Next big step in alloy discovery
Researchers from University of Technology Sydney and Australian Science and Technology Organisation (ANSTO) are using Raijin to predict the existence of new high temperature, strong and ductile alloys.
The new alloys could be suited to a wide range of applications from aircraft engine materials, to golf club heads. They could even offer a low-cost alternative to currently used alloys such as steels and superalloys.
“We have developed a new algorithm for alloy search and discovery,” explains PhD candidate Mr Daniel King.
“High-entropy alloys are the next big step in alloy discovery. We’re stepping away from the conventional alloys that have one primary element – steel is mostly iron, for example – and we’re alloying many elements together, typically four or five in equal concentrations.”
Until 2004, it was generally thought that such alloys would be brittle and undesirable, says Mr King.
“Since their discovery, high-entropy alloys have drawn a lot of attention due to their impressive mechanical properties, such as strength, hardness, and ductility, which is thought to be caused by the mixing of large concentrations of different sized atoms, leading to a distortion and inherent strain within the crystal lattice,” he says.
Previous models for predicting new high-entropy alloys have been unable to distinguish between brittle and ductile combinations.
By incorporating a comprehensive database for more than 70 periodic table elements into his computer program, Mr King has created an algorithm with the ability to search through more than 186,000,000 unique 4-, 5-, and 6-element combinations to predict the most stable alloys.
“Of those millions, we found 1,900 plausible new high-entropy alloys that hadn’t been reported on,” says Mr King.
“It’s now a matter of choosing 50 of the easiest and lowest-cost to make and see if they actually will perform as high-entropy alloys.”
Using Raijin, Mr King has benchmarked his algorithm to standard quantum mechanical models as well as more than 180 experimentally studied alloys from past literature. The results verify that his novel stability parameter works.
The research could have far-reaching industry applications.
“They’re mainly being looked at for structural applications,” says Mr King.
“My work with ANSTO has been specifically looking at high-entropy alloys as radiation tolerant materials for advanced nuclear reactors. I thought the best way to do this would be to create a computer algorithm to search for the best candidate alloy.”
Mr King has published the new algorithm at www.alloyasap.com