Hiroshima University 3D Prints Ultra-Hard Tungsten Carbide with Novel Tech

Scientists at Hiroshima University have achieved a breakthrough in additive manufacturing, successfully 3D printing tungsten carbide–cobalt (WC–Co), one of the hardest materials used in industrial tools. This achievement overcomes a significant hurdle in materials science, as the inherent toughness of these ultra-hard materials has historically made them difficult to process using 3D printing techniques.

The research team, led by assistant professor Keita Marumoto, employed a novel “hot-wire irradiation method” to soften the WC–Co material rather than fully melting it during the 3D printing process. Traditional methods often lead to grain growth and defects when attempting to melt such hard materials. By carefully controlling the heat input with a laser, the team was able to build up additive layers without compromising the material’s integrity. A nickel alloy-based middle layer was strategically inserted between these additive layers to further optimize the process.

The resulting material boasts a hardness exceeding 1400 HV (Vickers hardness), a level approaching that of sapphire, and diamond. Crucially, this hardness was achieved without introducing defects or decomposition into the material’s structure. This represents a significant advancement, as maintaining material properties during additive manufacturing of ultra-hard substances is a persistent challenge.

“The approach of forming metal materials by softening them rather than fully melting them is novel, and it has the potential to be applied not only to cemented carbides, which were the focus of this study, but also to other materials,” stated Keita Marumoto. This suggests the technique could be adapted for a wider range of difficult-to-process materials in the future.

The team, which also includes Takashi Abe, Keigo Nagamori, Hiroshi Ichikawa, Akio Nishiyama, and Motomichi Yamamoto, is now focused on refining the process. Current efforts are directed towards mitigating cracking issues observed during printing and expanding the technique’s capabilities to create more complex geometries.

3D printing with metals, in general, presents considerable difficulties compared to plastics. Metallic alloys require precise temperature control and undergo complex phase changes during processing. This new technique addresses some of those challenges specifically for ultra-hard materials, and also offers a potential reduction in material waste compared to traditional manufacturing methods.

This development could have significant implications for industries relying on high-performance cutting tools, wear-resistant components, and specialized industrial parts. The ability to 3D print these materials on demand could lead to faster prototyping, customized designs, and reduced lead times.