In-situ Characterization Facilities

Scanning Electron Microscope

TESCAN MIRA3 Scanning Electron Microscope

MIRA3 is a high-performance SEM system which features a high-brightness Schottky emitter for high-resolution and low-noise imaging. MIRA3 SEM equipped with a large GM chamber provides high compatibility with various type of in situ testing stages. In addition to high resolution SE and BSE imaging modes, the MIRA3 SEM has a special ‘Channeling’ mode which enables the acquisition of an image of the pseudo-Kikuchi lines (electron channeling pattern) from a crystalline materials using a BSE detector. In the special scanning mode, the electron beam is rocking around one point and creates a selected area channelling pattern (SACP).

Specifications:
  • Resolution: 1.2 nm at 30 keV / 2.5 nm at 3 keV
  • Available detectors:
    • Secondary electron (SE) detector
    • Backscattered-electron (BSE) detector with internal cooling
    • Low-energy backscattered-electron (LE-BSE) detector
    • In-beam SE/BSE detector
    • Energy dispersive spectrometer (EDS)
    • Electron-backscattered diffraction (EBSD) camera
  • Large GM Chamber for various in situ testing stages
    • Internal size: 340 mm(w) x 315 mm(d) x 320 mm(h)
    • Maximum specimen height: 106 mm with rotation stage (or 147 mm without)
    • 5-axis fully motorized stage with a large tilting capability of -80° ~ +90°
  • Electron Channeling Pattern Acquisition in Channeling mode

TESCAN Cooling Stage

TESCAN Peltier Cooling & Heating Stage

The Peltier stage allows for lowering the temperature of the sample by placing it on a temperature-controllable stage. The temperature of the stage is manipulated by creating a gradient of temperature between two dielectric plates which are separated by a semiconductor. A voltage is applied between the two electrodes connected to the semiconductor and a gradient in temperature is created. This phenomenon is known as the Peltier effect. The gradient can be reversed by switching the direction of the current. This method is excellent for small-scale heat extracting/transferring (cooling/heating) from a sample.

Specifications:
  • Temperature range: -50°C to +70°C
  • Temperature accuracy: ± 0.5°C
  • Temperature stability: ± 0.2°C
  • Maximum cooling speed: 30 °C per minute
  • Diameter of the specimen holder: 12.5 mm

Gatan Stage

Gatan_nobackground

Gatan MTEST2000 Uniaxial Testing Stage

In-situ tensile testing inside SEM allows dynamic microstructural observations and can provide new insights into materials research. A custom-designed sample clamp system enhances compatibility of the tensile stage with SEM-based intensive analysis techniques such as Electron Channeling Contrast Imaging (ECCI) and Electron Backscattered Diffraction (EBSD). In-situ analysis of bulk-to-microscale sample during deformation process provides a deeper understanding into deformation mechanisms of materials. Tensile, compression and bending tests are available. Cyclic tests under tensile or compression mode is also available. The in-situ capabilities of this stage was recently demonstrated in an micro-cracking study in metastable high entropy alloys.

Specifications:
  • Load cell options: 150 N and 2000 N
  • Distance between jaws: Min. 10 mm / Max. 10 mm
  • Displacement rate: 0.04 ~ 0.4 mm/min

Hysitron PI-88 Picoindenter

Hysitron PI-88 PicoIndenter

The Hysitron PI-88 SEM PicoIndenter is a comprehensive in-situ nanomechanical test instrument for SEM. The picoindenter provides an advanced instrument with powerful capabilities that delivers extraordinary performance and versatility. This picoindenter was used for micro-mechanical characterizations in our recent publications: in-situ hydrogen charging setup and fiber based artificial muscles.

Nanoindentation/compression test mode:

Precise lateral positioning and nanoscale load and depth control allow for the quantitative determination of fundamental mechanical properties such as hardness and elastic modulus for a wide variety of materials at a local area. Compression tests of micro-to-nanosized pillars, particles, and other small scale structures also can be performed by the picoindenter to measure stress-strain behavior and yield properties while observing deformation mechanisms in real time.

  • Interchangeable tranducers: Low-load (20 mN, 4 µm) & High-load (500 mN, 150 µm)
  • Rotation-tilt sample stage enabling 5-axis sample positioning

nanoScratch testing module:

Tribological measurements benefit directly from in-situ techniques which shed light on deformation processes occurring at the sliding interface. In addition to enabling direct observation of wear evolution, in-situ tribology can also be used for studies of friction, tribochemical reactions, interfacial adhesion, abrasion resistance, and nanoparticle rolling. nanoScratch testing is accomplished by applying a normal load in a controlled fashion while measuring the lateral force between the probe and sample. By selecting the appropriate normal loading profile and lateral displacement pattern, many different types of tests can be performed.

Electrical Characterization module (ECM mode):

ECM mode of the picoindenter provides a powerful solution for simultaneous in-situ electrical and mechanical measurements. Using a conductive path that connects the probe and sample, a voltage bias is applied to allow continuous measurement of evolving electrical contact conditions as a function of applied force and probe displacement. Site-specific testing can be performed by confirming proper tip placement with electron microscope imaging. Through-tip electrical measurements can also be used to gain insight into electromechanical properties of micro- or nano-structures such as pillars and particles.

Kammrath Weiss Tensile Testing Stage

Kammrath Weiss Technology  5kN Tensile Testing Module

This tensile module is designed to operate at loads upto 5kN with smooth and well controlled movement for testing with high precision and clear imaging. The displacement speed can range from 0.1 to 20μm/s. Similar to the Gatan tensile stage, this tensile test module is compatible with SEM-based analysis techniques such as ECCI and EBSD, enabling in-situ analysis of bulk-to-microscale sample during deformation process.

Kammrath Weiss Heating Module

Kammrath Weiss Technology MZ. H12 Specimen Heating Device 

A small heating unit is attached at the center of the specimen, focusing the heat directly to the point of interest. This heating module can be used as a stand-alone heating unit or in combination with the KW tensile stage; it can achieve a temperature range up to 1200 ºC. For better accuracy, specimens should be ground fairly thin (approx. 1mm). 

Bulge Test Setup

Bulge Test Setup for Multiaxial Deformation Experiment 

The bulge test setup was designed and created by the Tasan Group. With controlled multiaxial deformation capability, it can (i) create multiple and complex strain paths and (ii) track microstructure evolution. 

Applications:
  • Generation of multiple and complex strain paths in plate-type samples
  • Observation of site-specific microstructural features via high-resolution SEM techniques
  • Construction of forming limit curves by coupling with 3D Digital Image Correlation
Features
  • A custom sample holder adapted for EBSD/ECCI measurements
  • Washers of varied aspect ratios to generate multiple strain paths
  • Strain-path alteration when the sample touches the upper washer with a different opening

In-situ Hydrogen-Charging Setup for SEM

in-situ Electrochemical Hydrogen-Charging Setup for SEM

This electrochemical H-charging setup is compatible with high vacuum systems such as SEM, and provides (i) real-time microstructural analysis and (ii) mechanical analysis of H-induced effects.

In the setup, the objective sample surface of observation is isolated from a hydrogen source by the sample itself. By electrochemical reaction in the cell, hydrogen permeates into the sample from the surface contacting with the hydrogen source and diffuses into the whole sample volume. A clean objective surface without liquid contamination allows simultaneous microstructural and mechanical characterization during hydrogen absorption inside electron microscope. See here for our in-situ hydrogen embrittlement case studies utilizing this setup.

Applications:
  • High-resolution, SEM-based techniques (SE, BSE, ECCI, EBSD) during real-time hydrogen-charging
  • Nanomechanical analysis by coupling with SEM picoindenter system
  • In situ silver decoration for hydrogen-mapping by coupling with optical microscope
  • Quantitative analysis of hydrogen-permeation using mass spectrometer system
Features
  • Double-layered isolation of electrolyte
  • Galvanostat. electrochemical charging
  • Automated circulation of electrolyte
  • Versatile combinations with various microstructural analysis techniques

In-situ Hydrogen-Charging Setup for Synchrotron

in-situ Electrochemical Hydrogen-Charging Setup for Synchrotron

Similar to the in-situ hydrogen charging setup for SEM, this synchrotron compatible electrochemical H-charging setup provides simultaneous x-ray diffraction characterization during hydrogen permeation across the sample thickness.

Applications:
  • High-energy X-ray diffraction experiments during real-time hydrogen charging
Features
  • Isolated electrolyte
  • Minimized setup-synchrotron beam interaction
  • Galvanostat. electrochemical charging
  • Automated circulation of electrolyte

In-situ Mass-Spectroscopy Setup

In-situ Mass-spectrometer for SEM   -underdevelopment-

We are developing a new in-situ mass spectroscopy setup for scanning electron microscopes, which enables gas species quantification during microstructure characterizations. This in-situ setup can be coupled with SEM-based techniques such EBSD, ECCI, in-situ heating and cooling stages, and in-situ hydrogen-charging setup. We use this setup to study hydrogen embrittlement and provide insights in hydrogen segregation, trapping, and permeation in materials.

In-situ Fatigue Test Apparatus

In situ Fatigue Testing Apparatus   -underdevelopment-

We are developing a new quasi- in-situ multi-axial fatigue test setup for scanning electron microscopes, which enables rapid tracking of microstructural change during cyclic deformation. Combined with SEM-based techniques, the setup can provide the comprehensive information on strain and microstructural fields evolving in multi-axial cyclic stress states. We use this setup to study defect creation and crack propagation mechanisms in materials having high level of microstructural heterogeneity.