Comparison of the structure of grain boundaries and properties of superplastic 40HNU, 47HNM, and 67KN5B alloys

Abstract

A comparison of the structure and properties of 47HNM, 40HNU and 67KN5B alloys possessing superplasticity is performed. It is shown that during superplastic deformation in the grain-boundary layers of these alloys the systems of tetrahedral close-packed clusters with Frank-Kasper structures are formed. The use of cluster models allows attributing the manifestation of ferromagnetic properties in superplastic materials to a change in the electron density. A qualitative agreement with the experiment is confirmed by the calculation of the spectra of spin-polarized electrons performed for the cluster structures.