I don't know what kind of application this will have in the real world, but I can't imagine they would have been working on creating it without a need for it. https://in.mashable.com/science/7392/researchers-have-found-the-strongest-silver-alloy Crystallographic defects are irregularities in the geometrical structure of crystalline solids. The defects cause changes in physical properties of the metal which can be undesirable like, brittleness and softening. So the metals are combined with impurities- other metals or nonmetals to create alloys that only have the desirable properties of the metal while the defects are removed. Researchers have used the process to create the world’s strongest silver that is 42% stronger than the previous strongest. The team of scientists from UVM, Lawrence Livermore National Lab, the Ames Laboratory, Los Alamos National Laboratory and UCLA published their study in the journal Nature Materials titled, ‘Ideal maximum strengths and defect-induced softening in nanocrystalline-nanotwinned metals’. Co-author of the study Frederic Sansoz, University of Vermont explained, “We've discovered a new mechanism at work at the nanoscale that allows us to make metals that are much stronger than anything ever made before—while not losing any electrical conductivity.” Generally, material with defects on doping- addition of impurities, gain strength but lose electrical conductivity as seen in semiconductors. Co-author Morris Wang from Lawrence Livermore National Laboratory said that the team wanted to develop a way to retain electrical conductivity and gain strength. The researchers achieved that by mixing trace amounts of copper with the silver which monopolized on two inherent defects in the atomic arrangement of silver. By Hall-Petch relation, as the size of a crystal decreases the strength of a crystal increases. When crystals of metal are infinitesimally small the boundaries between them become unstable and start moving. And another method to strengthen metals like silver that uses coherent twin boundaries- pattern of crystal is mirrored across the boundary. This deformation increases strength of materials exponentially. But the twin boundaries turn soft when the interspacing decreases below a critical size of a few nanometers, due to imperfections. The study has found an "ideal maximum strength" for metals with twin boundaries under seven nanometers apart and the heat-treated version of this silver-copper mixture had hardness above the theoretical maximum.
