| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
General Poster Session
|
| Presentation Title |
L-33: Integrated Study of First-principles Calculations and Experimental Measurements for Hydrogen Effect on FCC to HCP Martensitic Transformation |
| Author(s) |
Satoshi Iikubo, Kenji Hirata, Yui Kuroki, Shoya Kawano, Hiroshi Ohtani, Motomichi Koyama, Kaneaki Tsuzaki |
| On-Site Speaker (Planned) |
Satoshi Iikubo |
| Abstract Scope |
Hydrogen, which can act as an interstitial species in steels, has been recognized to promote phase transformation from FCC to HCP. However, we reported a dramatic effect of interstitial hydrogen that suppresses this hcp phase transformation experimentally. More specifically, the fraction of hcp phase that forms during cooling decreases with increasing diffusible hydrogen content. To understand this new finding, first-principles calculations were employed to investigate the effect of hydrogen on the chemical driving force of the transformation of iron from the FCC to HCP phase. The minimum energy path from FCC to HCP phases shows that FCC becomes stable with increasing hydrogen content. Furthermore, vibrational contribution to the free energy destabilizes HCP phase with hydrogen, throughout the temperature region. These results explain the observed anomalous suppression of the martensitic transformation in the hydrogen-charged steel. |
| Proceedings Inclusion? |
Undecided |