Microstructure analysis
The development of materials requires knowledge about alloy composition, manufacturing parameters, microstructure and material properties. We have state-of-the-art equipment just for this and decades of experience.
Light microscopy/metallography
From the analysis of specimens, we draw conclusions about true strains or heat treatments, thereby optimizing the production processes, among other things. We have extensive experience with the material groups steel and cast iron as well as non-ferrous metals and alloys.
We use metallographic methods to collect the following information on the material to be analyzed:
- Microstructure composition (qualitative and quantitative)
- Type, distribution and frequency of precipitates
- Content of non-metallic inclusions (ISO 4967, DIN 50602, ASTM E45, DIN EN 10247)
- Grain size (DIN EN ISO 643, ASTM E112)
- Cracking and fracture behaviors
- Weld quality
- Micro- and/or nano-hardness
Knowledge about the microstructure and homogeneity of a material are key elements in the evaluation of material properties and of the manufacturing processes used, and in the investigation of damage claims.
Scanning electron microscopy (SEM)
Modern material development relies on the ability to characterize the microstructure and its various constituents as precisely as possible, in order to be able to establish correlations with material properties and process parameters. Moreover, the study of fracture surfaces and the local chemical analysis of inclusions, precipitates or crack areas play a decisive role in the understanding of material properties.
Our high-resolution field emission scanning electron microscopes (JEOL JSM 7001F, Zeiss Supra 55VP, TESCAN MIRA3) provide us with comprehensive microstructural analysis capabilities:
- Characterization of surface structures and fracture surfaces with high depth of field and resolution down to the nano range
- Analysis of grain shape and size, precipitates and inclusions
- Determination of crystallographic orientations through electron backscatter diffraction (EBSD) across a defined measurement grid on the specimen
- Measurement of element distribution (also of light elements such as carbon, nitrogen and oxygen) with EDS (energy dispersive X-ray spectroscopy)
Electron probe micro analysis (EPMA)
Wavelength-dispersive X-ray spectroscopy (WDS) on the electron microprobe (EMP) enables us to determine the chemical composition of a specimen with very high precision and spatial resolution. Particularly revelatory elements here include changes in concentration near critical microstructural constituents such as precipitates, segregations, non-metallic inclusions or cracks.
Our microprobes are specially equipped for the qualitative and quantitative measurement of element distribution.
X-ray diffractometry (XRD)
With XRD, we can analyze many questions relative to the structure and processing of materials:
- Analyze phases (qualitatively and quantitatively)
- Determine crystal orientations (textures)
- Identify crystal defects
- Study residual stresses
Instrumented hardness measurement
Analysis of local hardness inhomogeneities.
With a specified force, we continuously measure the penetration depth while a specimen is being loaded and unloaded. The force-penetration curve recorded can be used to determine the penetration hardness and the penetration modulus. The volume tested in the direct vicinity of the penetration here largely depends on the test force applied. By selecting the appropriate test force, it is possible to investigate local hardness inhomogeneities, e.g. due to microstructural differences or plastic deformation.
TTT diagrams
The microstructure and the properties of low-alloy steels largely depend on a component’s temperature-time history during production. Time-temperature transformation diagrams (TTT diagrams) are an important tool when it comes to analyzing the potential of a material with regard to its achievable microstructure.
Continuous time-temperature transformation diagrams are prepared on the basis of cooling curves recorded and analyzed by means of a dilatometer.