Scientists create most stable metal for precision manufacturing

Chinese and Austrian researchers have developed an alloy with practically zero thermal expansion across a vast temperature range

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A metal alloy has been developed by Chinese and Austrian scientists that barely expands over a vast temperature range. Photo: TU Wien

Published: 5:00pm, 7 Feb 2025

A metal alloy that barely expands over an “unprecedentedly” wide temperature range has been developed by Chinese and Austrian scientists – and it could have applications in aviation, aerospace and high-precision electronics.

The alloy undergoes practically zero expansion from temperatures far below freezing to above the boiling point of water.

Most metals expand as temperatures increase. The Eiffel Tower, for example, which is built of iron, famously grows up to 15cm (six inches) during summer before contracting in the cold months.

While manageable in large structures, this poses a significant challenge in applications that require high levels of precision, such as creating microchips.

Scientists are therefore always searching for materials that will not undergo significant expansion across a wide range of temperatures.

“To date, the number of zero thermal expansion materials is rare in nature,” the research team wrote in a paper published in the peer-reviewed journal National Science Review in December.

An alloy of iron and nickel called Invar is one known material with an extremely low thermal expansion that is used to create precision instruments such as clocks and some engine valves.