Hard as Steel, Printed Like Plastic: Scientists 3D Print One of Earth’s Toughest Metals

A Long-Standing Manufacturing Challenge

Researchers at Hiroshima University have developed a breakthrough technique that allows engineers to 3D print tungsten carbide–cobalt (WC–Co), one of the hardest engineering materials on Earth. Industries widely use this ultra-hard composite in cutting tools, mining equipment, and heavy-duty machinery because it resists wear and extreme heat. However, those same qualities have long prevented manufacturers from using conventional 3D-printing methods to shape it.

Most metal 3D-printing techniques work by melting metal powder and depositing it layer by layer. Tungsten carbide, however, behaves differently. When engineers fully melt the material, its internal structure can break down, which leads to cracks and weaker components. Because of this problem, manufacturers have struggled for years to produce complex tungsten-carbide shapes using additive manufacturing.

A Laser-Driven Solution

To solve this challenge, the Hiroshima University team created a new approach that softens the material instead of completely melting it. The researchers used a technique called hot-wire laser deposition, where a laser heats a tungsten carbide rod while a heated wire carefully controls the temperature during printing.

This controlled heating allows the printer to deposit the material layer by layer while preserving its internal structure. The team also placed thin nickel-based alloy layers between the printed layers to strengthen bonding and reduce the risk of cracks. As a result, the finished parts retained a hardness of more than 1,400 on the Vickers hardness scale, confirming that the process preserved the material’s exceptional durability.

A New Future for Industrial Manufacturing

This breakthrough could reshape the way industries manufacture ultra-hard tools. Currently, factories produce most tungsten carbide components through powder-based sintering, a process that requires extreme temperatures, high pressure, and specialized molds. With 3D printing, engineers could create complex designs while reducing both material waste and manufacturing costs.

Although the method still requires further development, the researchers believe their “softening rather than melting” strategy could eventually make it possible to 3D print other extremely hard materials as well.

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