Micro X-ray fluorescence (-XRF) methodology for quantitative elemental imaging of Al-Zn-Mg-Cu alloys with varying chemical compositions

The preparation and characterization of Al-Zn-Mg-Cu alloys with varying chemical compositions are helpful for rapid screening of the optimal compositions in the research and development of new materials. The traditional testing methods cannot accurately determine the composition gradient in samples because they have a low spatial resolution or are semi-quantitative and time-consuming. The micro X-ray fluorescence (mu-XRF) methodology has been used for the elemental imaging of Al-Zn-Mg-Cu alloys with varying chemical compositions. The experimental conditions, including testing voltages, testing currents and the dwell time for each pixel, were optimized systematically to improve the repeatability and accuracy of the mu-XRF methodology. The quantitative elemental imaging of an Al-Zn-Mg-Cu alloy rod sample using mu-XRF was performed, and the results were validated by conducting spark optical emission spectroscopy. The limits of detection of mu-XRF for Zn, Mg, and Cu were 0.007 wt%, 0.068 wt%, and 0.002 wt%, respectively. This versatile elemental imaging technique provided an effective means for the component analysis and process evaluation of alloy samples with a composition gradient and thus for research and development of new materials.