A significant breakthrough has recently been achieved in the field of engineering materials: the innovative method of 3D printing tungsten carbide-cobalt (WC–Co), a material renowned for its exceptional hardness. However, this very hardness has made traditional shaping methods both challenging and inefficient. The current manufacturing process tends to be both costly and wasteful, and there is an urgent need for a more economically viable approach to produce these valuable materials.
Cemented carbides, particularly WC-Co, play a crucial role in demanding industries that require high durability and resistance to wear, such as cutting tools and construction equipment. Traditionally, these materials have been produced using powder metallurgy, a process that combines WC and Co powders under high pressure and sintering conditions. While this established method yields robust and hard products, it also results in substantial material waste and does not maximize yield efficiency.
To address these issues, a recent study has introduced an exciting new technique utilizing additive manufacturing (AM), commonly known as 3D printing, along with hot-wire laser irradiation. This innovative approach allows for the production of cemented carbides that preserve their hardness and durability while simultaneously minimizing material waste and reducing overall costs.
The research findings were published online in December 2025 in the International Journal of Refractory Metals and Hard Materials, with a print version set to appear in April 2026. As part of this study, the authors focused on employing AM, specifically through the hot-wire laser irradiation technique, which involves the integration of a laser beam with a preheated filler wire. This combination enhances the deposition rate—essentially how quickly the filler metal is added—improving the process's efficiency.
Two main fabrication methods were explored in this experiment. The first method involves directly irradiating a cemented carbide rod, allowing the rod to dictate the direction of the fabrication process. In contrast, the second method features the laser leading the way, where the laser irradiates the area between the base material (iron) and the bottom of the cemented carbide rod. Rather than melting the materials entirely, both methods soften them, facilitating the formation of the cemented carbide.
As noted by Keita Marumoto, the corresponding author and assistant professor at Hiroshima University's Graduate School of Advanced Science and Engineering, "Cemented carbides are incredibly hard materials typically used for cutting tool edges, but the raw materials like tungsten and cobalt are quite expensive. Therefore, finding ways to reduce material usage is highly advantageous. By utilizing additive manufacturing, we can deposit cemented carbide precisely where it is needed, significantly lowering material consumption."
The outcomes of this research indicate that the proposed method successfully maintains the hardness and mechanical integrity characteristic of conventionally manufactured WC-Co cemented carbides, achieving a hardness exceeding 1400 HV—a standard measuring resistance to penetration. This level of hardness ranks among the toughest materials available in industry, just shy of superhard substances such as sapphire and diamond. Producing defect-free cemented carbide molds appears feasible, which is a primary goal of this study, although some variations in results have been observed.
For instance, the rod-leading method showed some decomposition of WC at the upper section of the build, resulting in defects. Similarly, the laser-led technique faced challenges in sustaining the necessary hardness. To combat these issues, a nickel alloy-based middle layer was introduced. Alongside diligent temperature management—keeping temperatures above cobalt's melting point yet below levels that could encourage grain growth—this led to the successful creation of cemented carbide via AM without compromising hardness.
These promising results pave the way for further advancements in this field. Researchers aim to build on their findings by addressing cracking issues and exploring the fabrication of more intricate shapes.
Marumoto further emphasized, "The concept of forming metals by softening rather than fully melting them is groundbreaking, with potential applications extending beyond cemented carbides to a variety of other materials."
Looking ahead, the focus will shift toward fabricating cutting tools, investigating the use of alternative materials, and enhancing durability. This collaborative research effort included contributions from Keita Marumoto and Motomichi Yamamoto of Hiroshima University, as well as Takashi Abe, Keigo Nagamori, Hiroshi Ichikawa, and Akio Nishiyama from Mitsubishi Materials Hardmetal Corporation.
