Revealing the relationship between microstructures, textures, and mechanical behaviors of cold-rolled Al0.1CoCrFeNi high-entropy alloys

Here we reveal and discuss the relationship among microstructures, textures, and mechanical behaviors of Al0.1CoCrFeNi high-entropy alloys (HEAs) after cold rolling and annealing. The initially coarsen grains display profuse lamellar-structured slip bands upon cold rolling to 50% reduction with mostly extending vertically to the rolling direction. Meanwhile, cold rolling facilitates the evolutions of Goss ({011} <100>) and Brass ({110} <112>) component textures in the low stacking fault energy (SFE) HEAs accompanying with the formation of deformation twins. Interestingly, the rolling strengthen HEAs exhibit novel anisotropies of yield strength and strain hardening associating more with the direction of the slip lines and twins rather than the rolling-induced preferred orientations, attributing to the easier dislocations glide in between the slip lines and twins than across them. The microstructural characters including dislocation density, slip lines, and twins are quantitatively evaluated, which demonstrates that the dynamic grain refinement contributes much more for the overall strength, compared to the increased dislocation density. A lower strength (370 MPa for yield and 733 MPa for failure) and exceptional ductility (similar to 55%) are achieved in the annealed samples with random grain orientations.

Automated summary

The study reveals the complex relationship among microstructures and mechanical behaviors of Al0.1CoCrFeNi high-entropy alloys after cold rolling and annealing. Cold rolling induces grain coarsening and formation of lamellar slip bands, while facilitating texture evolution and novel strength anisotropy. However, the overall strength is more influenced by dynamic grain refinement rather than increased dislocation density.