Everything You Need to Know About 3D Printing with Tungsten

Tungsten has emerged as a pivotal material in the 3D metal printing industry. Intensive research in recent years has focused on maximizing its potential. With continuous advancements in tungsten applications for additive manufacturing, a significant breakthrough was achieved in 2020, overcoming longstanding issues of brittleness and micro-cracking during production. In 2021, a new process for creating tungsten-nickel-iron alloys was developed, further expanding its utility. Additionally, tungsten shows promise in fusion energy, where it can endure the extreme temperatures and conditions of fusion reactors, potentially meeting future energy needs. Here, we provide a comprehensive overview of this versatile heavy metal.

Properties of Tungsten

The name “tungsten” comes from the Swedish term for “heavy stone,” reflecting its status as the heaviest technical metal. Tungsten is a refractory, shiny white material with a 19.25 g/cm³ density and can become brittle even with slight contamination. It also has the highest melting point of all metals, at 3,410°C, and a boiling point of 5,700°C, making it ideal for use in light bulbs.

Tungsten in its pure form. (Photo Credits: ©vvoe – stock.adobe.com)

In its pure form, tungsten is either very soft or brittle, and it is almost always combined with other elements to form alloys known for their hardness. The most well-known alloy is tungsten carbide, a mixture of tungsten and carbon that creates a ceramic composite material. Other combinations include high-speed steel and alloys with cobalt, copper, bronze, chromium, iron, or nickel. Tungsten is also a component of the nickel-molybdenum-chromium superalloy Hastelloy. In all cases, these alloys result in rigid materials.

Applications and Advantages

Due to its properties, such as heat and heat resistance, the metal is primarily used in the aerospace and defense sectors. Tungsten can often be found in rocket engine nozzles, tools, turbine blades for aircraft, and weapon heads. In medicine, the material is also an attractive option for MRI scans, collimators, or radiation protection, as it has radiation-shielding properties. Tungsten is also used in the automotive sector, chemical industry, and even leisure applications. It is also found in ion generation devices, including cathodes and anodes.

Tungsten is biocompatible, absorbs X-rays and gamma rays, and is resistant to most acids. Due to its resistance to corrosion, erosion, and thermal conductivity, tungsten alloys are used in the gravity die casting of aluminum. Overall, the material’s properties make it suitable for various applications.

Technologies

Tungsten is currently processed using two methods. Selective laser melting (SLM) uses an infrared laser to melt the powder and join layers. Initially, printing with tungsten presented technical difficulties due to its high melting point. However, this was overcome by combining pure tungsten powder with nickel-iron or nickel-copper. The heavy metal also offers an excellent alternative to harmful lead in aluminum casting. The second process is binder jetting. In collaboration with a material manufacturer, ExOne has developed a copper-tungsten composite material used in laser beam machines. The EBM process has also been successfully adapted to tungsten. The advantage of the process is that the metal can be preheated, thus preventing deformation and residual stresses.

Complex parts that can be manufactured using the tungsten-nickel-iron alloy. (Photo Credits: Wolfram Industrie GmbH)

Leading Companies on the Market

There are several companies involved in 3D printing with tungsten. The Swedish company Höganäs AB is a leading player that uses tungsten-titanium carbide as a mixed carbide additive for cutting tools and producing tungsten-based sintered carbide. GE Additive, a significant player in metal 3D printing, is also researching materials, including tungsten. ExOne is known for its binder jetting technology, which works with heavy metals. Other companies, such as EOS and Desktop Metal, are working on many projects involving metal. 3D Systems created a print parameter database license for tungsten a year ago, which is 3D printed on the DMP Flex 350 metal 3D printer.

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*Cover Photo Credits: ExOne Pressemitteilung