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

本项目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。本文以离心铸造和射频溅射两种工艺为研究对象，提出了一种新的分析方法来计算离心铸造过程中的非稳态温度、颗粒弥散和应力场。所提出的程序是通过有限元建模的方法开发的。利用该模型对铝合金为基材和碳化硅颗粒组成的材料体系进行了数值模拟。模拟结果与实验观测结果基本吻合。建立了另一种纤维增强金属基复合材料的有限元模型。对碳化硅纤维增强铝合金进行了数值模拟，得到了基体-纤维界面附近的应力集中。实验结果表明，碳纤维表面的碳涂层改善了碳化硅连续纤维增强碳化硅陶瓷的力学性能。利用射频磁控溅射装置在玻璃衬底上沉积了氧化铝和碳化硅薄膜。利用超显微硬度计对溅射膜的硬度进行了测试。结果表明，两种陶瓷薄膜的硬度均随射频输出功率的增加而降低。尝试用分子动力学方法估算溅射薄膜的内应力场。溅射粒子的分子动力学采用硬球三维模型。根据经验信息，假设溅射粒子团簇随着射频输出功率的增加而增大。利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.