| Metal matrix composites(MMC) reinforced on Al₂O₃ fibre are gaining increasing attention for structural application. However, the data base concerning its mechanical properties and microstructural characterization remains limited. Al₂O₃ fibre(FP-fibre from Dupont) reinforced Al -2.5Li composite has been investigated in the present study. Continuous fibre Al₂O₃/Al-2.5Li composites with the 0°and 90° direction were used for the investigation. Processing of the material was performed by vacuum melt infiltration. Tensile and compressive tests were performed for mechanical characterization. In order to get sufficiently good results, a special MMC related test equipment was designed. The best results were achieved when cylindrical hourglass shaped specimens were used. Fatigue testing of the metal matrix composites showed that a pronounced improvement of the fatigue behaviour could be achieved with the fibre reinforcement. Transmission electron microscopy was performed in order to study the fibre/matrix interface. Li addition increased the wettability of the fibre in the matrix, because of the formation of two compounds in the interfaces, namely, α-LiAlO₂ and LiAl_5O_8 spinel. Precipitation free areas around the fibres containing any δ`particles, which in turn are present in the matrix, were found. |
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