Advanced Material With Zero Thermal Expansion From 4 to 1,400 K Discovered
In the design of an aircraft, one must consider how the extreme heat of the launch and the extreme cold of space will affect the craft. Indeed, there are few materials that can withstand these temperature changes without deforming, making them very much in demand.
Now, a new team from the University of New South Wales (UNSW) has developed a material that exhibits zero thermal expansion from 4 to 1,400K (-269 to 1126 °C, -452 to 2059 °F). Better yet, the material is also composed mostly of readily available elements.
It consists of scandium, aluminum, tungsten, and oxygen. Of these elements, only the scandium is rare and costly and the scientists are already looking for a better alternative.
Perhaps the greatest part about this discovery is that it was made completely by accident.
"We were conducting experiments with these materials in association with our batteries-based research, for unrelated purposes, and fortuitously came across this singular property of this particular composition," UNSW Associate Professor Neeraj Sharma said in a statement.
Now, Sharma and his team are trying to figure out exactly how the material works. They speculate that perhaps bond lengths, angles, and oxygen atom positions are changing in concert with one another to preserve the overall volume intact.
“Is it the bond lengths that are expanding? Is it the displacement of the oxygen atoms? Or, is the whole polyhedral rotating? We have three factors that are correlating.
“At this point, it is not clear if one or all of these contributing factors are responsible for the stability over a range of temperatures and we are investigating further to try and isolate the mechanism,” Sharma added.
The scientists have called their new material orthorhombic Sc1.5Al0.5W3O12 and it has many applications ranging from aerospace design to electronics devices to even medical equipment. The research is available in the journal Chemistry of Materials.