Acoustic emission signature of a martensitic transformation

The research focuses on the Ti-6Al-4V alloy (Ti64), a commonly used material in LPBF, enhanced with the addition of Fe as a β stabilizer. Incorporating 3 wt% and 6 wt% Fe into Ti64 led to significant changes in microstructural evolution, including reduced martensite formation and an increased volume of the β phase. These findings demonstrate the potential of in-situ alloying as a straightforward strategy to improve the material’s properties.

Acoustic Emission monitoring revealed acoustic signatures directly associated with phase transformations during the LPBF process. This represents the first detection of distinct AE footprints of martensitic transformations in LPBF, offering a powerful tool for real-time optimization of process parameters. Advanced ML algorithms classified AE signals with high accuracy, uncovering detailed insights into process stability and material behavior under varying conditions.

The integration of AE monitoring with operando synchrotron X-ray diffraction and advanced microscopy techniques provided a deeper understanding of how processing parameters influence microstructure and phase transformations. These complementary methods allowed for precise correlations between AE signals and the resulting material properties.

This study highlights the potential of AE monitoring as a versatile and cost-effective method for real-time quality control in LPBF. Coupled with in-situ alloying, this approach offers an efficient way to tailor microstructures and enhance mechanical properties without extensive post-processing. The findings mark a significant step forward in advancing additive manufacturing technologies, paving the way for the design and production of high-performance materials.