Crack‐free Fe‐based metallic glass coatings by extreme high‐speed laser cladding and their phase features correlated toughness

Fe‐based metallic glass (MG) coatings draw great attentions due to their excellent mechanical properties. The recently developed extreme high‐speed laser cladding (EHLC) provides a promising method for their fabrication but its application is challenged by pronounced cracking behavior. In this study, crack‐free Fe‐based MG coatings were prepared for the first time via EHLC. The effects of precipitated phases (i.e., (Fe, Ni), (Fe, Ni) 3 P and Fe 7 C 3 ) on cracking in the Fe–Ni–P–C MG coatings were investigated. The results demonstrate that cracks can be effectively suppressed by enhancing the coating’s toughness. The correlation between the precipitated phases and the coating toughness was quantitatively evaluated. The toughness can be improved by the ductile precipitates and the MG matrix, while the brittle precipitates, particularly the Fe 7 C 3 phase, significantly reduce the toughness. By introducing a proper ductile crystalline phase of (Fe, Ni) and suppressing the formation of brittle phases, cracking in the Fe‐based MG coatings was effectively suppressed during the EHLC process.