Fritze, S.; Hahn, R.; Aboulfadl, H.; Johansson, F.O.L.; Lindblad, R.; Böor, K.; Lindblad, A.; Berggren, E.; Kühn, D.; Leitner, T.; Osinger, B.; Lewin, E.; Jansson, U.; Mayrhofer, P.H.; Thuvander, M.: Elemental distribution and fracture properties of magnetron sputtered carbon supersaturated tungsten films. Surface & Coatings Technology 477 (2024), p. 130326/1-7
10.1016/j.surfcoat.2023.130326
Open Access Version
Abstract:
The combination of strength and toughness is a major driving force for alloy design of protective coatings, and nanocrystalline tungsten (W)-alloys have shown to be promising candidates for combining strength and toughness. Here we investigate the elemental distribution and the fracture toughness of carbon (C) alloyed W thin films prepared by non-reactive magnetron sputtering. W:C films with up to ~4 at.% C crystallize in a body-centered-cubic structure with a strong ?hh0?texture, and no additional carbide phases are observed in the diffraction pattern. Atom probe tomography and X-ray photoelectron spectroscopy confirmed the formation of such a supersaturated solid solution. The pure W film has a hardness ~13 GPa and the W:C films exhibit a peak hardness of ~24 GPa. In-situ micromechanical cantilever bending tests show that the fracture toughness decreases from ~4.5 MPa·m1/2 for the W film to ~3.1 MPa·m1/2 for W:C films. The results show that C can significantly enhance the hardness of W thin films while retaining a high fracture toughness.