The Effect of Grain Size Gradient on Plastic Deformation of Gradient Aluminum

Grain size gradient materials exhibit superior strength and ductility due to their multiscale microstructures. A dislocation-based multiscale model was applied to study the effect of grain size gradient on the flow stress and deformation of gradient Aluminum. It is found that the grain orientation has a slight effect on the macroscopic behavior of gradient Aluminum, but without a strong texture fiber, such effect is neglectable. The strength depends not only on the average grain size but also on the grain size gradient. By varying the grain size gradient in the region connecting finest 200 nm grains and coarse grains in tens of microns, we found that the plastic flow stress is inverse proportional to the grain size gradient. A smooth transit could lead to a redistribution of the stress concentration and strain localization. The results on the deformation of different grain size gradients Aluminum shed light on processing gradient materials with an improved combination of strength–ductility.