X-Ray Strain Scanner (D8 Discover)
D8 Discover instrument at the Necsa’s X-ray diffraction facility.
Instrument description
Necsa’s stress/strain instrument is a Bruker D8 Discover diffractometer that is specifically configured for micro-diffraction (small beam) applications. It is a horizontal four-circle theta-2theta orientated goniometer, that in addition is equipped with a ¼ Eulerian cradle and automated XYZ sample stage. For samples with large grain size, this enables sample oscillation during analysis for improved statistics. The instrument is ideal for the investigation of residual stresses, as well as determining preferred crystallographic effects in solid samples.
The instrument is equipped with tight incident beam collimation that is well-suited to micro-beam diffraction (small probe volumes) and spatially resolved analysis. The X-ray wavelength can be matched to the material being investigated by employing different X-ray tubes that include Cu, Co and Cr. Collection of the diffracted data is done using a 2-D Vantec500 detector that captures a large section of the diffracted DeBye Scherrer cones.
Technical
| 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 |
| Software | Stress: Leptos Texture: Multex Area 2 |
Resolution
Stress resolution typically to +-20 MPa accuracy.
Data Collection:
Data collection is performed via GADDS application on a dedicated instrument control computer.
Data reduction and analysis:
Data reduction and analysis is carried out using Bruker’s proprietary Leptos software.
Project examples
- Polycrystalline diamonds
- Carbonado’s
- ZrC coating
- Thin films (Cr99Al1 polycrystalline)
- Friction stir welds
- Plasma sprayed coating (Hydroxylapatite,WCCo, Zn-Sn etc)
- Hydrogenated Ti-6Al-4V Alloy
Variation of residual stress in Ti6Al4v alloy implants as function of treatment parameters.
Extract of research results that have benefitted from utilisation of the instrument:
- P. Oladijo, V. Luzin, N. B. Maledi, K. Setswalo, T. P. Ntsoane & H. Abe, Residual Stress and Wear Resistance of HVOF Inconel 625 Coating on SS304 Steel Substrate, Journal of Thermal Spray Technology volume 29, pages1382–1395 (2020)
O.P. Oladijo, M.H. Mathabatha, A.P.I. Popoola, T.P. Ntsoane, Characterization and Corrosion Behaviour of Plasma Sprayed Zn-Sn Alloy Coatings on Mild Steel, Surface and Coatings Technology, Vol 352, 2018, Pg 654-661, https://doi.org/10.1016/j.surfcoat.2017.04.029.
Z.P. Mudau, C.J. Sheppard, A.R.E. Prinsloo, A.M. Venter, T.P. Ntsoane and E.E. Fullerton, Residual stress in Cr99Al1 polycrystalline thin films. Acta Physica Polonica A, vol. 133, issue 3, pp. 578-581, 2018, 10.12693/APhysPolA.133.578
- Nsengiyumva, T.P. Ntsoane, M. Topic, L. Pichon, ‘Influence of Hydrogenation on Residual Stresses in Oxygen-Implanted Ti-6Al-4V Alloy’, Materials Research Proceedings, Vol. 4, pp 163-168, 2018, http://dx.doi.org/10.21741/9781945291678-25
Instrument scientist(s):
- Dr. Tshepo Ntsoane
- PhD Physics
- Email: tshepo.ntsoane@necsa.co.za
- Tel: +27 (0) 12 305 5400/5427
