|About this Abstract
||Materials Science & Technology 2019
||Advances in Understanding of Martensite in Steels
||Substructure of Lenticular Martensite Formed from Austenite Containing Hydrogen in Fe-31Ni Alloy
||Akinobu Shibata, Masanori Enoki, Nahoko Saji, Hirotaka Tai, Motomichi Koyama, Hiroshi Ohtani, Kaneaki Tsuzaki, Nobuhiro Tsuji
|On-Site Speaker (Planned)
It is well known that hydrogen degrades mechanical properties, that is, hydrogen embrittlement. However, there still remains a possibility for utilizing hydrogen effectively in steels if we can understand accurately influence of hydrogen on microstructures and properties of steels. The present study investigated effect of hydrogen on martensitic transformation behavior in an Fe-31Ni alloy. In both the hydrogen-charged and uncharged specimens, typical lenticular martensite plates formed after sub-zero cooling. However, the fraction of twinned region (including area of midrib) in lenticular martensite plate increased with increasing in hydrogen content, indicating that the existence of hydrogen facilitated twinning deformation as a lattice invariant deformation. Because the TEM observations and the first-principles calculations suggested that hydrogen might increase tetragonality of martensite, we concluded that solid solution hardening and increasing in tetragonality of martensite by hydrogen were the possible reasons for the facilitating twinning deformation as a lattice invariant deformation in martensitic transformation.
||Definite: At-meeting proceedings