High temperature Young's modulus of alumina short fibre reinforced Al-Si MMCs produced by liquid infiltration

Abstract

Metal matrix composites were produced with modified pressure liquid infiltration equipment using short delta-Al2O3 (Saffil) fibre preforms, containing 10, 15, 20, 25, and 30 vol.-% fibres as reinforcement and the alloy Al-12Si (wt-%) LM 13 as matrix material. The matrix alloy and the composites were subjected to standard T6 heat treatment and consequently modulus measurements were carried out at temperatures from 25 to 400 degrees C. The results showed that the modulus of elasticity of the composites in the temperature range studied gradually increased with increasing fibre volume, but decreased with temperature. As the test temperature increased all composites had an excellent retention of modulus up to 300 degrees C in such a manner that the higher the volume per cent of fibres in the composites, the better the retention of modulus. In addition, the data obtained from Young's modulus measurements over the temperature range studied were compared with theoretical results predicted by shear-lag and Nielsen-Chen models and shown to be in better agreement with those of the latter world.