Laser cladding of high-entropy alloys is an effective surface-strengthening technology, yet the coating formation mechanism still requires further optimization. In this work, FeCoNiCrCu high-entropy alloy powder and a 45-steel substrate were adopted to investigate laser-cladding behavior under four representative process states: under melting, baseline, high-energy over melting, and high powder-feeding rate. The powder was designed for equiatomic fraction; the nominal mass fraction of each element was 20 wt%, which deviates from strict equiatomic ratio. The results demonstrate that the under melting condition triggers incomplete powder melting and coating defects with a porosity of 4.23 %. Excessive heat input under the high-energy condition yields a high substrate dilution rate of 37.26 % and enlarges the heat-affected zone. A high powder-feeding rate induces elemental segregation. Under the baseline condition, the molten pool spreads uniformly, defects are suppressed, and elemental diffusion is sufficient, achieving the minimum porosity of 0.32 % and the optimal interfacial shear strength of 426.24 MPa. The high-energy over melting specimen (Condition 3) reaches an average hardness of 339.62 HV, though this process brings obvious substrate over-melting risk. The as-deposited coating consists of FCC and BCC solid-solution phases, whereas laves and σ phases precipitate after annealing. This study reveals the coupling effects of process parameters on coating morphology and phase evolution and provides guidance for process optimization of such quinary high-entropy-alloy laser-cladding systems.
