MTC and LTU test new laser-based welding method for fusion – initiated at AIMday

MTC Powder Solutions and Luleå University of Technology (LTU) have taken important first steps in testing a novel laser welding approach that could simplify the manufacturing process for components in fusion reactors such as ITER.

Replacing Beryllium with Tungsten – and the Manufacturing Challenge

With the transition from beryllium (Be) to tungsten (W) for the first wall panels in ITER, engineers face the complex task of creating strong, gas-tight bonds between tungsten and copper (Cu). Traditionally, Hot Isostatic Pressing (HIP) has been used for diffusion bonding, but this process requires encapsulating each component in a gas-tight seal – a challenging and time-consuming step when producing thousands of tiles.

MTC Powder Solutions proposed a new concept: creating a peripheral gas-tight seal along the bond line without fully encapsulating the tile. LTU suggested that laser welding could be the key to making this possible.

Pre-study with promising results

In this initial pre-study, LTU carried out laser welding trials using an IPG 15 kW laser operating at 4–8 kW. MTC Powder Solutions then analyzed the welds using advanced imaging and microscopy. The material was supplied by Fusion for Energy (F4E).

Despite challenges with the supplied tungsten geometry , a central hole made it difficult to achieve a perfect gas-tight weld – the results demonstrated that laser welding can indeed create a strong peripheral seal between tungsten and copper. High-speed imaging revealed good powder catchment and bead formation, and micrographs showed well-fused interfaces with minimal defects when parameters were optimized.

“Even though the initial geometry wasn’t ideal, we saw clear potential in this approach,” says Tomas Berglund, Project Leader at MTC Powder Solutions. “With adjusted tile design and optimized parameters, laser welding could become a highly efficient way to prepare tungsten-copper joints for HIP.”

Opening doors to more efficient production

The pre-study highlights how collaborative innovation can accelerate technical development for the Big Science sector. By combining MTC Powder Solutions’ expertise in advanced materials and LTU’s competence in laser processing, the partners have paved the way for a more streamlined and scalable manufacturing route for fusion reactor components.

The next step will be to refine the process parameters and geometry to ensure reliable, repeatable gas-tight welds, an important milestone for future energy technologies.