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将玻璃的化学组成、结构和热机械性能之间的关系深深植根于科学概念的动机。我们的目标是开发一个模型，使定量探索的组成空间的地区具有出色的机械性能，并随后在材料设计中使用。该模型应针对多组分氧化物玻璃的整体机械整体性能。它从工作假设的等效结构短程有序集团在这样的玻璃，和相应的结构中发现的等化学结晶状态。这一假设在热化学性质方面得到了很好的证实，然而，在机械性质方面尚未得到利用，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，这是一种基于量子力学的从头算方法;它旨在评估晶体结构和性质，以及理解为什么某些结构在其性质方面脱颖而出。这是，第二，一个热力学的方法，针对评估单组分玻璃和等化学晶体之间的差异方面的现象学的数量，并对这些数据的叠加多组分玻璃矩阵的属性。在此，项目意义上的“多”通常是指在大多数工业玻璃产品中发现的> 5种功能性氧化物组分。MgO-CaO-Al_2O_3-SiO_2-P_2O_5系统是组成基础。该项目设想的实验工作的目的首先是对选定的单晶与其等化学对应物之间的差异进行现象学评估。由于这些差异最敏感地反映在低热热容的差异上，因此应进行低热微量热测定（外部合作）。单组分玻璃的机械整体性质的实验测定也是为了同样的目的。这些性能应通过脉冲激励技术进行声学测定。同样的技术将被应用于广泛验证多组分基质的模型预测。材料设计模型的实用性应在项目结束时在少数情况下得到证明。