Influence of heat treatment on the properties of Al6061/albite composites

An accelerated aging response was detected in Al6061 based metal matrix composites, in age hardening, electrical resistivity, EDS diffraction, TEM, DSC and microstructural observations. The samples were subjected to aging at 32, 80, 180, and 320�C for 0.01 to 100 hours. The peak of the hardness and the resistivity values of the MMCs increased with increasing reinforcement content and ageing temperature although the MMCs precipitation kinetics (peak) in the matrix alloy is significantly accelerated due to the presence of reinforcement. It is thought that the dislocation assisted nucleation processes reduce the apparent activation energy for precipitation, and a higher nucleation density of precipitates in the composites. Changes in the properties of the composites during aging have been explained on the basis of microstructural alterations during ageing.