NDT and Materials Characterization

- Tasks / Main focus
- Special facilities
- Contact person

Department 53 NDT and Materials Characterization is subdivided into the following Units:

  • Unit 531  Non-destructive Testing
  • Unit 532  Electron Microscopy and Metallography
  • Unit 533  Research Network AMICA

Material properties and imperfections are a major influencing factor for the behavior of components under operational loads and for the lifetime of components and installations. Characterization and imaging of material properties on multiple length scales is an essential tool in studies of material behavior under the expected loads and of damage mechanism and progression. The Department NDT and Materials Characterization with its equipment and expertise can study and characterize different material properties down to the nm-scale range. The knowledge gained through characterization and imaging can be applied to optimize material properties and fabrication processes, and will contribute to the identification of causes for component failures.

Detection and characterization of macroscopic flaws with non-destructive inspections methods takes a pivotal role for safe and reliable operation of components and structures. Pre-service inspections will ensure the necessary fabrication quality of components; regular in-service inspections allow early detection and monitoring of flaws, which helps prevent unexpected failure of components. NDT will provide the necessary input parameters for the assessment of the condition and residual lifetime of components.

The department’s laboratories are accredited according to DIN EN ISO/IEC 17025:2005 for different NDT methods, metallography, and electron microscopy. The department also holds accreditation according to DIN EN ISO/IEC 17020:2012 as inspection body type A for determination of conformity with requirements of the High Pressure Gas Pipeline Ordinance (Gashochdruckleitungsverordnung - GasHDrLtgV). 

Schadensuntersuchung an einer Kurbelwelle
Analysis of a fractured crankshaft
 Tasks / Main focus
Research / Development
  • Study of materials microstructure and its relation to material behavior under loads (thermal, mechanical)
  • Determination and characterization of features related to damage mechanisms, such as optical microscopy for visualization of creep cavities or study of the evolution of precipitates using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) imaging
  • Novel sample preparation techniques for metallography and electron microscopy
  • Scientific and technical studies and projects related to:
        -  Application of ECCI technique within the field-emission-SEM AURIGA
           for determination of dislocation densities
        -  Thermodynamic simulation of phases and precipitates in high-temperature creep-resistant steels
        -  Evaluation of the impact of microstructural properties on hardness and deformation resistance
           in nickel alloys for power plant applications
  • Studies on ultrasonic inspection of austenitic stainless steel welds, nickel alloy welds, and dissimilar metal welds
  • Evaluation of uncertainties in non-destructive testing for probabilistic reliability assessment of components
  • Transfer of scientific research results into on-site applications for safe and reliable operation of components and installations
  • Stuttgart Research Focus (SRF) Advanced Materials Innovation and Characterization AMICA:
        -  Initiation of a shared experimental and numerical infrastructure for multi-scale materials characterization
           of modern materials
        -  Linking of experiments and simulation on multiple scales
        -  Generation of comprehensive information to determine material properties and component behavior
        -  Transfer of basic research into application-relevant developments and services in the field
           of material characterization
        -  Better exchange of knowledge and use of synergies through interdisciplinary cooperation between
           materials science, biology, physics, and engineering
        -  Interdisciplinary development and implementation of ideas
        -  Accelerated development of materials and methods

Eindringprüfung interkristalline Spannungsrisskorrosion

Ultraschallprüfung: Abbildung interkristalliner Spannungskorossionsrisse in Austenit

Dye penetrant testing of inter-granular stress corrosion crack in austenitic stainless steal
Ultrasonic inspection: Imaging of stress corrosion crack in austenitic stainless steel
Testing / Determining
  • Microstructure characterization using optical and scanning electron microscopy, including quantitative evaluation with automated image analysis techniques
  • Hardness testing
  • Determination of the chemical composition of steels and aluminum alloys (spectral analysis)
  • Imaging of surfaces and characterization of fracture surfaces and cracks using scanning electron microscopy (SEM)
  • Transmission electron microscopy (TEM) for high-resolution microstructural imaging, analysis of crystallographic phases, and determination of local chemical composition on a nanometer-scale
  • Thermodynamic simulation for determination of phase diagrams and precipitation processes
  • Non-destructive testing of parts, components, welds, etc. using

     Ultrasonic testing (UT):
        -  Conventional and Phased Array
        -  Manual and semi-automated scanning (lab and on site), fully mechanized laboratory scanner
        -  manuelle Prüfung im Labor und vor Ort, mechanisierte Prüfung im Labor
        -  Wall thickness measurements

          Radiographic testing ):
             -  Imaging of internal structures in parts and components
             -  X-ray film or digital radiography

          Surface inspection with magnetic particle testing (MT) or penetrant testing (PT):
             -  Fast, high-sensitivity methods for detection of surface defects (in the lab and on site

          Eddy current testing (ET):
             -  Detection of defects near the surface of conducting materials
             -  Detection of differences in conductivity and/or permeability
             -  Thickness of layers and coatings

          Visual inspection (VT):
             -  Inspection of surface, evaluation of surface quality, detection of surface defects
             -  Inner surface inspection using borescopes

          Acoustic emission testing (AT):
             -  Monitoring of crack initiation and damage progression

Konstruktur-Ätzung an  Kornstruktur-Ätzung an Ultraschall Untersuchung elektronischer Komponenten mittels digitaler Radiografie (Speicherfolientechnik)
Etched macrograph – visualization of grain structure in an austenitic weld and stress corrosion crack in the heat affected zone
Radiographic imaging of electronic components
Applications / Analyses
  • Characterization of material condition and material properties, including flaws, for metals and non-metals
  • Study and quantitative analysis of load-induced microstructural changes in metals and compound materials; correlation of microstructural features with material and component behavior
  • Improving reliability of non-destructive inspection and evaluation of components and installations during fabrication and operation
  • Development of procedures for performance demonstration of non-destructive testing methods and techniques
  • Characterization of crack initiation, damage progression, and crack growth during material and component tests using acoustic emission testing and ultrasonic testing
  • Testing of individual parts in small or medium quantities in the lab
  • Determination of input parameters for lifetime assessment of specific components
Aluminiumlegierung: Übersicht über eine Kehlnaht; Barker-Ätzung Freigeschnittener Bereich für Tomographie, FIB-Präparation
Aluminum alloy weld - Barker’s etching
FIB: preparation for tomography
Isolationsschicht für Hochtemperatur-Brennstoffzelle, thermisch gespritzte Schichten (VPS) Isolationsschicht für Hochtemperatur-Brennstoffzelle, thermisch gespritzte Schichten (VPS) Isolationsschicht für Hochtemperatur-Brennstoffzelle, thermisch gespritzte Schichten (VPS)
  • 3D imaging of selected phases in an insulating layer for high-temperature fuel cells – deposited by thermal spraying (vacuum plasma spraying VPS)
Assessment / Consulting / Inspection
  • On-site in-service inspections of power plant components (hydroelectric, fossil-fired)
  • Independent third-party inspections and evaluations (execution of NDT / NDT results)
  • Development of solutions/ adaptations for particular inspection tasks
  • Inspections for determination of conformity of high-pressure gas pipes
  • Evaluation of defects in high-pressure gas pipes 
Cooperation in Committees
  • VDEh Arbeitskreis Elektronenmikroskopie
  • VGB Werkstoffausschuss Werkstoffe und Qualitätssicherung
  • DGM Ausschuss Rasterelektronenmikroskopie
  • DGM Arbeitskreis Probenpräparation und Bauteilmetallographie
  • Arbeitskreise innerhalb der Arbeitsgemeinschaft Warmfeste Stähle und Hochtemperaturwerkstoffe (AGW)
  • Fachausschüsse der Deutschen Gesellschaft für zerstörungsfreie Prüfung (DGZfP): Ultraschallprüfung, Schallemission, Durchstrahlungsprüfung, Strahlenschutz
  • Ad-hoc Arbeitskreis ZfP des Kerntechnischen Ausschuss (KTA)
  • Ausschuss „Druckführende Komponenten und Werkstoffe“ (DKW) der Reaktorsicherheitskommission (RSK)
  • Programmausschüsse für Fachtagungen, z.B. WCNDT 2016, ASME PVP 2017
Elementmapping im Bereich einer Korngrenze im austenitischen Stahl HR3C Linescan der Elemente Cr, Fe und Ni
TEM: element mapping across a grain boundary in austenitic steel HR3C
Line scan across the grain boundary:
Cr (red), Fe (blue), Ni (green)
  • Undergraduate and graduate theses
  • Lab classes and lectures for the Institute for Materials Testing, Materials Science and Strength of Materials (IMWF)
  • Certificates of accreditaion
 Special facilities
  • Sample preparation equipment for metallography and optical microscopy: Vibration polishing (VibroMet2), fully automatic electrolytic polishing and etching (LectroPol5), fully automatic hardness testing (KB10) with a range of  HV 0.0025 – HV10
  • Optical Emission Spectroscopy (OES) for determination of the chemical composition of steels and aluminum alloys
  • Energy-dispersive X-ray micro analysis EDX (in combination with SEM und TEM)
  • Scanning electron microscope JEOL JSM 6400
  • Zeiss Auriga Crossbeam electron and ion beam microscope with EBSD system, Focused Ion Beam (FIB), lift-out technique, STEM, energy-dispersive X-ray micro analysis EDX
  • System for digital imaging, archiving and documentation (Imagic)
  • Transmission electron microscope Jeol JEM 2000FX
  • Transmission electron microscope Jeol JEM 2010 F
  • Software packages Thermocalc® und DICTRA® for calculation of phase diagrams and precipitation processes (thermodynamic simulation)
  • Quantitative microstructure image analysis
  • Ultrasonic system  GE USN 60 for use with conventional UT probes
  • Olympus Omniscan MX2 for use with conventional and  Phased Array probes
  • Ultrasonic simulation software package CIVA
  • Two-axes scanner for automated scanning and position-encoded data collection
  • Encoders for semi-automated scanning
  • Ultrasonic wall thickness measurement GE DMS 2 TC
  • Acoustic emission system Vallen AMSY6 for acquisition with up to 12 channels
  • X-ray tubes for radiography with energies up to 300 keV
  • Radiographic imaging using conventional X-ray film or high-resolution phosphor imaging plates (Dürr-NDT)
  • Videoscope Olympus IPLEX FX
  • Equipment for magnetic particle testing and penetrant testing in the lab and on site
  • Multi-frequency eddy current system for inspection with up to 4 frequencies, different probes, scanner for position-encoded data acquisition (lab device)
Gamma-Strich-Phase in einer Nickelgusslegierung, freigelegte Bruchfläche Gamma-Strich-Phase in einer Nickelgusslegierung, Ätzung: 10% Oxalsäure
Gamma-prime phase in a cast nickel alloy (SEM image of the fracture surface)
SEM image of gamma-prime phase in a cast nickel alloy; etched with 10% oxalic acid
Further Information
 Contact person


Mrs. I. Groth

Mrs. B. Stopper

 ++49 (0)711/685-60724
  ++49 (0)711/685-65766

Head of Department




Mrs. Dr.-Ing. M. Speicher

 ++49 (0)711/685-60334


Non-destructive Testing

Mrs. Dr.-Ing. A. Jüngert

Mr. Dipl.-Ing. H.-J. Gertkemper

 ++49 (0)711/685-66787

 ++49 (0)711/685-62554

Electron Microscopy and

Mrs. Dr.-Ing. M. Speicher

Mr. Dr. rer. nat. F. Kauffmann

 ++49 (0)711/685-60334

 ++49 (0)711/685-62545

Research Network AMICA

Mrs. Dr. rer. nat. M.-L. Lemloh

 ++49 (0)711/685-60818