Effect of heat treatment on the microstructure and properties of laser cladding Cu-containing 316L stainless steel coating

This study systematically investigated the effects of solution and aging heat treatment on the microstructure, mechanical properties, and corrosion resistance of Cu-containing 316L stainless steel coatings fabricated by laser cladding. The results indicated that while heat treatment preserved the primary phase constitution and grain morphology of the coating, it significantly altered the precipitation behavior. Solution treatment induced Cr 23 C 6 carbide precipitation along grain boundaries, while subsequent aging treatment promoted homogeneous dispersion of nanoscale ε-Cu precipitates within the γ-Fe matrix. These microstructural changes produced distinct mechanical responses. Solution treatment provided slight hardness improvement through combined solid solution strengthening and Cr 23 C 6 precipitation effects, whereas solution-plus-aging treatment achieved enhanced hardness and wear resistance via ε-Cu precipitation strengthening. The electrochemical behavior analysis revealed an inverse trend. Solution treatment improved the corrosion resistance by facilitating the formation of protective Cr 2 O 3 in the passive film, while aging treatment degraded performance through multiple mechanisms. The precipitation of ε-Cu phases disrupted the stability and continuity of the passive film, and the incorporation of Cu 2+ increased the defect density. Furthermore, the galvanic coupling between ε-Cu precipitates and γ-Fe matrix also accelerated localized corrosion. • Effects of solution and aging on laser-clad 316L-Cu coatings were studied. • Solution induced Cr 23 C 6 precipitation, while aging promoted ε-Cu dispersion. • Aging improved hardness and wear resistance via ε-Cu precipitation strengthening. • Solution enhanced corrosion resistance, while aging degraded it.