Grain refinement of Al–Zn–Mg alloy during equal channel angular pressing (ECAP)

Locally produced Al–Zn–Mg alloy was subjected to severe plastic deformation through Equal Channel Angular Pressing (ECAP) technique at temperatures of 150 °C and 200 °C. Rectangular thick-walled medium carbon steel die (?c = 450Mpa, ?y 176Mpa) with an L-shaped channel uniform configuration provide the pressing chamber used. Four ECAP passes were imposed consecutively on set samples for temperatures, characterized optical microscopy, scanning electron microscopy (SEM) x-ray diffraction (XRD). The phases identified by X-ray (XRD) using monochromatic Cu K? radiation, while vickers’ microhardness tensile tests performed mechanical properties examination. Optical micrographs showed no tangible precipitation in as cast reduced grain width bands but high °C, promoted a result slipping systems activation. SEM images as-cast exhibits dendrites 250 ± 20 ?m size ?? phase (MgZn2) precipitates inter-dendritic regions. For temperature, significant refinement achieved increased sub-grain development within boundary precipitate observed has 35 15 ?m, 25 10 8 6 first, second, third fourth respectively. However, sizes 85 50 30 5 temperature. XRD results peaks aluminum other condition growth after first pass, metastable phase. As number increases, moved towards equilibrium ? confirming transformation stable microhardness, Ultimate strength (UTS) yield different conditions respectively also increase passes. This is due dislocation density, work hardening during process.