

The proposed study aims at a combined experimental and modeling engineering approach for developing novel eutectic alloys within the Molybdenum-Silicon-Titanium system. Multi-phase refractory metal (RM) silicide alloys are considered to be very promising candidates for ultrahigh temperature structural applications beyond currently used Ni-base superalloys. However, because of their rather (i) high melting point and (ii) brittle-to-ductile transition temperature they are difficult to process in complex shaped parts using conventional equipment. Therefore, a still novel bottom-up processing method called additive manufacturing (AM) is applied aiming at understanding the elementary mechanisms for this far from equilibrium process governing microstructural development utilizing texture formation and phase field modeling. Additionally, these alloys usually suffer from a mid-temperature phenomenon called “pesting”, the spontaneous sublimation of RM-based oxides. Specifically, employing selected electron beam melting (SEBM) allows the production of parts in a protective (high vacuum) environment at elevated powder bed temperatures which makes SEBM the best choice for manufacturing of “clean” and crack-free samples of oxidation-sensitive alloy systems. In own preliminary work we could demonstrate that even conventionally processed, i.e. arc-melted, fully eutectic Mo27-Si20-Ti53 (composition given in at.%) possesses attractive creep properties and simultaneously does not show “pesting”, in other words it reveals already satisfying oxidation resistance. It was concluded that both these properties benefit from the rather fine and lamellar microstructure. Since AM is known to be a manufacturing process exhibiting high cooling rates and thermal gradients, we anticipate even finer and likely far from equilibrium microstructures on the one hand and crystallographic texture formation on the other. The properties of such microstructures are hitherto unknown and will be explained based on elementary physical metallurgy mechanism. Thus, this proposal reflects a combined effort by colleagues with mutually supplementing competences in the fields of AM of high temperature structural materials, texture formation and phase field simulation.

拟议的研究旨在建立实验和建模工程方法，用于在钼 - 硅质系统中开发新型电子合金。多相耐火金属（RM）硅胶合金被认为是超高温度结构应用的非常有希望的候选物，而不是当前使用的Ni-base Superalloys。但是，由于它们的（i）高熔点和（ii）脆性到脱氧的过渡温度，因此使用常规设备很难在复杂的零件中处理。因此，应用了一种名为添加剂制造（AM）的新型自下而上的处理方法，旨在理解这种远离质地形成和相位场建模的微观结构发展的平衡过程的基本机制。此外，这些合金通常会遭受中等温度的现象，称为“杵”，这是基于RM的氧化物的赞助升华。具体而言，采用选定的电子束熔化（SEBM）允许在高架粉末床温度下生产受保护（高真空）环境中的零件，这使得SEBM成为制造“清洁”和无裂纹氧化合金系统样品的最佳选择。在自己的初步工作中，我们可以证明，即使是经常处理的，即弧形融化的，完全的共晶MO27-SI20-TI53（at。％给出的组成）具有有吸引力的蠕变特性，并且很容易显示出“植根性”，换句话说，它已经揭示了已经满足氧化抗性的。得出的结论是，这两种属性都受益于相当细和层状微结构。由于已知AM是一种具有高冷却速率和热梯度的制造过程，因此我们预计一方面会更细，可能远离平衡微观结构，另一方面却远离了晶体学纹理。此类微观结构的特性是隐藏的，将根据基本物理冶金机制进行解释。这就是该提案反映了同事在高温结构材料，纹理形成和相位场模拟的AM领域相互补充能力的共同努力。