| Title |
Microscopic Mechanism of the Hydrogen damage Effect on Softening Behavior |
| Authors |
권동일(Don Gil Kwon); 김학민(Hak Min Kim); 이성학(Sung Hak Lee); 장영원(young Won Chang) |
| Abstract |
The influence of hydrogen on the plastic flow and fracture was studied using smooth and notched tensile specimens. Cathodic charging was performed at current densities varying from 0.04 mA/㎠ to 2 mA/㎠ under controlled galvanostatic conditions. The introduction of high-fugacity hydrogen into the matrix by electrocharging caused irreversible internal damage in the absence of stress at current densities above 0.2 mA/㎠. Hydrogen damage was closely related to softening behavior such as the suppression of yield-point phenomenon and the degradation of mechanical strength observed in the hydrogen-charged case. During tensile testing a number of surface cracks were developed from subsurface damages, resulting in a reduction of work-hardening rates compared to the uncharged case. To effectively analyze these changes in plastic properties after hydrogen charging, hydrogen-induced softening phenomenon was discussed in terms of microscopic dislocation behavior around local particle interfaces. |