Features of fracture in single-phase (fcc) and two-phase (fcc+bcc) Fe95Ni5 samples have been studied

Employees of the laboratory for computer-aided design of materials based on molecular dynamics modeling have studied the features of fracture in single-phase (fcc) and two-phase (fcc+bcc) Fe95Ni5 samples with a gradient grain structure under uniaxial tension. It was revealed that destruction always begins and spreads along grain boundaries. The destruction process has three stages of development. At the first stage of destruction, nanopores nucleate and spread along the boundaries of large grains. The total volume of nanopores at this stage slowly increases due to the formation of new nanopores. The second stage is characterized by a rapid increase in the total volume of nanopores, associated both with the nucleation of nanopores and with an increase in their size. At the third stage, an increase in the total pore volume occurs through an increase in size and the merging of several nanopores. It was found that two-phase samples have higher crack resistance compared to single-phase ones. This behavior is due to bcc-fcc phase transitions, which contribute to more efficient accommodation of the structure during loading and push the onset of fracture towards large deformations.

The work was carried out within the framework of the state assignment of the Institute of Physics and Applied Mathematics of the Siberian Branch of the Russian Academy of Sciences (project FWRW-2021-0002) and the Russian Science Foundation grant No. 20-79-10406.
The results were published in the journal Metals (Q1).
Korchuganov A., Kryzhevich D., Zolnikov K. Fracture of Fe95Ni5 alloys with gradient-grained structure under uniaxial tension // Metals. - 2023. - Vol. 13, I. 7. - article 1308.
https://doi.org/10.3390/met13071308