A. R. Kuznetsov, S. A. Starikov, V. V. Sagaradze

PHONON INSTABILITIES IN A METAL ON THE BAIN FCC–BCC TRANSFORMATION PATH

In this paper, the energy of the Bain path in Al and the instability of phonons during uniaxial compression deformation along <001> are studied ab initio. It is shown that, at a strain of about 15%, dynamic loss of structure stability is observed due to short-wavelength phonons, which thus determine the theoretical strength of Al. Deformation causes shifts along the {111} planes of the initial fcc cell, leading to the formation of stacking faults. A similar formation of stacking faults was observed in [1] in the framework of simulation of compression along the <001> Ni3Al nanoparticle (L12 superstructure based on the fcc structure). The results obtained can be applied to situations in the experiment, when small defect-free regions are deformed, for example, as in nanostructured materials and during nanoindentation.

Acknowledgment: The work was performed under the state assignment from the Russian Ministry of Education and Science, theme Structure, No. 122021000033-2. The calculations were made with the use of the Uran supercomputer, IMM UB RAS.

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