China develops world's most durable tungsten material

The team at the Chinese Academy of Sciences in Hefei, Anhui province, say they have developed the strongest tungsten material that can be used in a fusion furnace.

New manufacturing technology will allow tungsten to be used in the most demanding applications. Tungsten is one of the heaviest and hardest natural elements with the highest melting point of all metals (3,410 degrees Celsius). This material can improve the performance of devices used in extreme environments but is very brittle. A part manufactured entirely from tungsten powder often cracks or breaks easily if stretched or subjected to great pressure. In most practical applications, materials scientists must incorporate additional elements such as nickel, copper or iron to increase the ductility of the product.

Chinese companies produced 70,000 tons of tungsten in 2019.

In a paper published in February in the journal Acta Materialia, a team led by Professor Wu Xuebang at the Institute of Solid State Physics in Hefei said they had produced a large block of pure tungsten with high strength. tensile strength to 1.35 gigapascals at room temperature, higher than most tungsten alloys today. The researchers revealed their project was funded by the government's fusion program. The purer the tungsten, the lower the risk to fusion energy production, said Professor Fang Qianfeng, a member of the research team.

China's reactor, also known as the artificial sun, has the potential to produce almost limitless clean energy through a fusion reaction similar to the process that occurs at the core of the sun. Construction of the fusion reactor could be completed in the early 2030s. To produce energy, the reactor will need to heat hydrogen gas to 150 million degrees Celsius, 10 times the temperature of the Sun's core.

The hot gas will be held by the intense magnetic field, but the inner wall of the reactor will remain exposed to high heat, pressure and radiation. It is an extreme environment that most materials today cannot withstand. Tungsten brick kilns can tackle this challenge and keep a nuclear power plant running for years or even decades. For a long time, scientists tried to get rid of other impurities in tungsten, because impurities can cause unexpected disturbances to fusion reactions.

Wu and his colleagues say their technology also has many military applications. For example, warheads made from new tungsten materials can penetrate armor or concrete more effectively because of their greater strength and density. China has the largest tungsten mine in the world. Chinese companies produced about 70,000 tons of tungsten in 2019, accounting for more than 80% of the world's output. According to data from the US Geological Survey. The team in Hefei shares a relatively simple new material technology that can be easily scaled up for mass production.

Tungsten cannot be cured by casting because most industrial furnaces operate below 1,800 degrees Celsius, much lower than the melting point of this metal. Instead, workers will pour fine tungsten powder into the mold and heat it to more than 2,200 degrees Celsius until the powder adheres to a crystalline form. However, Wu and his colleagues reduced the temperature by more than a fifth, then forged the tungsten with a powerful hot hammer. This unique treatment creates a never-before-seen layer-stacked crystal structure that can absorb impact energy making the material strong yet flexible.