Effect of Cr Dopants on the Structure and Failure Mechanism of TiAlN Multilayered Films
Taras Shevchenko National University of Kyiv, 60 Volodymyrska Str., UA-01033 Kyiv, Ukraine
Received: 17.01.2019; final version - 25.03.2019. Download: PDF
Structural features and mechanical characteristics of nanocomposite TiAlN multilayered thin films are characterized by electron microscopy, nanoindentation and atomic force microscopy. The films are deposited onto WC–Co substrates using cathodic arc method. As found, Cr dopants have an essential impact on the microstructure of samples, the morphology of cracks, and the mechanical properties of the coatings. It results in an increase in the hardness of the films studied due to disappearance of the wurtzite phase and the formation of a CrN hard f.c.c. phase. Moreover, the formation of the columnar structure and the increase in the number of bilayers, $etc.$, contribute to the additional strengthening of the film. The formation and propagation of indentation-induced cracks are sensitive to both a structure of film and its growth morphology. The primary cracks appear for all films beneath the indenter at the contact site. In columnar films, the morphology of these cracks consists of a network of short, discontinuous, irregular cracks. In fine-grained structures, the straight radial through-thickness cracks are formed. Such modification of crack patterns is attributed to the role of grain boundary sliding which is more pronounced in coarse columnar films than in nanograined materials.
Key words: thin film, cracks morphology, fracture toughness, hardness, transmission electron microscopy.
PACS: 62.20.mt, 68.37.Lp, 68.55.J-, 68.55.Ln, 68.60.Bs, 68.65.Ac
Citation: O. Nakonechna, Effect of Cr Dopants on the Structure and Failure Mechanism of TiAlN Multilayered Films, Metallofiz. Noveishie Tekhnol., 41, No. 5: 621—631 (2019)