A5029911679- Metal and Thin Film Mechanics
- Boron and Carbon Nanomaterials Research
- MXene and MAX Phase Materials
- Advanced materials and composites
- Advanced ceramic materials synthesis
- Diamond and Carbon-based Materials Research
- Semiconductor materials and devices
- Machine Learning in Materials Science
- Intermetallics and Advanced Alloy Properties
- Microstructure and mechanical properties
- Metallurgical and Alloy Processes
- GaN-based semiconductor devices and materials
- Advanced Materials Characterization Techniques
- ZnO doping and properties
- Adhesion, Friction, and Surface Interactions
- Metallic Glasses and Amorphous Alloys
- Material Properties and Applications
- High Temperature Alloys and Creep
- High Entropy Alloys Studies
- High-Temperature Coating Behaviors
- Inorganic Chemistry and Materials
- Thermal and Kinetic Analysis
- Surface Roughness and Optical Measurements
- Aluminum Alloys Composites Properties
- Tunneling and Rock Mechanics
TU Wien
2016-2024
Linköping University
2022-2024
Masaryk University
2016-2019
Czech Academy of Sciences
2018
Montanuniversität Leoben
2017
Transition metal nitride thin films traditionally possess a low intrinsic fracture toughness. Motivated by the recently discovered toughness enhancing superlattice (SL) effect, as well remarkably high potential for predicted theoretical studies TiN/WN superlattices, we synthesise series of these materials DC reactive magnetron sputtering. The SL coatings demonstrate vacancy-stabilised cubic configuration throughout, marginal lattice mismatch between TiN and WN layers. All investigated...
Interfaces between components of a material govern its mechanical strength and fracture resistance. While great number interfaces is present in nanolayered materials, such as superlattices, their fundamental role during loading lacks understanding. Here we combine ab initio classical molecular dynamics simulations, nanoindentation, transmission electron microscopy to reveal atomistic mechanisms underlying plasticity crack growth B1 AlN(001)/TiN(001) superlattices under loading. The system...
Based on a combined computational and experimental study, we show that besides the thermodynamically stable β-MoN0.5 δ2-MoN phases, also metastable γ-MoNx its ordered relative γ′-MoNx can be synthesized by physical vapor deposition. The formation of NaCl-based phase is favored for nitrogen concentrations between 23 34 at.% (i.e., x = 0.30–0.53). Higher contents (close to 3:2 stoichiometry, hence, MoN0.67) favor ordering vacancies at sublattice (hence, γ′-MoNx). highest hardness ∼33 GPa...
Motivated by density functional theory (DFT)-derived ductility indicators for face centered cubic (fcc, rocksalt) structured TiN/MoN0.5 superlattices and Ti0.5Mo0.5N0.75 solid solutions, TiN/MoNy superlattice (SL) thin films with bilayer periods Λ of 2.4, 3.9, 6.6, 9.9, 23.0 nm corresponding solutions were developed DC reactive magnetron sputtering. These SLs allow improved hardness H critical fracture toughness KIC, both peaking at the same period 9.9 (where MoN0.5 layers crystallize...
Abstract Machining and forming tools exposed to challenging environments require protective coatings extend their lifetime reliability. Although transition metal nitrides possess excellent strength resistance against chemical attacks, they lack ductility are prone premature failure. Here, by investigating structural mechanical properties of MoN-TaN superlattices with different bilayer thickness, we develop high fracture toughness hardness, stemming from the formation a metastable...
Defects significantly affect the mechanical properties of materials. However, quantitatively correlating point defects with property could be a challenge. In this study, we explore defect effects on structure and magnetron sputtered TiN nanocrystalline films (synthesized using different negative bias potential) via combination analytical techniques density functional theory (DFT) calculations. We gain insights into structural evolution at length scales. It is found that nanocrystal...
Face-centered cubic transition metal carbides exhibit high melting points and hardness, making them prominent candidates for protective coating applications. Vanadium carbide (VC) has typical characteristics of carbides. It serves as model material in this study, which we showcase the effect superlattice architecture on mechanical properties fracture toughness. While beneficial effects arrangement have been demonstrated a series nitride-based coatings, remain largely unexplored territory....
We employ \textit{ab initio} calculations to investigate energetics of point defects in metastable rocksalt cubic Ta-N and Mo-N. Our results reveal a strong tendency off-stoichiometry, i.e. defected structures are predicted be more stable than perfect ones with 1:1 metal-to-nitrogen stoichiometry, agreement previous literature reports. While significantly favours metal vacancies, Mo-N exhibits similar energies formation regardless the vacancy type ($V_\text{Mo}$, $V_\text{N}$) as long their...
Superlattices—alternating coherently grown materials of nm thicknesses—proved their potential for enhancing typically antagonistic properties ceramics: ductility, hardness, and fracture toughness. Material selection, however, is far from trivial, as superlattice films do not simply combine mechanical layer components. Here we employ high-throughput density functional theory calculations to develop design guidelines nanolaminates combining cubic transition metal nitride and/or carbide...
The low intrinsic fracture toughness of transition metal nitride thin films critically restrains their applicability as protective coatings. We therefore investigate the Ti1-xWxNy system to provide detailed theoretical and experimental insight into simultaneous hardening toughening effects induced by heavy-element-alloying via an enhanced metallic bonding character. combination structural chemical analyses – supported density functional theory (DFT) calculations demonstrates that addition W...
The Ti–B–N system offers a wide range of possible meta(stable) phases, making it interesting for science and industry. However, the solubility B within face-centered cubic (fcc)-TiN lattice is rather limited less studied, especially without forming B-rich phases. Therefore, we address how chemistries along TiN–TiB2 or TiN–TiB tie-line influence this B-solubility. variation between these two tie-lines realized through non-reactive co-sputtering TiN, TiB2, Ti target. We show that variations...
Despite growing environmental concern, combustion engines are projected to stay the main technology of transportation for many years, so will unpopular S- and P- containing additives in lubricating oils. Therefore, it is essential maximize efficiency minimize harmful impacts these meantime. Coatings based on Mo W hold great promise as they can chemically interact with S-bearing form low friction tribofilms like MoS2 particular WS2. Here we highlight reaction pathways involving first...
Transition metal carbides belong to ultra-high temperature ceramics and are particularly valued for their high thermal mechanical stability as well melting points of even above 4000 °C. However, a considerable limitation these materials is inherent brittleness. Inspired by the success nanolayered superlattice architecture—shown enhance both hardness toughness transition (TM) nitrides—we developed films with TM carbides. Among these, density functional theory calculations suggest TaC/HfC...
Tailoring vacancies is a feasible way to improve the mechanical properties of ceramics. However, high concentrations usually compromise strength (or hardness). We show that elasticity and flexural could be achieved simultaneously using nitride superlattice architecture with disordered anion up 50%. Enhanced primarily result from distinctive deformation mechanism in ceramics, i.e., unit-cell disturbances. Such disturbance substantially relieves local high-stress concentration, thus enhancing...
Transition metal nitrides are widely used in the hard materials and protective coatings industry, but limited by their low fracture toughness. Encouraged previous studies on remarkable simultaneous improvements strength ductility through superlattice (SL) architectures, various TiN/MoN SL thin films were developed MgO (100) substrates. By varying bilayer periods (Λ) between 2 23 nm with ratios (Γ = ℓ MoN : TiN ) of 0.5, 1, 2, 2.7, individual effects structure mechanical properties can be...