Scientists 3D Print Tungsten Carbide — One of the Hardest Metals on Earth

Scientists have achieved a breakthrough in additive manufacturing by successfully 3D printing tungsten carbide-cobalt (WC-Co) — one of the hardest materials used in industrial applications. The research, published in the International Journal of Refractory Metals and Hard Materials, opens new possibilities for producing cutting tools and wear-resistant components with significantly reduced material waste.

The Challenge

Tungsten carbide-cobalt cemented carbides are prized for their extreme hardness and wear resistance, making them essential for cutting tools, construction equipment, and industrial machinery. However, traditional manufacturing through powder metallurgy consumes large amounts of expensive raw materials — particularly tungsten and cobalt — while delivering relatively modest yields.

The Solution: Hot-Wire Laser Irradiation

Researchers from Hiroshima University and Mitsubishi Materials explored a new approach using additive manufacturing combined with hot-wire laser irradiation. This technique pairs a laser beam with a heated filler wire, increasing deposition rates and improving overall manufacturing efficiency.

By using additive manufacturing, cemented carbide can be deposited only where it is needed, thereby reducing material consumption, said Keita Marumoto, assistant professor at Hiroshima University Graduate School of Advanced Science and Engineering.

Achieving Industrial Hardness

The experiments demonstrated that this AM strategy can preserve the hardness and mechanical strength typically achieved through conventional manufacturing. The resulting material reached hardness levels above 1400 HV — ranking just below superhard materials like sapphire and diamond.

Key to success was introducing a nickel alloy-based intermediate layer combined with careful temperature control (above the cobalt melting point but below the temperature of grain growth). This enabled defect-free cemented carbide production.

Future Applications

The approach shows promise for fabricating cutting tools with complex geometries that would be difficult or impossible to achieve through traditional methods. Future work will focus on reducing cracking during fabrication and enabling more intricate shapes.

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 but also to other materials, noted Marumoto.