Formation of Metal-and Ceramic-Matrix Composites and Its Computer-Aided Materials Design Based on Interface Properties

本课题以金属基和陶瓷基复合材料为研究对象，建立了计算机辅助材料设计。本文主要分析了离心铸造和射频溅射两种成型工艺。提出了一种新的离心铸造过程中温度、颗粒分散和应力场的非稳态分析方法。采用有限元建模的方法开发了该程序。利用该模型对以铝合金为基体和碳化硅为颗粒的材料体系进行了模拟。模拟结果与实验观测结果基本吻合。建立了另一种评价纤维增强金属基复合材料性能的有限元模型。对sic纤维增强铝合金进行了模拟，得到了基体-纤维界面附近的应力集中情况。实验结果表明，碳纤维涂层改善了SiC连续纤维增强SiC陶瓷的力学性能。在射频磁控溅射装置中，将氧化铝和碳化硅薄膜沉积在玻璃衬底上。采用超显微硬度试验机对溅射膜的硬度进行了测试。结果表明，两种陶瓷膜的硬度均随射频输出功率的增大而减小。本文尝试用分子动力学方法估计溅射薄膜内部应力场。溅射粒子的分子动力学采用硬球三维模型。根据经验信息，假设随着射频输出功率的增加，溅射颗粒团簇越大。用所提出的分析方法对实验结果进行了定性解释。

In this project, metal-and ceramic-matrix composites were investigated to establish the computer-aided materials design. The formation processes to be analyzed in this work were the centrifugal casting and RF sputtering processes.A new analytical method was proposed to evaluate the unsteady state on temperature, particle dispersion and stress fields during the centrifugal casting process. The proposed procedure was developed by means of finite element modeling. A simulation using the proposed model was conducted for the material system of aluminium alloy as matrix and SiC particle. The simulated results almost coincided with the experimental observation. Another finite element model was developed to evaluate fiber reinforced metal matrix composites. The simulation was conducted on the SiC-fiber reinforced Al alloy to show stress concentration around the matrix-fiber interface. The experimental results revealed that the carbon coating on fiber improved the mechanical properties in SiC continuous fiber reinforced SiC ceramics.Thin films of alumina and silicon carbide were deposited on the glass substrate in an RF magnetron spattering apparatus. The hardness, as a mechanical property, of the sputtered films were evaluated by using an ultra-microscopic hardness testing machine. It was found that the hardness decreased with increasing RF output power in both ceramic films. A molecular dynamics approach was tried to estimate the internal stress field in sputtered film. A hard-sphere 3D model was adopted in the molecular dynamics of sputtered particles. Based on empirical information, cluster of spattered particles was assumed to be larger with increasing RF output power. The experimental result was explained qualitatively by using the proposed analytical method.