From quantum mechanics to material behavior

Materials Modeling

We investigate material behaviors and predict material properties using theoretical and computational methods based on solid-state physics and materials mechanics. Our ambition is to design material structures with targeted properties and functions. We identify the effects of crystalline defects and microstructures on the material behavior, and we explore means to avoid negative or exploit positive effects.

Services

Using simulator-based methods based on theoretical solid-state physics and materials mechanics, we can resolve material behavior and predict material properties.

 

We:

offer you pragmatic access to the diverse possibilities of atomic materials modeling by means of customized solutions.

investigate and evaluate, in physical terms, new types of materials and check their potentials in regard to the required property profile.

reduce trial-and-error loops by searching the large scope of possibilities of materials development and optimization quickly and efficiently.

develop model systems for materials in their complex application or manufacturing context and reduce them to the decisive factors. In this way we offer pathbreaking decision-making tools for materials design and materials optimization.

 

The value of our simulation calculations can be realized from the insights and explanations of the internal mechanisms of materials and to cause-and-effect relationships.

 

We resolve the correlation between the physical properties of a material on the one hand and its atomic and electronic structures on the other. We provide understanding of the underlying mechanisms and relationships, and this enables you to optimize the starting materials of your products and thus to adapt them to specific operating conditions and requirements:
 

Structural properties such as atomic crystal structure and chemical composition

Thermodynamic properties such as energy of formation and phase stability

Mechanical properties such as elastic constants and mechanical tensions

Electrical properties such as electrical conductivity, band structure and dielectric constants

Piezoelectricity

Magnetic properties such as magnetization and anisotrophy

Optical properties such as transparency and reflectivity

Thermal properties such as the coefficient of thermal expansion

Kinetic properties such as energy barriers for nuclear diffusion processes

Topics

 

Optically transparent and electrically conducting oxides (TCOs)


Touchscreens are now a common feature of smartphones, tablets or ticket machines. An important component in these screens is the oxide layer that is both transparent and conducting. TCOs (transparent conducting oxides) are also used as solar cell contacts and in heated windows. The IWM provides support for the development and optimization of TCOs in the form of atomic-scale simulations. This makes it possible ...

 

 

 

Ferroelectrical ceramics for piezo applications

 

Ferroelectric materials are used to manufacture precision mechanical actuators and sensors. Lead zirconia titanate (PZT) is one of the best materials for the job because of its excellent electromechanical properties. Potassium sodium niobate (KNN) is a promising lead-free alternative to PZT. The effects of atomic defects, domain walls and grain boundaries, which play a role during industrial manufacturing processes, are investigated using density functional...

 

 

Ceramic reliability and life expectancy

 

The reliability and life expectancy of ceramic components can be increased by optimizing the microstructure of the material. Multi-scale simulations are used to determine the relationship between the crystal structure, microstructure and macroscopic properties. This makes it possible to better validate constitutive material laws, and parameterize and reliably predict crack formation and propagation under high thermal and mechanical loads...

 

 

 

New hard magnets free of rare earth metals

 

Hard magnets play a crucial role in converting electromechanical energy in electromobility applications and wind turbines. The increased demand for materials containing rare earth metals has, however, reached a critical level. In the search for material substitutes that are free of rare earth metals, ab initio density functional theory is used to calculate magnetic parameters for real and hypothetical crystal phases...

 

 

 

NZP materials as solid-state electrolytes for lithium ion batteries

 

When used as electrode materials for lithium ion batteries, ion-conducting solid-state bodies can significantly improve operational safety. The three dimensional canal network in the crystal structure of materials derived from NaZr2(PO4)3 (NZP) is a strong conductor of ions. Density functional theory and atomistic simulations are used to investigate Li-ion diffusion in relation to the NZP composition and Li stoichiometry in...

 

 

 

Hydrogen in iron and steel

 

Hydrogen penetration into metals causes their mechanical stability to degrade – a phenomenon known as hydrogen embrittlement. Hydrogen embrittlement affects almost all metals and is therefore the cause of significant technical and economic damage. The IWM investigates the inclusion and migration of hydrogen atoms in iron and nickel using quantum mechanics and atomistic computer simulations. The susceptibility of the metals to hydrogen embrittlement can be concluded from...

 

 

Precipitation in iron and steel

 

The efficiency of conventional power stations can be increased through the use of new heat and corrosion resistant steels that are able to withstand higher temperatures and steam pressures. Steels with a high chrome content are made more resistant to fracture and creep by aiming for a microstructural design with Z phase precipitation. At the IWM, we investigate the formation of these nitrides using a multi-scale approach that combines atomistic simulations and thermodynamic modeling...

 

 

 

Publications regarding Materials Modeling


Contributions to newspapers, books and conferences as well as dissertations and project reports...

The fields of application in which our expertise of physical materials modeling can make a significant contribution are:

Development and use of complex functional materials.

Products in which material combinations and the interaction of materials decide the function.

Functional components for where the most extreme demands are made regarding the reliability and function of materials and components and on error rates in production.

Development and improvement of materials where trial-and-error loops are uneconomic and do not lead to a solution, and where a fundamental understanding of the problem is required.

For example in lighting technology, in steel or ceramics manufacture, in photovoltaics or in electromagnetic generators and motors, in energy storage and energy conversion systems.

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Topics for Collaboration

Unwanted or unintended changes in the properties or function of the material manufactured or used (e.g. failure or breakdown of protective layers, interface reactions in layer sequences, the formation of mixed phases)

 

We investigate the causes of failure in materials due to microstructural changes. This allows the manufacturing process to be designed such that the optimum microstructure is obtained and the strength and working life of the material is improved. Separations and structural defects in iron and steel.

Prediction of the influence of additives on functional properties. Ferro-electric ceramic materials for piezo applications.

Understanding of the optical and electronic properties of semiconductor materials through band-structure engineering. Optically transparent, electronically conductive oxides.

Improvement to materials (e.g. protection against corrosion and damage from hydrogen)

 

We investigate and model diffusion processes for an understanding of corrosion and embrittlement. The knowledge gained is used to develop effective protective layers and to achieve an extended material service life. Hydrogen in iron and steel.

New development of materials and substitution of materials (e.g. magnet, battery and piezo materials)

 

We investigate the behavior of individual atoms in your material-specific environment, such as lithium ions in battery substances, for example. NZP materials as a solid-state electrolyte for lithium-ion batteries.

We develop efficient, rapid methods of finding replacements for critical elements such as costly raw materials or additives that are harmful to health, or for reducing the amount of such elements that are in use. New hard magnets without rare earth metals.

Multiscale modeling for the virtual development of polycrystalline materials; reliability and long life of carbide, nitride and oxide ceramics.

Development of Materials Models for:

 

Deformation (elasticity, plasticity and breakage)

Damage (diffusion, reaction, corrosion)

Conductivity (electron conductivity, ion conductivity)

Piezoelectricity

Magnetism

Optical transparency

Impurities

Crystal defects

Separations

Functionality of metals, semiconductors and ceramics

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We define the scope of services required jointly with our clients

Calculation of Properties: We calculate the material properties of an existing system (system to be defined) in order to obtain a model representation of its functions (e.g. layer adhesion, plasticity, elasticity, phase stability)

 

Optimization Concepts: We simulate structure-to-property relationships and derive knowledge-based measures on how to move from the initial status to a target status. Under which conditions do which effects occur?

 

Development Projects: We develop new materials or material combinations together with our partners

 

The forms of collaboration are determined by the client’s needs and the demands of the task and range from consultation meetings, workshops and feasibility studies through to direct contract or consortium-based R&D projects.

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The process of a project

Step 1: Client Input: Description of Task

 

Materials used

Manufacturing process

Process conditions

The problem encountered

 

Step 2: Analytical Problem Diagnosis

 

Delimit the potential material mechanisms or phenomena

Formulate potential cause-effect relationships

Prioritize cause-effect relationships

Define necessary or additional experimental and theoretical investigations

Derive efficient strategies for solving the problem

 

Step 3: Check the Problem-Solving Strategy

 

Conduct experiments and simulations.

Examine cause-effect relationships on the basis of prototype parameter variations in the material development or in the manufacturing steps of the client.

Validate relationships of source materials and manufacturing steps with material properties and functions.

 

Step 4: Implementation of the Solution in the Company

University courses

Winter semester 2013/2014 and summer semester 2014
Theoretical Models for Magnetic Solids
Prof. Dr. Christian Elsässer, Faculty for Mathematics and Physics, University of Freiburg

Winter semester 2012/2013 and summer semester 2013
Electronic Structure of Condensed Matter I + II
Prof. Dr. Christian Elsässer, Faculty for Mathematics and Physics, University of Freiburg

Winter semester 2011/2012 and summer semester 2012
Superconductivity I + II
Prof. Dr. Christian Elsässer, Faculty for Mathematics and Physics, University of Freiburg

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