Stress corrosion and corrosion fatigue of Zr-based bulk metallic glasses

Zr基大块金属玻璃的应力腐蚀和腐蚀疲劳

• 批准号: 224063632
• 负责人: Dr. Annett Gebert
• 金额: --
• 依托单位: Institut für Materialchemie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/224063632?language=en
• 关键词: Stress; corrosion; fatigue; Zr; based

With this project new contributions to the fundamental understanding of the stress corrosion and corrosion fatigue behaviour of bulk-glass forming alloys will be made. The mechanical properties of selected Zr-based alloys will be analyzed in normal and corrosive conditions, i.e. under anodic dissolution, passivation-repassivation regimes and cathodic hydrogen charging. The bending behavior will be tested under quasi-static, static and cyclic loadings for determination of the ultimate bending strength, the fatigue life, the crack growth rate and the fracture toughness. Aim of the study is the clarification of the crack growth behavior in a basic manner. This requires an understanding of the interactions of alloy elements with ions from the surrounding medium acting on the crack development by modifying the crack tip morphology. Since cracks initiate and grow along shear bands, the interplay of shear bands with the corrosive medium must be clarified. To that end effects of glassy alloy composition yielding different reactivity, of nano-heterogeneities guiding the shear banding as well as of surface defects determining local topographic and mechanical stress states will be studied. Multi-scale in situ and ex situ microscopic and spectroscopic analysis of crack initiation and propagation will be conducted with special focus on crack tip regions.The goal is a better understanding of the governing processes in the structure during deformation. In metallic glasses the SRO/MRO state, i.e. the individual atom bindings and topologies are most important for the mechanical properties. Changes of these states through the corrosive environments will in turn change their reaction on static and cyclic load. Nano-heterogeneities in a glassy structure represent an additional structural factor affecting the mechano-corrosive degradation process. Principle mechanistic descriptions of stress corrosion and corrosion fatigue phenomena of metallic glasses will be developed and those will be discussed in relation to established mechanisms for silicate glasses and crystalline alloys. As main contribution to the overall goal of the SPP 1594 a topology-environment-mechanical properties (TEMP) relationship will be developed based on project results and supported by results of other SPP projects. From this work strategies for alloy modifications to inhibit stress-induced corrosion phenomena will be derived leading to ultra-strong metallic glasses with high environmental resistance.

通过该项目，将对大块玻璃形成合金的应力腐蚀和腐蚀疲劳行为的基本理解做出新的贡献。选定的锆基合金的机械性能将在正常和腐蚀条件下进行分析，即在阳极溶解、钝化-再钝化状态和阴极充氢条件下。将在准静态、静态和循环载荷下测试弯曲行为，以确定极限弯曲强度、疲劳寿命、裂纹扩展速率和断裂韧性。研究的目的是从根本上阐明裂纹扩展行为。这需要了解合金元素与周围介质中的离子的相互作用，通过改变裂纹尖端形态来影响裂纹的发展。由于裂纹沿着剪切带产生和扩展，因此必须澄清剪切带与腐蚀介质的相互作用。为此，将研究产生不同反应性的玻璃态合金成分的影响、引导剪切带的纳米异质性以及确定局部形貌和机械应力状态的表面缺陷的影响。将进行裂纹萌生和扩展的多尺度原位和异位微观和光谱分析，特别关注裂纹尖端区域。目标是更好地了解变形过程中结构的控制过程。在金属玻璃中，SRO/MRO 状态（即单个原子结合和拓扑）对于机械性能最为重要。这些状态在腐蚀环境中的变化将反过来改变它们对静态和循环负载的反应。玻璃结构中的纳米异质性代表了影响机械腐蚀降解过程的另一个结构因素。将开发金属玻璃的应力腐蚀和腐蚀疲劳现象的原理机理描述，并将结合硅酸盐玻璃和晶体合金的既定机理进行讨论。作为对 SPP 1594 总体目标的主要贡献，将根据项目结果开发拓扑-环境-机械特性 (TEMP) 关系，并得到其他 SPP 项目结果的支持。从这项工作中，将导出合金改性以抑制应力引起的腐蚀现象的策略，从而产生具有高耐环境性的超强金属玻璃。