Introduction of Quantitative Analysis of Aluminum Alloys and Matching Function

Significance of Topic

Aluminum alloys are essential in automotive, aerospace and recycling industries due to their light weight, strength and corrosion resistance. Accurate determination of alloying elements, especially light elements like magnesium, is critical for process control, material certification and quality assurance. The Shimadzu EDX-8100 energy dispersive X-ray fluorescence spectrometer addresses previous limitations in light element detection, enabling reliable analysis of Mg at concentrations as low as 0.1 wt%.

Objectives and Study Overview

This application note presents two main analytical approaches for aluminum alloy characterization using the EDX-8100:

• Quantitative analysis by calibration curve method, including calibration preparation and repeatability assessment.
• Fundamental parameter (FP) based qualitative/quantitative analysis combined with a matching search function for rapid alloy identification.

Methodology and Instrumentation

• Calibration Curve Method
  Standard samples MSS-1100, MSS-2024, MSS-3004, MSS-5182 and MSS-7075 plus pure aluminum reference were measured. Calibration curves for Si, Fe, Cu, Mn, Mg, Cr, Zn and Ti were constructed. Matrix corrections (dj and lj methods) were applied to account for interelement absorption and spectral overlaps.
• Repeatability Test
  Ten replicate measurements of MSS-2024 assessed precision. Relative standard deviations ranged from 0.4% for Fe to 4.4% for Ti, confirming stable performance.
• FP Qualitative/Quantitative Analysis and Matching Function
  Full spectrum FP analysis matched against an aluminum alloy library. Sample MSS-3004 yielded the highest hit score, correctly identifying the alloy series and grade.

Used Instrumentation

• Spectrometer model: Shimadzu EDX-8100
• Detector: Silicon drift detector
• X-ray tube: Rhodium anode
• Tube voltage: 15 kV for light elements, 50 kV for heavier elements
• Collimator: 10 mm aperture
• Primary filters: None, filters #2 – #4 depending on element group
• Measurement atmosphere: Vacuum
• Integration times: 300 s for calibration; up to 300 s ×3 for FP groups

Main Results and Discussion

Calibration curves demonstrated excellent linearity across the alloy range. Accuracy (standard deviation σ) for Mg was 0.0077% or better. Mg Kα peaks, previously obscured, were clearly resolved even at ~1 wt%. FP matching reliably distinguished alloy grades, supporting rapid identification without extensive calibration for each grade.

Repeatability data confirmed <2% RSD for most elements, highlighting robust measurement stability. Overlap corrections improved Fe and Mn quantitation, while matrix corrections enhanced Mg accuracy.

Benefits and Practical Applications

• Enables routine quantitation of Mg and other light elements in aluminum alloys.
• Supports quality control, process monitoring and alloy certification in manufacturing.
• Facilitates acceptance testing of recycled aluminum feedstocks.
• Matching function streamlines rapid alloy grade identification without full recalibration.

Future Trends and Potential Applications

Emerging developments include automated workflows integrating XRF data with production control systems and machine learning algorithms for predictive alloy classification. Miniaturized and portable EDXRF units may extend on-site analysis in scrap processing and field inspection. Expanded spectral libraries and advanced matrix correction models will further enhance light element accuracy and broaden material coverage.

Conclusion

The Shimadzu EDX-8100 delivers highly sensitive, accurate analysis of light elements such as Mg in aluminum alloys. Calibration curve and FP matching approaches provide complementary routes for quantitation and alloy identification. This versatile instrument enhances quality assurance, process control and recycling workflows in aluminum production.

Reference

• T. Nakao and H. Moriya, Introduction of Quantitative Analysis of Aluminum Alloys and Matching Function, Shimadzu EDX-8100 Application Note, First Edition: Oct. 2022