Effect of hydrogen on nanomechanical properties in Fe-22Mn-0.6C TWIP steel revealed by in-situ electrochemical nanoindentation. (March 2019)

• Record Type: Journal Article
• Authors: Wang, Dong; Lu, Xu; Deng, Yun; Guo, Xiaofei; Barnoush, Afrooz
• Is Part Of: Acta materialia. Volume 166(2019)
• Page Start: 618
• Page End: 629
• Publication Date: 2019-03
• Subjects: Hydrogen embrittlement -- Electrochemical nanoindentation -- TWIP steel -- Dislocation nucleation -- Nanohardness; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2018.12.055
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: In-situ electrochemical nanoindentation was applied to study the effect of hydrogen on the mechanical properties of Fe-22Mn-0.6C TWIP steel at nanoscale. Distinctive behaviors in three defined grain orientations: (001), (101), and (111) were investigated in a sequence of air, hydrogen ingress, and hydrogen egress processes. The obvious pop-in load drop caused by introducing hydrogen was analyzed using the classical dislocation theory in combination with the "Defactant" model, wherein hydrogen-enhanced homogeneous dislocation nucleation through the reduction of dislocation line energy and stacking fault energy were proposed as the reasons. The dependence of pop-in behaviors on crystallographic orientations was also discussed. Tabor relation-based models were applied to analyze the nanohardness increment, which was related to the hydrogen-enhanced lattice friction and the hydrogen-reduced plastic zone size. The different recovery behaviors of pop-in load and nanohardness during hydrogen egress were assessed according to the different amounts of residual hydrogen in the corresponding affected zone. Graphical abstract: Image 1