Fraunhofer UltraGRAIN Breakthrough: In-Process Metal 3D Printing Control Achieves 75% Grain Size Reduction

Breakthrough in Metal Additive Manufacturing

Researchers from Fraunhofer-Gesellschaft and RMIT University have achieved a significant breakthrough in metal additive manufacturing, demonstrating a method to control the grain structure of metal components during the printing process itself.

The UltraGRAIN project, which concluded on February 25, 2026, focused on laser-based directed energy deposition (DED-LB) and developed a scalable approach for tailoring microstructures directly during the build process.

How It Works

Controlling microstructure has been a longstanding challenge in metal AM. Grain structures tend to form naturally during solidification and are difficult to modify locally—yet these structures profoundly influence mechanical properties like fatigue strength, service life, and load-bearing performance.

The UltraGRAIN team initially explored ultrasound to affect solidification behavior, then pivoted to pulsed-laser excitation of the melt pool—a non-contact technique that works with complex geometries and industrial equipment.

"The pulsed laser approach directly excites the melt pool during deposition... offers greater scalability than ultrasonic techniques."

75% Grain Size Reduction

Testing on demonstrator components showed remarkable results:

• Up to 75% reduction in grain size
• Locally optimized zones within a single component
• Integration into existing DED systems possible

This level of control allows engineers to create components with varying mechanical properties in different areas—something previously only achievable through post-processing or multiple manufacturing steps.

Industry Applications

Industries poised to benefit include:

• Aerospace
• Automotive manufacturing
• Energy technology
• Turbomachinery
• Tool and mold making

Components with locally optimized microstructures could improve performance while reducing material usage and extending service life.

Collaboration Behind the Breakthrough

The UltraGRAIN consortium included:

• Fraunhofer IWS (Material and Beam Technology)
• Fraunhofer IAPT (Additive Manufacturing Technologies)
• RMIT University, Melbourne

"UltraGRAIN shows how Fraunhofer IWS develops new manufacturing technologies consistently from concept to industrial application," said Professor Christoph Leyens, Director of Fraunhofer IWS. "The results offer significant scientific insight and provide an excellent foundation for future industrial transfer."

In December 2025, Fraunhofer IWS signed MOUs with RMIT University and Swinburne University of Technology to support future research and technology transfer in advanced manufacturing.