Model for the prediction of thermomechanical bulk properties of multicomponent oxide glasses based on a combined quantum mechanical and thermodynamic approach

基于量子力学和热力学相结合的方法预测多组分氧化物玻璃的热机械整体性能的模型

• 批准号: 224505286
• 负责人: Professor Dr. Reinhard Conradt
• 金额: --
• 依托单位: Lehrstuhl für Festkörper- und Quantenchemie
• 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 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/224505286?language=en
• 关键词: Model; prediction; thermomechanical; bulk; properties; Model; prediction; thermomechanical; bulk; properties

The present project is inspired by the motivation to deeply root the understanding of the relation among chemical composition, structure, and thermomechanical properties of glasses in scientific concepts. The objective is the development of a model enabling quantitative exploration of compositional space for areas with outstanding mechanical properties, and its consequent use in materials design. The model shall be directed towards the bulk mechanical bulk properties of multicomponent oxide glasses. It starts from the working hypothesis of equivalency of structural short-range order groupings in such glasses, and the corresponding structures found in the isochemical crystalline states. This hypothesis is well substantiated with respect to thermochemical properties, however, yet unexploited with respect to mechanical properties, in part because of a lack of understanding – or even availability – of fundamental data for the crystals. The envisaged model attemps to establish the wide bridge from single crystals to multicomponent glasses by a combined approach. This is, firstly, a quantum mechanics based ab initio approach; it is directed towards the assessment of crystal structures and properties as well as towards an understanding why certain structures stand out with respect to their properties. This is, secondly, a thermodynamic approach directed towards assessing the differences between one-components glasses and isochemical crystals in terms of phenomenological quantities, and towards the superimposition of such data to the properties of multicomponent glass matrices. Here, “multi” in the sense of the project refers to typically > 5 functional oxide components as found in most industrial glass products. The system MgO-CaO-Al2O3-SiO2-P2O5 is depicted as compositional basis. The experimental work envisaged for this project aims, firstly, at a phenomenological assessment of the differences between selected single crystals and their isochemical counterparts. As these differences are most sensitively reflected by the differences in low-T heat capacities, low-T microcalorimetry shall be performed (external cooperation). The experimental determination of the mechanical bulk properties of one-component glasses serves the same purpose. These properties shall be determined acoustically by impuls excitation technique. The same technique will be applied to extensively verify model predictions for multicomponent matrices. The usefulness of the model for materials design shall be demonstrated at the end of the project for a few cases.

本项目的灵感来自于深入了解科学概念中眼镜的化学组成，结构和热力学特性之间关系之间关系的动机。目的是开发一个模型，从而为具有出色的机械性能的区域及其在材料设计中的使用中进行定量探索。该模型应针对多组分氧化物玻璃的块状机械体积。它始于此类玻璃中结构短订单组的等效性以及在等化晶体状态中发现的相应结构。但是，关于热化学性质的假设得到了很好的证实，但是，在机械性能方面，这是出乎意料的，部分原因是缺乏对晶体基本数据的理解（甚至可用性）。设想的模型试图通过组合方法建立从单晶到多组分玻璃的宽桥。首先，这是一种基于量子机械的AB始于方法。它是针对晶体结构和特性的评估，以及理解某些结构在其性质方面脱颖而出的原因。其次，这是一种热力学方法，用于评估现象学量的一体配件玻璃和同化晶体之间的差异，以及将这种数据叠加到多组分玻璃材料的性质中。在这里，从大多数工业玻璃产品中发现的，“多”是指通常> 5个功能性氧化物成分。系统MGO-CAO-AL2O3-SIO2-P2O5被描述为复合基础。首先，为该项目设想的该项目的实验工作旨在对选定的单晶及其等级化学对应物之间的差异进行现象学评估。由于这些差异最为敏感地反映了低T热容量的差异，因此应进行低T微钙化法（外部合作）。一个组件玻璃的机械体积特性的实验确定具有相同的目的。这些属性应通过激发冲动技术准确地确定。相同的技术将应用于广泛验证多组分物品的模型预测。材料设计模型的有用性应在项目结束时在几种情况下进行。