Deanna Csomo McCool | February 15, 2021
A “stable” material by physics standards means that it retains its properties unless drastic measures are taken to change them. Metastable materials, on the other hand, are materials that transform into more stable forms under the right conditions — but sometimes these materials exhibit more desirable traits than their stable counterparts.
The Department of Army has awarded a three-year grant to researchers at the University of Notre Dame to develop techniques to prepare some metastable metals for use in extreme conditions. The first metal being examined is a type of metastable nickel, but researchers will also investigate others, such as tungsten or cobalt, said Khachatur Manukyan, research assistant professor in the Department of Physics and affiliated member of ND Energy.
Under usual conditions, nickel is stable in the form of a cubic crystalline structure. But scientists have long known about a metastable variety, called hexagonal close-packed (HCP) nickel, in which the atoms are arranged differently. Some have claimed to have already created this material in the lab. However, others are skeptical because the processes can also create nickel carbide, which is difficult to discern from HCP nickel, according to Manukyan, the lead researcher on the project that also includes Tengfei Luo, professor of aerospace and mechanical engineering, and Alexander Mukasyan, research professor of chemical engineering.
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