Inhomogeneous Deformation and Microstructural Evolution during the Hot Deformation of Al-4.98%Mg

Abstract

Plane strain channel die compression (PSC) deformation has been carried out on Al-Mg alloys with Mg contents of 0.1 to 5 % at 350°C, and the deformed microstructures characterised by channelling contrast backscattered electron imaging (BSE), secondary electron imaging (SE) and high resolution electron backscatter diffraction (EBSD). Measurements of orientation spread and misorientation gradient obtained from EBSD maps have been used to quantify the microstructural inhomogeneity developing in the 4.98 % Mg alloy. The results are consistent with inhomogeneous plasticity with more deformation occurring in the grain boundary regions. In-situ FEGSEM hot deformation experiments on the Al-4.98 % Mg alloy have provided evidence of stress driven boundary migration at low strains.

Quantitative study of grain refinement in Al–Mg alloy processed by equal channel angular pressing at cryogenic temperature

“…The misorientation gradients of major and minor axes increase sharply as equivalent strain accumulates from 1 to 4. The misorientation gradient of minor axis at ECAP 4 passes is 4.6°/μm, which is 23 times of the same alloy after hot compression [20]. The misorientation gradient of minor axis is significantly higher than the major axis in 1-4 passes of ECAP.…”

“…Large misorientation gradients have been observed in hot compressed Al-Mg alloys by TEM [19] and EBSD [20]. However, the microstructure after ECAP, especially processed at cryogenic tempera-ture, is much more complicated.…”