Fraunhofer Project Center for Coatings in Manufacturing PCCM

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  • Publication
    Correlation between the wear behavior of coated cemented carbide tools and coatings properties assessed by nano-indentations, nanoand micro-impact tests
    ( 2016)
    Bouzakis, Konstantinos-Dionysios
    ;
    Charalampous, Panagiotis
    ;
    Bouzakis, Emmanouil
    ;
    Kotsanis, Tilemachos
    ;
    Skordaris, Georios
    ;
    Michailidis, Nikolaos
    ;
    Klocke, Fritz
    ;
    Bergs, Thomas
    ;
    Ottersbach, Michael
    ;
    Busch, Marc
    The application of appropriate PVD coatings on cemented carbide tools plays an important role for achieving an enhanced milling performance. In the conducted investigations, two different PVD coatings with an overall thickness of about 3.5 mm were deposited on cemented carbide tools possessing a fine, or a normal grain size structure. The coated tools were applied in milling hardened steel and Ti-Al alloy. Nano-indentations supported by appropriate FEM-algorithms for the results evaluation were carried out for determining the stress-strain curves of the employed coatings and substrates. The films brittleness was assessed by conducting nano-impact tests. The fatigue behavior of the applied coatings under dynamic loads was evaluated via impact tests at various temperatures and impac t force durations similar to those developed during milling. Based on the determined coating properties, the attained tool wear results were sufficiently explained.
  • Publication
    Coating's applications: Assessment of coatings' brittleness by nano-impact tests
    ( 2013)
    Bouzakis, K.-D.
    ;
    Skordaris, G.
    ;
    Gerardis, S.
    ;
    Bouzakis, E.
    In the described investigations, nano-impact tests were conducted on PVD film surfaces previously subjected to micro-blasting at different pressures for constant duration. Micro-blasting improves the film mechanical properties due to the induced residual compressive stresses into the coating structure. The film mechanical properties as well as the ratio of the film yield to rupture stress (SY/SM) grow up to a certain micro-blasting pressure. The augmentation of SY/SM ratio increases simultaneously the film brittleness. For analyzing the effect of the SY/SM ratio on the film brittleness, a multi-layer 3D-FEM model simulating the nano-impact test was developed, employing the LS-DYNA software package. The FEM calculated results converge sufficiently with the attained experimental ones. Based on these results, the film's failure initiation and evolution can be predicted depending on the SY/SM ratio of the individual film layers.