In Situ Tailoring of FCC Ductile Phases for High‐Strength Wear‐Resistant Crack‐Free W‐Based Metallic Coatings

ABSTRACT Tungsten is inherently brittle and particularly prone to thermal stress concentration and crack formation during additive manufacturing processes such as laser cladding, which severely limits its engineering applications as a coating material. To address this issue, this study proposes an in situ toughening strategy involving the introduction of an FCC‐structured ductile phase to suppress crack formation and enhance the crack resistance of W‐based metallic coatings. The results show that the coating is composed of a W solid solution, a γ‐(Fe, Ni) ductile phase, (Fe, Ni) 3 W 3 C carbide, and a small amount of W 6 Fe 7 intermetallic compound. The in situ‐formed γ‐(Fe, Ni) phase is distributed in the interdendritic zones of the W solid solution and serves as a ductile phase that effectively alleviates the thermal stress concentration during solidification through localized plastic deformation, enabling the fabrication of a crack‐free coating. In addition, the obtained coating has an average hardness of 606 HV, approximately 2.4 times greater than that of the substrate. Its coefficient of friction and wear rate are significantly reduced, demonstrating excellent wear resistance and promising potential for engineering applications.