Analysis of titanium powder for additive manufacturing with ARL EQUINOX 100 XRD and ARL QUANT’X XRF Systems

Significance of the Topic

The rise of additive manufacturing for complex metal parts has created a critical need for thorough characterization of metal powders. Ensuring the phase purity, crystallite size, and elemental composition of feedstock materials like Ti-6Al-4V directly impacts the mechanical performance and reliability of printed components in aerospace, biomedical, and industrial applications.

Aims and Study Overview

This study aims to combine X-ray diffraction (XRD) and energy-dispersive X-ray fluorescence (EDXRF) to evaluate the structural and elemental properties of Ti-6Al-4V (TC4) powders used in additive manufacturing. The goal is to detect oxidation, quantify crystallite size, and identify potential contaminants that may compromise part quality.

Methodology

Powder samples were analyzed by powder XRD in reflection geometry under Cu-Kα radiation for 5 minutes. Diffractograms were processed with Rietveld refinement in MDI JADE 2010 using the ICDD PDF4+ database to determine phase composition and crystallite size via Scherrer’s equation. Semi-quantitative EDXRF analysis was performed on sealed powder cups under a helium atmosphere, and spectra were converted to elemental concentrations using the UniQuant standardless software.

Used Instrumentation

• ARL EQUINOX 100 X-ray Diffractometer: Custom Cu (50 W) or Co (15 W) micro-focus tube with mirror optics and curved position sensitive detector for rapid, real-time diffraction measurements without external chillers.
• ARL QUANT’X Energy-Dispersive XRF Spectrometer: Silicon drift detector with 50 W Rh or Ag tube (up to 50 kV), capable of quantifying elements from Na (Z=11) to Am (Z=95) using UniQuant fundamental parameters.

Main Results and Discussion

XRD analysis identified a predominant Ti0.85Al0.15 α-phase (97.1 wt%) and a minor V11O16 oxide phase (2.9 wt%), with no β-Ti phase detected. Calculated crystallite sizes were 18.8 nm for the Ti alloy and 31.4 nm for V11O16, indicating that individual particles comprise aggregates of smaller crystallites.

EDXRF results showed 83.6 wt% Ti, 8.5 wt% Al, and 3.6 wt% V, closely matching the expected composition, while revealing unexpected Fe (2.5 wt%) and Cr (1.0 wt%) contamination likely introduced during powder production. Trace elements such as Mg, Ni, Mo, Mn, Co, Cu, Zr, and Sn were also detected at sub-percent levels, demonstrating the sensitivity of the combined approach.

Benefits and Practical Applications

The integration of XRD and EDXRF provides a comprehensive, non-destructive workflow for phase identification, crystallite sizing, and accurate elemental quantification without requiring extensive calibration standards. This dual-technique strategy enables rapid quality control and assurance of additive manufacturing powders, ensuring material integrity prior to printing.

Future Trends and Potential Uses

Advancements in portable XRD and handheld XRF instrumentation promise on-site powder assessment and real-time monitoring of batch consistency. Coupling these analytical tools with machine learning algorithms and automated data management could further optimize process controls and accelerate feedback loops in industrial additive manufacturing environments.

Conclusion

The combined use of ARL EQUINOX 100 XRD and ARL QUANT’X EDXRF systems offers a robust, user-friendly solution for the detailed structural and compositional evaluation of Ti-6Al-4V powders. By revealing phase distributions, crystallite dimensions, and trace contaminants, this methodology supports enhanced quality assurance and ultimately contributes to the reliability of additively manufactured metal parts.

References

• Dr. Simon Welzmiller, Dr. Pascal Lemberge. Application Note XR-AN41121, Thermo Fisher Scientific Inc., 2019.