X-Ray Strain Scanner (D8 Discover)
The Bruker D8 Discover is an X-ray diffractometer configured for micro-diffraction and spatially resolved analysis. It is used primarily to measure residual stress and preferred crystallographic orientation, or texture, in solid materials. The instrument has a horizontal four-circle theta–2theta goniometer, a quarter Eulerian cradle and an automated XYZ sample stage. These features allow samples to be positioned, tilted, rotated and oscillated during measurement, improving results for coarse-grained materials.
Capabilities
The D8 Discover provides:
- Residual-stress measurement
- Crystallographic-texture analysis
- Micro-diffraction using small probe volumes
- Spatial mapping across components and selected regions
- Investigation of thin films and coatings
- Analysis of welded and surface-treated materials
- Measurement of coarse-grained polycrystalline materials
Interchangeable collimators provide beam diameters from 0.05 to 2 mm. Copper, cobalt and chromium X-ray tubes allow the wavelength to be matched to the material being investigated. Diffracted X-rays are recorded with a two-dimensional VANTEC-500 detector, which captures a large section of the Debye–Scherrer diffraction cones.
Applications
The D8 Discover supports investigations involving, but not limited to:
- Polycrystalline diamonds and carbonado
- Zirconium-carbide coatings
- Polycrystalline thin films
- Friction-stir welds
- Plasma-sprayed coatings
- Hydroxyapatite and tungsten-carbide–cobalt coatings
- Zinc-tin alloy coatings
- Hydrogenated titanium alloys
- Metallic implants and surface treatments
- Manufacturing-induced residual stress
Technical Specifications
X-ray Tubes | Cu (1.54 Å), Co (1.79 Å), Cr (2.29 Å) |
Incident beam conditioning | PG incident beam monochromator |
Beam diameters | 2.0, 0.8, 0.5, 0.3, 0.1, 0.05 mm |
Sample stage | ¼ Cradle with integrated φ, χ, x, y, z |
Sample setup | Video laser system, accurate to 20 microns |
Detector | Vantec 500 |
Two-theta range | 10° ≤ 2θ ≤ 108° (front) 10° ≤ 2θ ≤ 139° (back) |
x, y, z range | -75 mm ≤ X ≤ 75 mm -75 mm ≤ Y ≤ 75 mm -1 mm ≤ Z ≤ 11 mm |
Stress resolution | Approximately ±20 MPa |
Data Collection and Analysis
GADDS software is used to control the instrument and collect diffraction data. Residual-stress data are processed and analysed using Bruker LEPTOS, while crystallographic-texture measurements are analysed using Multex Area 2. Instrument scientists assist users with experimental planning, sample positioning, measurement selection, data processing and interpretation.
Project Example
The D8 Discover was used to investigate how treatment parameters affect residual stress in Ti-6Al-4V alloy implants. Spatially resolved measurements revealed changes in the magnitude and distribution of stress, providing information that can be used to assess and optimise treatment processes.
Instrument Scientist
Dr Tshepo Ntsoane
PhD Physics
Email: tshepo.ntsoane@necsa.co.za
Telephone: +27 (0)12 305 5400 or 5427
Apply for Beam Time
Prospective users should contact the instrument scientist to discuss project feasibility, sample requirements and instrument availability. The completed Beam Time Request Form must be submitted to the instrument scientist and the BLC User Office at UserOffice@necsa.co.za.
