Title:	Temperature-dependent properties of transition metal nitrides and carbides via equilibrium and non-equilibrium quantum molecular dynamics
DNr:	SNIC 2017/1-459
Project Type:	SNIC Medium Compute
Principal Investigator:	Valeriu Chirita <vio@ifm.liu.se>
Affiliation:	Linköpings universitet
Duration:	2017-11-01 – 2018-11-01
Classification:	20501
Keywords:

Abstract

We use density-functional-based ab initio molecular dynamics (AIMD) to determine the electronic and mechanical properties of transition metal nitrides and carbides as a function of temperature. Given the limitations on the time-scales accessible via highly computationally-demanding AIMD simulations, a non-equilibrium technique (accelerated AIMD) that we have recently developed is employed to efficiently achieve accurate quantitative evaluation of the rate of rare events, such as dislocation glide and point-defect formation and migration. We are currently modelling crack formation, dislocation glide, nanoindentation and compression of nanopillars for transition metal nitride and carbide systems via AIMD. Using the resources provided by SNIC, during 2016 and 2017 we have published 12 papers in peer-reviewed journals and one Master Thesis (Dr. D. Edström) which is entirely based on results collected using SNIC resources. SNIC resources have been employed for all these projects and acknowledged in all publications. Other four manuscripts are currently under review in Physical Review B, Physical Review Materials, Acta Materialia, and New Journal of Physics. 1. Sangiovanni, Hultman, Chirita Effects of phase stability, lattice ordering, and electron density on plastic deformation in cubic TiWN pseudobinary transition-metal nitride alloys Acta Materialia 103, 823 (2016) 2. Sangiovanni, Tasnadi, Hultman, Petrov, Greene, Chirita N and Ti adatom dynamics on stoichiometric polar TiN(111) surfaces Surface Science 249, 72 (2016) 3. Sangiovanni, Hellman, Alling, Abrikosov Efficient and accurate determination of lattice-vacancy diffusion coefficients via non-equilibrium ab initio molecular dynamics Physical Review B 93, 094305 (2016) 4. Sangiovanni, Mei, Hultman, Chirita, Petrov, Greene Ab initio molecular dynamics simulations of nitrogen/VN(001) surface reactions: vacancy-catalyzed N2 dissociative chemisorption, N adatom migration, and N2 desorption The Journal of Physical Chemistry C 120, 12503 (2016) 5. Edström, Sangiovanni, Hultman, Petrov, Greene, Chirita Large-scale molecular dynamics simulations of TiN/TiN(001) epitaxial film growth Journal of Vacuum Science & Technology A 34, 041509 (2016) 6. Mei, Tuteja, Sangiovanni, et al. Growth, nanostructure, and optical properties of epitaxial VNx/MgO(001) (0.80 ≤ x ≤ 1.00) layers deposited by reactive magnetron sputtering Journal of Materials Chemistry C 4, 7924 (2016) 7. Mikula, Plašienka, Sangiovanni et al. Toughness enhancement in highly NbN-alloyed Ti-Al-N hard coatings Acta Materialia 121, 59 (2016) 8. Edström, Sangiovanni, Hultman, Petrov, Greene, Chirita Effects of incident N atom kinetic energy on TiN/TiN(001) film growth dynamics: A molecular dynamics investigation Journal of Applied Physics 121, 025302 (2017) 9. Mikula, Sangiovanni, et al. Thermally induced age hardening in tough Ta-Al-N coatings via spinodal decomposition Journal of Applied Physics 121, 155304 (2017) 10. Mikula, Truchlý, Sangiovanni, et al. Experimental and computational studies on toughness enhancement in Ti-Al-Ta-N quaternaries Journal of Vacuum Science & Technology A 35, 060602 (2017) 11. Gambino, Sangiovanni, Alling, Abrikosov Nonequilibrium ab initio molecular dynamics determination of Ti monovacancy migration rates in B1 TiN Physical Review B 96, 104306 (2017) 12. Edström, Sangiovanni, Hultman, Petrov, Greene, Chirita Elastic properties and plastic deformation of TiC- and VC-based pseudobinary alloys Acta Materialia (accepted)