Mechanical characterisation and microstructure study of Al-Zn alloy processed by equal channel angular pressing combined with heat treatment

In the present investigation the mechanical properties and microstructural studies of heat treated and severely plastic deformed in equal channel angular processed by route 'A' of Al-Zn alloys were studied. The alloys were heated to a temperature of 550 degrees C for two hours to achieve solid solution temperature before Equal Channel Angular Processing (ECAP), which improved the grain refinement. The ageing treatment at a temperature of 190 degrees C up to 20 hours improved the precipitates which will obstruct the motions of dislocation. The experimental results revealed that yield strength and microhardness increased with increasing holding time up to 16 hr with reduced elongation due to the precipitation of GP zones and dispersion of eta, eta, T and E within the Aluminium matrix. The microstructural structures revealed the three strengthening mechanisms namely dislocation strengthening, precipitation strengthening and grain refinement.