Incipient Oxidation and Deformation Mechanisms of the Complex Concentrated Alloy AlMo0.5NbTa0.5TiZr in the High Temperature Regime

复合高合金AlMo0.5NbTa0.5TiZr高温初期氧化与变形机制

• 批准号: 398838389
• 负责人: Dr.-Ing. Leonardo Agudo Jácome
• 金额: --
• 依托单位: Fachgebiet Struktur und Eigenschaften von Materialien
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/398838389?language=en
• 关键词: Incipient; Oxidation; Deformation; Mechanisms; Complex

The branch known as complex concentrated ‒or compositionally complex‒ alloys (CCAs) has seen a rapid development within the last ten years. These alloys contain high concentrations of all ‒or most‒ present constituents in the compositional hyperspace. CCAs have the potential for showing reduced diffusion velocities under corrosive environments, as well as an increased hardening behavior if mechanically loaded, due to the strong atomic interaction of its components. Thus, the need for stronger oxidation resistant materials in the range of high temperature load-bearing applications has opened a window for developing CCAs based on refractory elements (rCCAs). While rCCAs are usually characterized by brittle room temperature behavior, the recently developed alloy AlMo0.5NbTa0.5TiZr shows a two-fold increase of compression strengths than most equivalent commercial Ni-base superalloys, while still retaining a 10% fracture elongation. The higher compression strength and ductility of the AlMo0.5NbTa0.5TiZr rCCA are kept up to 1200°C, relative to the commercial alloys. Although coupled with a desired low density (=7.4 g/cm3) and a potential to form a protective Aluminum oxide layer under aggressive environments, compression tests remain the sole property assessed so far for the AlMo0.5NbTa0.5TiZr rCCA. The present project aims at advancing the knowledge on the response of the AlMo0.5NbTa0.5TiZr rCCA under chemical and mechanical loading conditions relevant for the high temperature realm of applications. More specifically, it is intended to study the initial high temperature damage mechanisms that occur 1) in oxidizing environments and 2) under mechanical loads. Thus, the early stages of oxidation under a controlled atmosphere representative for the gas turbine industry will be studied, i.e., humid air, as will be the deformation mechanisms found under creep and high temperature tension. In order to tackle the microstructural development under these conditions, a wide range of characterization methods will be implemented such as in-situ X-ray diffraction during high temperature oxidation, residual stress analysis, and 3D observation and reconstruction of crystalline defects by self-developed STEM stereoscopic procedures.

近十年来，复合高密度合金的分支，即成分复杂的高密度合金（CCAs）得到了迅速的发展。这些合金在组成超空间中含有高浓度的所有或大多数不存在的成分。CCA具有在腐蚀性环境下显示降低的扩散速度的潜力，以及如果机械加载，由于其组分的强原子相互作用而增加的硬化行为。因此，在高温承载应用范围内对更强的抗氧化材料的需求为开发基于耐火元素的CCA（rCCA）打开了一扇窗户。虽然rCCA通常以脆性室温行为为特征，但最近开发的合金AlMo0.5NbTa0.5TiZr显示出比大多数等效的商业镍基高温合金的压缩强度增加两倍，同时仍保持10%的断裂伸长率。AlMo0.5NbTa0.5TiZr rCCA的较高压缩强度和延展性保持高达1200°C，相对于商业合金。尽管结合了所需的低密度（=7.4 g/cm 3）和在侵蚀性环境下形成保护性氧化铝层的可能性，但压缩测试仍然是迄今为止针对AlMo0.5NbTa0.5TiZr rCCA评估的唯一性能。本项目的目的是推进知识的AlMo0.5NbTa0.5TiZr rCCA的化学和机械载荷条件下的响应相关的高温领域的应用。更具体地说，它旨在研究1）在氧化环境中和2）在机械载荷下发生的初始高温损伤机制。因此，将研究在代表燃气涡轮机工业的受控气氛下的氧化的早期阶段，即，湿空气，蠕变和高温拉伸下发现的变形机制也是如此。为了解决这些条件下的微观结构发展，将实施广泛的表征方法，如高温氧化过程中的原位X射线衍射，残余应力分析，以及通过自主开发的STEM立体程序对晶体缺陷进行3D观察和重建。