- Itzhak Halevy: Pressure-Induced Crystal-Structure Transition in Fe-Cr Alloys
- 24. 4. 2019, 14:10
- lecture room F2, first floor Ke Karlovu 5
- more information
Abstract:
Elemental Iron undergoes crystal-structure transition from bcc (Im-3m space group) to hcp (P63/mmc space group) structure type under the pressure of 13 GPa. With increasing Cr-concentration, the structure transition is shifted to higher pressures (e.g. 18 GPa for Fe70Cr30). For Cr-concentrations higher than 47% we did not see any traces of the phase transition probably because the maximum pressure used (35 GPa) was not high enough to induce the structure transition in the alloys. After releasing the pressure, the cubic symmetry is restored. The Bulk modulus is increasing from 160 GPa (elemental Fe) with increasing Cr concentration up to approx. 30% Cr. Then it starts to decrease again followed by another increase and subsequent decrease represented by a double-peak dependence on Cr concentration. Hydrogen exposure of Fe80Cr20, resulting in negligible H absorption to the surface layers, does not bring any significant changes to the crystal- structure properties.