Complex concentrated coatings: Effect of processing route on microstructural and mechanical properties

We investigated the structure-property correlation for the complex concentrated alloy (CCA) coatings prepared using different precursor powders. Al3CoCrFeNi CCA precursor powders were prepared through mechanical alloying (MA) (ball milling) and direct mixing (DM). CCA coatings were developed using microwave technique through hybrid heating approach. Coatings showed good metallurgical bonding with substrate exhibiting cellular growth structure. Microstructure for both coatings was primarily composed of A2 phase segregated with B2 phase at intercellular region. CCA coatings with different precursors showed insignificant influence on hardness, elastic modulus and cavitation erosion. Nonetheless, coating developed with MA precursor showed slightly lower fracture toughness compared to DM, mainly attributed to inherently higher fraction of intermetallic B2 phase. We showed that direct mixing is an efficient and effective route for developing CCA coatings.