| About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
|
| Symposium
|
Advances in Materials and Systems for a Hydrogen Economy
|
| Presentation Title |
Dynamic Nano and Microscale Processes in Hydrogen Charged Metals and Alloys |
| Author(s) |
Wendy Gu, Andrew Lee, Adam Barsotti, Jiyun Kang |
| On-Site Speaker (Planned) |
Wendy Gu |
| Abstract Scope |
In-situ synchrotron transmission X-ray microscopy (TXM) and Kelvin Probe Force Microscopy (KPFM) are used to image iron, nickel, Hastelloy and pipeline steel that simultaneously undergo electrochemical hydrogen charging and straining. Using TXM, we observe void-mediated crack growth during both transgranular and intergranular failure, and the initiation of cracks at nano-precipitates. Microcracking is observed to increase with strain rate, yet corresponds to an increase in macroscopic ductility. KPFM reveals that hydrogen is concentrated at grain boundaries at a low plastic strain, but is distributed throughout grain boundaries and grain interiors at a higher plastic strain. Hydrogen concentration is highest at intermediate grain boundary misorientation angles (~35 degree). This provides evidence for mechanisms in which hydrogen interactions with grain boundaries, phase boundaries and dislocations lead to void formation and crack propagation, and mobile vs. trapped hydrogen have a distinct influence on plasticity. |