Oxide dispersion strengthened and oxidation resistant vanadium alloys

氧化物弥散强化抗氧化钒合金

• 批准号: 494809307
• 负责人: Privatdozent Dr.-Ing. Mathias Galetz
• 金额: --
• 依托单位: Institut für Werkstoff- und Fügetechnik (IWF)
• 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/494809307?language=en
• 关键词: Oxide; dispersion; strengthened; oxidation; resistant

Vanadium-base alloys are promising candidates for the development of novel high temperature materials due to, among others, their highly specific mechanical strength. This can be achieved by alloying with elements that cause precipitation hardening (such as Si and B) or with oxide particles, so-called ODS particles (oxide dispersoids). However, optimal mechanical properties require a V solid solution matrix in the materials microstructure. This matrix in turn is extremely vulnerable in oxidising environments. The reason is that the formation of V2O5, which – in contrast to the pure metal (Ts (Vanadium) = 1919 °C) – is liquid at temperatures above ca. 690°C. This oxidation behaviour is the reason why vanadium-base alloys have not been considered for high temperature application until now. To make matters worse, vanadate changes very easily between different oxidation states, which extremely accelerates the high temperature corrosion of Ni-, Co- or Fe-base materials, especially if it is present in a molten form. This also excludes an application of currently available vanadium alloys in combination with these materials.In order to make vanadium alloys applicable at high temperatures, a completely new approach of oxidation protection is proposed with simultaneous oxide particle strengthening: Using Mg- and Ca-containing oxide particles to produce oxidation-resistant ODS-V-Si alloys. Introduced in sufficient amounts, the ODS particles are expected to prevent the formation of liquid phase at high temperatures. At the same time we expect a strengthening effect of the particles, which is to be quantified in the potential application range of such alloys from ambient temperature to 1100°C.The purpose of the project is to clarify (1) up to which volume fraction of MgO, CaO or magnesium orthosilicate particles homogeneous microstructures can be formed in vanadium materials, (2) which concentration of MgO, CaO or magnesium orthosilicate is required to prevent liquid phase formation or to trigger a self-protecting mechanism, (3) how much of a strengthening effect can be achieved by adding oxide dispersoids and how the ODS particles affect the creep behaviour of vanadium alloys. Accompanying investigations are planned in order to systematically characterise the powder and alloy systems in terms of their composition and their microstructure and, subsequently, their oxidation behaviour. The main focus lies on determining the optimal ratio between ODS particles and vanadium solid solution in relation to oxidation resistance and mechanical properties. Thus, a completely new approach of alloy design is taken in order to improve oxidation resistance and mechanical properties at the same time.

钒基合金具有高比机械强度等优点，有望成为开发新型高温材料的候选材料。这可以通过与引起沉淀硬化的元素(如Si和B)或与氧化物颗粒，即所谓的消耗臭氧层物质颗粒(氧化物分散体)合金化来实现。然而，要获得最佳的力学性能，材料的微观组织中需要V固溶体。而这种基质在氧化环境中又极其脆弱。原因是V2O5的形成，与纯金属(ts(Vadium)=1919°C)不同，V2O5在高于690°C的温度下是液态的，这种氧化行为是直到现在还没有考虑高温应用的钒基合金的原因。更糟糕的是，钒酸盐很容易在不同的氧化态之间发生变化，这极大地加速了镍、钴或铁基材料的高温腐蚀，特别是当它以熔融形式存在时。这也排除了现有的钒合金与这些材料的结合应用。为了使钒合金在高温下适用，提出了一种全新的氧化物颗粒同时强化的氧化保护方法：使用含镁和含钙的氧化物颗粒来制备抗氧化性的ODS-V-Si合金。如果引入足够的量，消耗臭氧层物质颗粒有望防止在高温下形成液态。本项目的目的是阐明(1)在钒材料中，何种体积分数的氧化镁、氧化钙或正硅酸镁颗粒可以形成均匀的微结构，(2)需要何种浓度的氧化镁、氧化钙或正硅酸镁颗粒来防止液相形成或触发自保护机制，(3)添加氧化物分散体可以达到多大的强化效果，以及消耗臭氧层物质颗粒如何影响钒合金的蠕变行为。计划进行相应的调查，以便系统地描述粉末和合金系统的组成和微观结构，以及随后的氧化行为。主要研究重点是确定在抗氧化性和力学性能方面最优的金属颗粒与钒固溶体之间的比例。因此，为了同时提高合金的抗氧化性和力学性能，采用了一种全新的合金设计方法。