Tuesday, October 14, 2025

Novel metal alloy withstands extreme conditions

A new high-temperature resistant material exhibits great potential for applications such as energy-efficient aircraft turbines

Karlsruher Institut für Technologie (KIT)

image:
*Alloy production by means of arc melting in the material synthesis lab of the Institute for Applied Materials – Materials Science and Engineering. (Photo: Chiara Bellamoli, KIT)*
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Credit: Chiara Bellamoli, KIT

High-temperature-resistant metallic materials are required for aircraft engines, gas turbines, X-ray units, and many other technical applications. Refractory metals such as tungsten, molybdenum, and chromium, whose melting points are around or higher than 2,000 degrees Celsius, can be most resistant to high temperatures. Their practical application, however, has limitations: They are brittle at room temperature and, in contact with oxygen, they start to oxidize causing failure within short time already at temperatures of 600 to 700 degrees Celsius. Therefore, they can only be used under technically complex vacuum conditions – for example as X-ray rotating anodes.

Due to these challenges, superalloys based on nickel have been used for decades in components that are exposed to air or combustion gases at high temperatures. They are used, for example, as standard materials for gas turbines. “The existing superalloys are made of many different metallic elements including rarely available ones so that they combine several properties. They are ductile at room temperature, stable at high temperatures, and resistant to oxidation,” explains Professor Martin Heilmaier from KIT’s Institute for Applied Materials – Materials Science and Engineering. “However – and there is the rub – the operating temperatures, i.e. the temperatures in which they can be used safely, are in the range up to 1,100 degrees Celsius maximum. This is too low to exploit the full potential for more efficiency in turbines or other high-temperature applications. The fact is that the efficiency in combustion processes increases with temperature.”

A Chance for a Technological Leap

This limitation existing with the materials available today was the starting point for Heilmaier’s working group. Within the “Materials Compounds from Composite Materials for Applications in Extreme Conditions” (MatCom-ComMat) research training group funded by the German Research Foundation (DFG), the researchers succeeded in developing a new alloy made of chromium, molybdenum, and silicon. This refractory metal-based alloy, in whose discovery Dr. Alexander Kauffmann, now professor at the Ruhr University Bochum, played a major role, features hitherto unparalleled properties. “It is ductile at room temperature, its melting point is as high as about 2,000 degrees Celsius, and – unlike refractory alloys known to date – it oxidizes only slowly, even in the critical temperature range. This nurtures the vision of being able to make components suitable for operating temperatures substantially higher than 1,100 degrees Celsius. Thus, the result of our research has the potential to enable a real technological leap,” says Kauffmann. This specifically remarkable as resistance to oxidation and ductility still cannot be predicted sufficiently to allow a targeted material design – despite the great progress that has been achieved in computer-assisted materials development.

More Efficiency, Less Consumption

“In a turbine, even a temperature increase of just 100 degrees Celsius can reduce fuel consumption by about five percent,” explains Heilmaier. This is particularly relevant to aviation, as airplanes powered by electricity will hardly be suitable for long-haul flights in the next decades. Thus, a significant reduction of the fuel consumption will be a vital issue. Stationary gas turbines in power plants could also be operated with lower CO₂ emissions thanks to more robust materials. In order to be able to use the alloy on an industrial level, many other development steps are necessary,” says Heilmaier. “However, with our discovery in fundamental research, we have reached an important milestone. Research groups all over the world can now build on this achievement.”

Original publication

Frauke Hinrichs, Georg Winkens, Lena Katharina Kramer, Gabriely Falcão, Ewa M. Hahn, Daniel Schliephake, Michael Konrad Eusterholz, Sandipan Sen, Mathias Christian Galetz, Haruyuki Inui, Alexander Kauffmann, Martin Heilmaier: A ductile chromium–molybdenum alloy resistant to high-temperature oxidation. Nature, 2025. DOI: 10.1038/s41586-025-09516-8

Being “The Research University in the Helmholtz Association”, KIT creates and imparts knowledge for the society and the environment. It is the objective to make significant contributions to the global challenges in the fields of energy, mobility, and information. For this, about 10,000 employees cooperate in a broad range of disciplines in natural sciences, engineering sciences, economics, and the humanities and social sciences. KIT prepares its 22,800 students for responsible tasks in society, industry, and science by offering research-based study programs. Innovation efforts at KIT build a bridge between important scientific findings and their application for the benefit of society, economic prosperity, and the preservation of our natural basis of life. KIT is one of the German universities of excellence.

Journal

Nature

DOI

10.1038/s41586-025-09516-8

Article Title

https://www.nature.com/articles/s41586-025-09516-8

Article Publication Date

8-Oct-2025

Satellite images reveal ancient hunting traps used by South American social groups

University of Exeter

Illustration of a chacu — image:
An illustration of a chacu, courtesy of Gerald Díaz-Vigil
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Credit: Gerald Díaz-Vigil

Satellite images have revealed an ancient system of elaborate, funnel-shaped mega traps likely built by hunters and pastoralists to catch prey in the high altitudes of northern Chile.

New research on the Andean landscape and the people who lived there has identified 76 stone ‘chacus’, often stretching hundreds of metres in length, that would have been used to capture vicuña, a wild relative of the alpaca.

Similar structures have been found in other arid regions of the world, including the Middle East, but this is the first time such a concentration has been discovered in the area, and it raises the possibility that they pre-date those known to have been used by the Inkas.

An archaeologist at the University of Exeter has also found evidence of settlements and outposts in the area known as the Western Valleys, establishing a high probability that it was home to foragers many centuries after it was believed people had adopted more settled agricultural social systems.

The study, by Dr Adrián Oyaneder, of Exeter’s Department of Archaeology and History, is published in the journal Antiquity, and is based on the research he conducted during his PhD.

“There has long been a discrepancy between what archaeological and ethnohistorical records have told us about life in the Western Valleys of northern Chile during the colonial period,” says Dr Oyaneder. “On the one hand, archaeological research has pointed to a gradual decline in hunting and gathering from 2,000 B.C. onwards with the introduction of domesticated plants and animals. But, historical sources, such as Spanish tax records from the 16th to the 19th centuries, refer to ‘Uru’ or ‘Uro’, which was a generic term for foraging populations who were of little economic interest to the colonisers.”

Using publicly available satellite data, Dr Oyaneder examined a 4,600 square-kilometre area of the Camarones River Basin, focusing on upland areas that had hitherto remained little studied. Over four months, he identified a huge number of new sites of archaeological interest.

Among them were 76 chacus, with the great majority being V-shaped traps formed by two ‘antennae’ built from dry-stone walls, around 1.5 metres in height and on average 150 metres in length. These funnelled down to an enclosure of around 95 square metres, which would have been dug or established to a depth of around two metres, sufficient to trap any animals driven into it by the hunters.

All the chacus were located on steep slopes, pointing downhill, with some employing natural topographical features to create one of the antennae. They were also at an altitude within the usual range of the vicuña.

“My reaction when I saw the first chacu was to double and even triple check it,” said Dr Oyaneder. “Initially, I thought it was a bit of a unique occurrence, but as I progressed with my survey, I realised that they were everywhere in the highlands and in a quantity never previously recorded in the Andes.

“And then when I began to read papers and books around the subject, particularly by Thérèse Bouysse-Cassagne and Olivia Harris, there was reference to the choquela, specialised vicuña hunting groups, and words referring specifically to chacu hunting people and chacu hunters.”

Dr Oyaneder identified almost 800 small-scale settlements, ranging from single buildings of no more than one square metre to groups of nine or more structures. These were plotted using GIS and grouped into likely clusters linked to nearby chacus and other settlements, all within a 5km distance.

“The picture that emerges is of a landscape occupied by a range of human groups from at least 6000 B.C. to the 18th century,” adds Dr Oyaneder. “These groups moved strategically across the highlands, tethered primarily to hunting resources, particularly vicuña. The evidence indicates overlapping lifeways, combining hunting-gathering with agropastoral practices, and a network of short-term seasonal settlements and outposts to help people move across rugged and difficult terrain.”

Dr Oyaneder is now conducting further research to date some of these sites and establish whether they represent the first examples of their kind in the Andean region.

A tethered hunting and mobility landscape in the Andean highlands of the Western Valleys, northern Chile is published in Antiquity and was funded by the Becas Chile-ANID doctoral scholarships programme and a FONDECYT project by the same agency, led by Dr Daniela Valenzuela (Universidad de Tarapacá).

Aerial photo of a double chacu

Credit

Dr Adrian Oyaneder