In this paper we explore an apparent disagreement between the nominal stoichiometry and reported elemental composition of Nb3Al. By employing standard DFT phase stability assessment combined with evolutionary algorithms we were able to show that the phase can become mechanically and vibrationally stable when considering Nb anti-sites which additionally leads to experimentally reported composition.
N. Koutná, P. Erdely, S. Zöhrer, R. Franz, Y. Du, S. Liu, P.H. Mayrhofer, D. Holec: "Experimental Chemistry and Structural Stability of AlNb3 Enabled by Antisite Defects Formation". Materials, 12(7), 1104 (2019). DOI: 10.3390/ma12071104
In this paper we use ab initio calculations to study impact of crystal structure (cubic vs. hexagonal) and interface orientation (cubic (001) or (111)) on elastic properties and tensile strength of TiN/AlN superlattices. We were able to reproduce and explain experimental trends in bi-layer period dependence of Young's modulus.
N. Koutná, P. Řehák, Z. Chen, M. Bartosik, M. Fallmann, M. Černý, Z. Zhang, M. Friák, M. Šob, P.H. Mayrhofer, D. Holec: "Correlating structural and mechanical properties of AlN/TiN superlattice films". Scr. Mater., 165, 159–163 (2019). DOI: 10.1016/j.scriptamat.2019.02.021
A series of papers focusing on stability and mechanical properties of nanocomposites, strength of interfaces and grain boundaries, elasticity of grain boundaries and pressure impact on elastic anisotropy has been recently published. These are results of a long-standing collaboration between our group and the group of Dr. Friák and Prof. Šob at the Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Brno.
I. Miháliková, M. Friák, Y. Jirásková, D. Holec, N. Koutná, M. Šob: "Impact of Nano-Scale Distribution of Atoms on Electronic and Magnetic Properties of Phases in Fe-Al Nanocomposites: An Ab Initio Study". Nanomaterials (Basel), 8(12) (2018). DOI: 10.3390/nano8121059
M. Friák, D. Holec, M. Šob: "Quantum-Mechanical Study of Nanocomposites with Low and Ultra-Low Interface Energies". Nanomaterials (Basel), 8(12) (2018). DOI: 10.3390/nano8121057
M. Friák, P. Kroupa, D. Holec, M. Šob: "An Ab Initio Study of Pressure-Induced Reversal of Elastically Stiff and Soft Directions in YN and ScN and Its Effect in Nanocomposites Containing These Nitrides". Nanomaterials (Basel), 8(12) (2018). DOI: 10.3390/nano8121049
M. Friák, M. Zelený, M. Všianská, D. Holec, M. Šob: "An Ab Initio Study of Connections between Tensorial Elastic Properties and Chemical Bonds in Σ5(210) Grain Boundaries in Ni3Si". Materials, 11(11), 2263 (2018). DOI: 10.3390/ma11112263
P. Šesták, M. Friák, D. Holec, M. Všianská, M. Šob: "Strength and Brittleness of Interfaces in Fe-Al Superalloy Nanocomposites under Multiaxial Loading: An ab initio and Atomistic Study". Nanomaterials, 8(11) (2018). DOI: 10.3390/nano8110873
Dominik Nöger was selected among the 20 Master theses to be awarded "WKO Steiermark Forschungsstipendien 2018". The award ceremony took place in Europasaal of the WKO Steiermark in Graz on Monday December 10, 2018.
Congratulations!
Dominik has successfully defended his MSc thesis on "Interaction of the H2 molecule with carbon nanostructures: A DFT study" and has passed the final exam to get an MSc degree in Materials Science.
Congratulations!
After about a year of promises and discussions, the very first stub of our group website comes on-line. It is by far not complete nor in a final shape, but it is alive!
A new paper on an initio molecular dynamics study of early stages of oxidation of Ti-Al-N coatings has been accepted in Applied Surface Science. We report on impact of temperature and Al content on the structure of the oxide layer and show, that the composition strongly influences whether an Al-rich or a Ti-rich layer builds near to the interface coating-oxide.
F. Guo, J. Wang, Y. Du, D. Holec, P. Ou, H. Zhou, L. Chen, Y. Kong: "Structural evolution of oxygen on the surface of TiAlN: Ab initio molecular dynamics simulations". Appl. Surf. Sci., 470, 520–525 (2019). DOI: 10.1016/j.apsusc.2018.11.158