Effect of cold-rolling and annealing temperature on microstructure, texture evolution and mechanical properties of FeCoCrNiMn high-entropy alloy

Abstract

This study investigates the effects of cold rolling and annealing on the microstructure, texture, and mechanical properties of FeCoCrNiMn high-entropy alloys. Utilizing vacuum induction melting, the alloy was initially cast into ingots and hot-rolled into plates, which were subsequently cold-rolled to various thicknesses and annealed at different temperatures. Microstructural analyses were conducted using X-ray diffraction and electron backscatter diffraction techniques, revealing a persistent face-centered cubic structure across all conditions. The texture evolution demonstrated a shift from Copper and S components to dominant Goss and Brass components as cold rolling intensified, suggesting the formation of Brass-type texture in FeCoCrNiMn at high deformation. Mechanical testing showed that the alloy's yield and tensile strengths significantly increased with cold rolling, reaching optimum values at ∼66 % reduction. Annealing at 750 °C enhanced both strength and ductility, primarily through grain refinement and the formation of Σ3 annealing twin boundaries, which dominated the microstructure of recrystallized grains. The study confirms that the low stacking fault energy of the alloy facilitates the activation of twinning and transformation-induced plasticity mechanisms, crucial for the observed enhancements in mechanical properties.