Elastic properties and plastic deformation of TiC- and VC-based pseudobinary alloys. (1st February 2018)

• Record Type: Journal Article
• Authors: Edström, D.; Sangiovanni, D.G.; Hultman, L.; Petrov, Ivan; Greene, J.E.; Chirita, V.
• Is Part Of: Acta materialia. Volume 144(2018)
• Page Start: 376
• Page End: 385
• Publication Date: 2018-02-01
• Subjects: Carbides -- Density functional theory -- Elastic properties -- Ductility -- Toughness; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2017.10.047
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: Transition-metal (TM) carbides are an important class of hard, protective coating materials; however, their brittleness often limits potential applications. We use density functional theory to investigate the possibility of improving ductility by forming pseudobinary cubic M 1 M 2 C alloys, for which M 1 = Ti or V and M 2 = W or Mo. The alloying elements are chosen based on previous results showing improved ductility of the corresponding pseudobinary nitride alloys with respect to their parent compounds. While commonly-used empirical criteria do not indicate enhanced ductility in the carbide alloys, calculated stress/strain curves along known slip systems, supported by electronic structure analyses, indicate ductile behavior for VMoC. As VMoC layers are sheared along the 1 1 ¯ 0 direction on {111} planes, the stress initially increases linearly up to a yield point where the accumulated stress is partially dissipated. With further increase in strain, the stress increases again until fracture occurs. A similar mechanical behavior is observed for the corresponding TM nitride VMoN, known to be a ductile ceramic material [1]. Thus, our results show that VMoC is a TM carbide alloy which may be both hard and ductile, i.e. tough. Graphical abstract: Image 1