Identification of interrelated microstructural properties

Microstructure and Residual Stresses

We investigate the effect of manufacturing processes and operational loads on the microstructure and the internal stress in materials and components. A particular focus lies on the identification of the combinatory degradation mechanisms of high temperature corrosion, stress corrosion cracking and hydrogen embrittlement. This is done using experimental methods, such as permeation tests with superimposed mechanical loads, and numerical methods, such as the simulation of microstructure and internal stress formation. This lays the groundwork for the correct selection of materials or the optimization of materials and processes and the prediction of operational behavior.

What we offer


  • Analysis and assessment of material microstructures in relation to the manufacturing process and operating conditions
  • Simulation, experimental identification and assessment of residual stresses
  • Investigations of material degradation due to corrosion, stress corrosion cracking, high temperature corrosion and hydrogen embrittlement
  • Thermodynamic simulation of microstructural formation
  • Identification of interrelated microstructural properties
  • Damage analysis, identification of technical liability, surveys carried out through publically appointed and impartial experts




Microstructure assessment

Microstructures are responsible for the properties of raw materials and therefore for the properties of the resulting components which are produced. Microstructures are adjusted using different manufacturing steps. In use, they can change both positively and negatively. We uncover the relationships between the raw materials’ properties and those of the microstructure and use this information for optimized raw material properties and for the optimized use of raw materials - for example with regard to mechanical properties, long-term behavior, life expectancy, abrasive properties, corrosion properties, etc.). By using computer simulations, we can predict microstructures and assess them with regard to the reliability, safety and expected lifetime of components. Building on this, we develop concepts to design components and optimize manufacturing.



Residual stress analyses

Our aim is to create residual stress optimized components for our clients.
To do so, we determine manufacturing and use-caused residual stresses, assess them with regard to the reliability, safety and lifetime of parts and develop recommendations and concepts for component design, raw material use and manufacturing processing.
In order to prepare requirements to use components safely and reliably, we investigate and analyze residual stresses in connection with the underlying raw material microstructure, environmentally-caused degradation....


Hydrogen embrittlement in metals

Atomic hydrogen is capable of significantly reducing the ductility of metals. This can cause components to fail unexpectedly. The potential risk is generally related to the diffusible portion of the hydrogen. In order to predict the effects of hydrogen on material and component behavior via numerical simulations, we determine the dependence of the hydrogen diffusion constants on mechanical stress and temperature. The effects of hydrogen on the mechanical parameters of a metal are...


Simulation of heat treatment processes

The heat treatment of metals is an important means of creating a favorable microstructure and residual stress within a component. A movable inductor is often used to heat up the components. The experimental optimization of the treatment parameters is time-consuming and costly, particularly for larger components such as wind turbine bearings. Thanks to our effective mapping techniques and an enhanced simulation environment, we are able to...


Relationship between microstructure and properties in re-melted surface

In many cases, the surface of a component is critical to operational behavior and can be modified in various ways. A new technique, laser re-melting of surface layers, finely polishes or adds structure to a surface. The mechanical properties in the surface layers are modified by adjusting the laser parameters. The effect of process parameters on residual stresses, hardness and carbon content was investigated...


Characterization and simulation of precipitation development in copper alloys

Precipitation particle size and distribution have a decisive influence on the subsequent mechanical properties of high-strength and highly conductive precipitation hardened copper alloys. The precipitation particle size for a specific Cu-Ni-Si alloy was investigated for various rolling and annealing processes. The data is entered into a thermodynamic-kinetic model that is capable of calculating the development of particle size in...


Solarthermal power plants: degradation of materials in molten salts

The long-term use of renewable, fluctuating energy sources requires the development of assessment and qualification concepts for materials in the high-temperature reservoirs of solar power plants based on molten salt (TES - thermal energy storage, CSP - concentrated solar power plants). Molten salt is used in many branches of industry, for example as baths made of molten chloride-salt mixtures for surface alloys or as fluoride salts to clean metal surfaces. In the meantime, molten salt from nitrates and nitrites have become more important as they are attractive heat conductivity and storage media for applications in energy generation.


Improvement of the surface layer strenght via shot peening


Shot peening is a widely used surface treatment to improve the static and cyclical strength of metal components. It is utilized in the mechanical stabilization of edge layers and for incorporation of more advantageous residual stresses. In close cooperation with industrial partners, we determine the optimum shot peening parameters in feasibility studies and measure depth-dependent residual stress profiles in our stress measuring laboratories in relation to beam parameters. We also determine the hardness, fracture toughness and static and cyclic load bearing capacity of the surface layer. We analyze surface properties such as coverage ratio, roughness and micro-cracking with other technical measurement methods. Fundamental investigations regarding the straightening of components by means of shot peening and shot blasting are also integral elements of our area of ​​expertise.


Damage analysis: metals


We answer questions that occur during the quality assurance phase of industrial production or due to failure during service. The scientific investigation of damage to and failures of metals and metallic components is well established within the Fraunhofer IWM. We will build an expert project team customized for your individual task, which will assess the situation and discuss the next steps with you to reach an effective solution.


Welded Joints: Assessment and Lifetime Concepts

We develop solutions which enable you to improve welding processes in your applications. Additionally, we support you in evaluating welded joints: was the welding done correctly? Did any cavities, pores or welding mistakes occur and/or was the welding incomplete? Did you create unwanted residual stress?...

Microstructure, Residual Stresses publications


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