Hiroshima University Researchers Crack the Code for 3D Printing Tungsten Carbide, One of Industry's Hardest Materials
A Hiroshima University team used a hot-wire laser technique to 3D print defect-free tungsten carbide-cobalt exceeding 1,400 HV hardness, opening a path to cheaper, less wasteful production of cutting tools and industrial components.
Overview
Researchers at Hiroshima University have demonstrated a new additive manufacturing method capable of producing defect-free tungsten carbide-cobalt (WC-Co), one of the hardest engineered materials in industrial use. The technique, published in the International Journal of Refractory Metals and Hard Materials (April 2026 print edition), achieved hardness exceeding 1,400 HV on the Vickers scale — a level surpassed only by materials such as sapphire and diamond.
The breakthrough addresses a longstanding barrier in advanced manufacturing: tungsten carbide’s extreme hardness and brittleness have made it nearly impossible to process through conventional 3D printing methods without introducing cracks, porosity, or material degradation.
What We Know
The team, led by Assistant Professor Keita Marumoto at Hiroshima University’s Graduate School of Advanced Science and Engineering, developed a hot-wire laser irradiation approach in collaboration with Mitsubishi Materials Hardmetal Corporation. Unlike standard laser-based 3D printing, which fully melts metal powders, this technique combines a laser beam with a preheated filler wire to soften — rather than melt — the tungsten carbide-cobalt feedstock, as reported by ScienceDaily.
The researchers tested two deposition strategies. In the rod-leading approach, a cemented carbide rod is advanced ahead of the laser. In the laser-leading configuration, the laser irradiates the gap between the rod and an iron base material. Each strategy presented distinct tradeoffs: the rod-leading path promoted WC decomposition in upper layers, while the laser-leading path struggled to maintain consistent hardness, according to Interesting Engineering.
To resolve both issues, the team introduced a nickel alloy-based interlayer and tightly controlled processing temperatures — keeping heat above cobalt’s melting point while staying below the threshold that triggers excessive WC grain growth. The result was defect-free cemented carbide with no visible porosity or WC breakdown, as reported by Tom’s Hardware.
“Cemented carbides are extremely hard materials used for cutting tool edges and similar applications, but they are made from very expensive raw materials such as tungsten and cobalt, making reduction of material usage highly desirable,” Marumoto said, as quoted by Interesting Engineering. “By using additive manufacturing, cemented carbide can be deposited only where it is needed, thereby reducing material consumption.”
Why It Matters
Tungsten carbide-cobalt is a workhorse material in heavy industry, used extensively in cutting tools, mining drill bits, dies, and construction equipment. Conventional production relies on powder metallurgy — a process requiring high pressure, elevated temperatures, and extended sintering cycles that waste significant quantities of expensive raw materials. Complex geometries are particularly costly to produce, and design modifications are slow to implement.
The additive approach deposits WC-Co only where structurally needed, potentially reducing both material waste and production costs. If scaled, the technique could allow manufacturers to produce customized cutting tools and wear-resistant components with geometries that powder metallurgy cannot economically achieve.
What We Don’t Know
Several questions remain before the method can move from laboratory demonstration to factory floor. Cracking during fabrication has not been fully eliminated, and the researchers have acknowledged that producing complex shapes — the primary advantage of additive manufacturing — requires further development. The study used an iron base material, and the behavior of the process with other substrates is unexplored.
Long-term mechanical performance data, including fatigue resistance and wear rates under industrial conditions, have not yet been reported. It is also unclear how the process scales: hot-wire laser deposition rates, build volumes, and repeatability at production speeds have not been characterized in the published work.
The research was a collaboration between a university lab and Mitsubishi Materials Hardmetal Corporation, but neither party has announced commercialization timelines or pilot production plans.
Analysis
The ability to additively manufacture cemented carbides at industrial-grade hardness levels represents a meaningful step for the 3D printing industry, which has steadily expanded from polymers to conventional metals but has largely been unable to process ultra-hard materials. If the cracking and complexity challenges are resolved, the technique could find early adoption in niche applications where material costs are high and geometries are difficult — precisely the conditions where additive manufacturing’s economics are most favorable.
For now, the work remains a proof of concept rather than a production-ready process, but it opens a research direction that could eventually reshape how some of industry’s most demanding components are made.