Influence of severe plastic deformation on aging of Al-Mg-Si alloys

The influence of severe plastic deformation induced by equal-channel angular pressing (ECAP) on the microstructure and aging was studied in two modified Al-Mg-Si aluminum alloys. The microstructure of both alloys after different heat treatments and deformation paths was characterized by X-ray diffraction and polarized-light microscopy. The effect of artificial aging was investigated on samples in the as-extruded condition after ECAP. The aging was monitored by hardness and electrical conductivity measurements. At higher aging temperature (170 °C), the alloys showed an increasing softening with time due to recovery or/and grain coarsening. At lower aging temperatures, the hardness remains almost constant owing to enhanced precipitation hardening.