PREPARATION AND MECHANICAL-PROPERTIES OF AC8A ALUMINUM-ALLOY COMPOSITE REINFORCED WITH POTASSIUM TITANATE WHISKER

An AC8A aluminum alloy matrix composite reinforced with highly crystal lized potassium titanate whisker having a crystallite size of 76 nm wa s fabricated by squeeze casting. Heat hardening behavior and mechanica l proper ties were examined on the obtained composites whose Mg conten ts in the matrix were from 0.7 to 1.9 mass%. The Mg content and hardne ss of the composite were uniform at any locations. The composite whose Mg content in the matrix were 1.7 mass% solutionized at 803 K showed the highest strength value at room temperature and 573 K, respectively . And the Young's modulus was as high as 138 GPa. The decrease in stre ngth during exposure at up to 573 K was not observed. In particular, t he properties of the obtained composite were found to be useful for th e elevated temperature materials.