NSF Funds Study of Solute Atom Clusters to Strengthen Metal Alloys

Solute clustering in Mg-2at.%Zn alloy
Solute clustering in the Mg-2at.%Zn alloy predicted by atomistic simulations.

Over the last couple of decades, researchers have been able to demonstrate that tiny groupings of solute atoms at the nanometer scale referred to as "solute clusters," have the potential to dramatically improve the strength of metal alloys. The process by which they do so is not yet fully understood, however, especially when compared to more conventional strengthening methods, such as precipitate strengthening, which involves growing hard particles in alloys to make them stronger.

Assistant Professor Yong-Jie Hu has received a three-year NSF grant to study solute cluster strengthening of Mg alloys to understand when and why the nanoscale clustering of solute atoms can work better than other strengthening mechanisms. It is anticipated that certain types of solute clusters, based on their chemical compositions and spatial arrangements, can be particularly potent at blocking the movement of dislocations, which are line defects in alloys that accommodate plastic deformation.

Through a combination of advanced experimental characterization and computer simulation techniques, Hu’s project seeks to understand the structure and spatial dispersion of solute clusters; explain how these solute clusters interact with dislocations at the nanometer scale; and quantify how much stronger these solute clusters can make the metal macroscopically. This is a collaborative research project, with experimental efforts carried out in the laboratory of Assistant Professor Kelvin Xie at Texas A&M University.

This research could lead to a new theory to quantitatively predict metal strength based on the presence of these solute clusters. Its significance lies in its potential to advance our knowledge of alloy strengthening, which could result in the development of stronger and lighter metallic materials for everything from cars to planes.

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