Regensburg 2019 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 5: Mechanical Properties
MM 5.3: Talk
Monday, April 1, 2019, 10:45–11:00, H46
Mechanical properties of CrN-based nitride superlattices from ab inito calculations — •Lukas Löfler1, Paul Heinz Mayerhofer2, Matthias Bartosik2, and David Holec1 — 1Montanuniversität Leoben, Leoben, Austria — 2TU Wien, Vienna, Austria
Thin film coatings are used to protect surfaces of tools and components from harsh environmental and/or though pplication conditions. Next to changing the composition, a new way to tune material properties is to carefully create a microstructural design for the material. The simplest way are (semi-) coherent multilayers with a bi-layer period in the nm range. At certain thicknesses the materials show a significant increase in hardness and fracture toughness, two material properties relevant for many applications.
At such small scales the interface has an increasing influence on the overallproperties of the material. Density Functional Theory (DFT) is a potent technique to describe these superlattices and investigate their mechanical properties. CrN, a common coating material, was paired with AlN and TiN to form superlattices. At first, the elastic constants of different interface orientations were determined. Further, the critical tensile strength at and near those interfaces were calculated. To correlate the results to experiments, the KIC values in and perpendicular to the interface directions were calculated.