Response to thermal exposure of the mechanically alloyed Al/C powder blends

The present work was undertaken to investigate the response of the mechanically alloyed Al/C powder blends to thermal exposure. Carbon was introduced into Al powders via high-energy ball milling and Al4C3 particles were precipitated with a subsequent heat treatment. Al4C3 precipitation starts in the solid state and accelerates after the aluminium matrix melts. This reaction produces a very fine dispersion of carbide particles in a wide temperature range in samples milled for at least 6 h. Relatively higher nucleation rates in these samples owing to a high density of lattice defects introduced during high-energy ball milling is responsible. The fine carbide particles thus produced resist coarsening below 750 °C, but undergo substantial coarsening at still higher temperatures.