Akademik Veri Yönetim Sistemi
Surfaces and Interfaces, cilt.94, 2026 (SCI-Expanded, Scopus)
High-entropy alloy (HEA) coatings produced by electro-spark deposition (ESD) exhibit strongly non-equilibrium microstructures that are highly sensitive to substrate chemistry. In the current study, substrate-driven micro-alloying during ESD of CoCrFeMnNi (Cantor HEA) on aluminum, copper, and titanium substrates was systematically investigated. Deposition on aluminum resulted in severe cathodic erosion, a high degree of dilution and the formation of an in-situ Al-matrix composite reinforced by dispersed HEA particles, exhibiting moderate hardness (∼175 HV) but localized micro-cracking induced by thermal expansion mismatch. In contrast, the copper substrate promoted extensive interdiffusion with a moderate level of dilution and the formation of a crack-free, dual-phase FCC structure with Cu-Mn-rich precipitates, leading to enhanced hardness (∼270 HV). Deposition on titanium caused extreme microalloying with a minimal dilution of HEA elements into the substrate, however with significant Ti liquid infiltration into the coating and stabilization of hard BCC-B2 and intermetallic phases, resulting in the highest hardness (∼553 HV) but localized cracking and interfacial voids. Despite these defects, the HEA/Ti coating exhibited superior corrosion resistance in 3.5 wt. % NaCl solution, with a corrosion current density of ∼9 × 10⁻⁸ A.cm⁻², compared with ∼2 × 10⁻⁶ A.cm⁻² for the HEA/Cu coating due to the formation of stable passive TiO2 film besides the amorphous nature of this coating. Thermodynamic CALPHAD analysis supported the experimentally observed substrate-dependent phase evolution. These results demonstrate that substrate chemistry plays a decisive role in tailoring the microstructure and functional performance of ESD-deposited HEA coatings.