Structural, interface texture and toughness of TiAlN/CNx multilayer films

• Published in: Materials characterization 2021-08, Vol.178, Article 111301
• Main Authors: Liu, Dongguang, Ruan, C.F., Zhang, Peng, Ma, Haoran, Liang, Yan, Tu, Jiangping
• Format: Article
• Language: English
• Subjects: Interfaces; Layer thickness; Sputtering; Thin films; Transformation
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2021.111301

Microstructure evolution study of TiAlN/CNx multilayer films with similar single layer thickness (the thickness of individual TiAlN layer: LTiAlN, LTiAlN/LCNx = 1) in the range of 0.9 nm to 13.7 nm shows that the structure of the TiAlN/CNx-MFs changes with the change of LTiAlN. TiAlN/CNx-MFs with LTiAlN of 0.9 nm exhibit a nanocomposite structure with embedded nano-sized crystalline TiAlN particles in the matrix. Due to the template effect of the TiAlN layers when LTiAlN is 2.6 nm, the CNx layers will partially crystallize and grow coherently with the TiAlN layers. Analysis of the different relationships between the TiAlN/CNx interface reveals one type of orientation relationship between the fcc TiAlN and crystalline CNx layers: (111) TiAlN‖(111) C3N4. Interfaces of the TiAlN/CNx are sharp but with the expansion of the TiAIN lattice spacing and the shrinking of CNX relative to itself, the lattice spacing will vary near the interface region. Further increasing LTiAlN, the CNx layers will exhibit completely amorphous structures and slowly lose their coherent interfaces, triggering a rapid decline in hardness and toughness. Maximum hardness of the MFs is 27.2 GPa when the LTiAlN is 0.9 nm, while the fracture toughness of the MFs with LTiAlN of 2.6 nm is almost 1.5 times that of the other MFs. To obtain high hardness and enhanced toughness in MFs, crystallization of CNx layers and coherent growth are required. •TiAlN/CNx-MFs with LTiAlN of 0.9 nm exhibit nanocomposite structure•Extremely fine TiAlN crystals were formed•The atomic mixing or the bond energy lead to the change of lattice spacing•TiAlN nc grains are separated by a matrix phase