Executive Summary : | Complex concentrated alloys (CCAs), particularly face-centered cubic (FCC) equiatomic CoCrFeMnNi, have gained significant scientific interest. CoCrFeMnNi offers higher low-cycle fatigue (LCF) resistance compared to common FCC steels due to its excellent combination of strength and plastic strain accommodation ability. To improve CoCrFeMnNi fatigue resistance, its SFE can be adjusted by altering its chemical composition. Higher SFE facilitates dislocation cross-slip, while lower SFE promotes planar slip and extensive deformation accommodation. This work aims to test two non-equiatomic CCAs (Cr26Mn20Fe20Co20Ni14 and Cr14Mn20Fe20Co20Ni26) with distinctly different SFE. The alloys will be synthesized via vacuum induction melting and casting, followed by homogenization, cold working, and annealing treatments to optimize microstructures. Tensile and LCF testing will be conducted on the optimized alloys to understand their mechanical response. EBSD and TEM investigations will be conducted on as-fabricated and deformed samples to understand deformation and damage mechanisms under monotonic and cyclic loading conditions. The influence of strain amplitude and strain rate on the underlying microstructural evolution will be evaluated. The outcome of this work will contribute to the development of novel fatigue-resistant CCAs for automobile, aerospace, and energy-related applications. |