Influence of glass topology and medium range order on the deformation mechanisms in borosilicate glasses, a multiple length scale approach

玻璃拓扑和中程有序对硼硅酸盐玻璃变形机制的影响，一种多长度尺度方法

• 批准号: 224502470
• 负责人: Professor Dr.-Ing. Karsten Durst
• 金额: --
• 依托单位: Otto-Schott-Institut für Materialforschung (OSIM)
• 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 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/224502470?language=en
• 关键词: Influence; glass; topology; medium; range

In this project, the influence of topology and medium range order on the mechanical properties of the NBS1 and NBS2 type borosilicate glasses is studied following a multiple length scale approach. For NBS1, the degree of polymerisation depends on the pressure during glass preparation. The glass state can be further modified by local treatments like laser or ion irradiation. In NBS2, the medium range order of the glass can be changed in the bulk as well as on the local scale, despite the fact that the basic glass forming entities remain the same. After processing, the topology of the glass is characterised by Infrared and Raman spectroscopy. Moreover, by using small additions of structure indicator ions, such as Mn2+ or Cr3+, it is possible to detect structural changes by fluorescence microscopy.In conjunction with the preparation and characterisation of the different glass states, their mechanical properties are studied in a multi-scale approach. With in-situ micro-cantilever deformation experiments and pillar compression tests in the SEM, as well as the nanoindentation and impact testing methods, the elastic, plastic and fracture properties of the materials are assessed over a range of length scales and deformation conditions. Plastic flow in the glass and densification effects will be studied by indentation, as cracking can be suppressed, due to the confinement provided by the surrounding material. By changing the indenter or the specimen geometry (Berkovich, cube-cornerindenter or micropillars and small glass spheres), the effect of the stress state or sample volume on the deformation mechanism is studied. In this context, micropillars provide a test in which the hydrostatic stress component is minimised. Using microcantilevers, the maximum bending strength and, in the case of notched cantilevers, the local fracture toughness of glasses with different topology is also accessible. By varying the strain rate and test temperature in impact and indentation testing, the dynamics of the fracture and plastic deformation mechanisms in the different glass structures is quantified. After deformation, the activated densification and flow mechanisms are characterised by spectroscopy and microscopy (AFM, SEM and TEM) of the plastically deformed volumes.Of particular interest are the structural parameters which govern the length scales in the deformation and damage behaviour of the glasses. By comparison of the observed deformation mechanisms with the results on bulk metallic glasses or other glass systems, general concepts for the understanding of localised deformation and fracture behaviour in glasses will be obtained.

在这个项目中，拓扑和中范围顺序对NBS1和NBS2型硼硅酸盐玻璃的机械性能的影响进行了多长度尺度方法研究。对于NBS1，聚合的程度取决于玻璃制备过程中的压力。玻璃状态可以通过激光或离子照射（例如激光或离子辐照）进行进一步修饰。在NBS2中，尽管基本的玻璃形成实体保持不变，但玻璃的中等范围可以在散装和本地规模上更改。处理后，玻璃的拓扑结构以红外和拉曼光谱法为特征。此外，通过使用少量的结构指标离子（例如MN2+或CR3+），可以通过荧光显微镜检测结构变化。与不同玻璃状态的制备和表征结合使用，以多尺度方法研究了它们的机械性能。在SEM中的原位微抗验证剂变形实验和支柱压缩测试以及纳米识别和冲击测试方法中，材料的弹性，塑性和断裂特性在长度范围内评估。玻璃中的塑料流量将通过凹痕研究，因为周围材料提供的限制，可以抑制裂纹。通过更改凹痕或样品几何形状（Berkovich，Cube-Cornerindenter或Micropillars和小玻璃球），应研究应力状态或样品体积对变形机制的影响。在这种情况下，微柱提供了一个测试，其中将静液压应力成分最小化。使用微型磁场，最大弯曲强度，对于缺口悬臂，也可以访问具有不同拓扑的玻璃杯的局部断裂韧性。通过改变撞击和压痕测试的应变速率和测试温度，可以量化不同玻璃结构中断裂和塑性变形机制的动力学。变形后，激活的致密化和流动机制的特征是塑料体积的光谱和显微镜（AFM，SEM和TEM）的特征。特别感兴趣的是结构参数，该结构参数控制着玻璃的变形和损坏行为的长度尺度。通过将观察到的变形机制与散装金属玻璃或其他玻璃系统的结果进行比较，将获得了解玻璃中局部变形和断裂行为的一般概念。