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

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理解科学概念中玻璃的化学成分、结构和热机械性能之间的关系，目标是开发一种模型，能够定量探索具有出色机械性能的区域的成分空间。该模型应针对多组分氧化物玻璃的整体机械性能，该模型从此类玻璃中结构短程有序群的等效性的工作假设以及发现的相应结构开始。在然而，这一假设在热化学性质方面得到了充分证实，但在机械性质方面尚未得到利用，部分原因是缺乏对晶体的基本数据的理解，甚至缺乏可用性。通过组合方法建立从单晶体到多组分玻璃的宽桥。首先，这是一种基于量子力学的从头计算方法；它旨在评估晶体结构。其次，这是一种热力学方法，旨在评估单组分玻璃和等化晶体在唯象量方面的差异，并将此类数据叠加到玻璃的属性上。此处，项目意义上的“多”通常指大多数工业玻璃产品中存在的 > 5 种功能性氧化物成分。 MgO-CaO-Al2O3-SiO2-P2O5 被描述为组成基础，该项目设想的实验工作首先旨在对选定的单晶及其等化学片段之间的差异进行现象学评估，因为这些差异最敏感地反映在。低T热容量的差异，应进行低T微量热法（外部合作）单组分玻璃的机械整体性能的实验测定具有相同的目的。特性应通过脉冲激励技术来确定。相同的技术将用于广泛验证多组分基质的模型预测，该模型对于材料设计的有用性将在项目结束时在一些情况下得到证明。