Fatigue-resistance enhancements by glass-forming metallic films

Zr-based glass-forming metallic films were deposited on a 316 L stainless steel and a Ni-based alloy by magnetron sputtering. Four-point-bending fatigue tests were conducted on those coated materials. Results showed that the fatigue life and fatigue-endurance limit of the materials could be considerably improved, and the enhancements varied with the maximum applied stresses and the substrates. The reduction of the surface roughness after film deposition, good adhesion between the film and the substrate, and the high hardness, strength, and good ductility of the glass-forming metallic film, are the major factors for the fatigue-resistance enhancements. A micromechanical model is developed to illustrate the mechanisms of fatigue-resistance enhancements through the interaction between the amorphous film and the substrate slip bands.