Abstract
Research and development of advanced high performance SiC/Al-alloy composite materials was performed with the emphasis on correlations between microstructures and mechanical properties. Microstructural investigation was mainly carried out by means of electron microscopy (SEM, TEM, STEM-EDX). Mechanical property was evaluated by tensile test at room temperature and 723 K.
As the scoping study, SiC reinforced composite plates with varieties of alloys were investigated. Mainly from the stand point of interfacial reaction A1050 was selected as matrix material for the next step.
SiC/A1050 preform wires were produced by liquid metal infiltration method. At the first stage, formation of shrinkage cavities and thermal degradation of fiber strength were the dominant issues. Minimizing these issues by process controlling with the help of new ceramic nozzle for drawing and purification of matrix Al, the tensile strength of preform wire has reached to the value of simple rule of mixture.
Al-Ni alloys were selected to improve high temperature strength of the composites. The Microstructural design concept of this system is to utilize matrix strengthening by in-situ composite and to improve interfacial microstructures. TEM inspections of the composites proved the realization of this concept. As the results, the tensile strength of SiC/A1-5.2% Ni preform wires successfully reached to 1.7 GPa at R. T. and 1.5 GPa at 723 K.
