About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advanced Real Time Imaging for Materials Science and Processing: 10th Anniversary
|
| Presentation Title |
Watching a lattice bend: real-time in situ TEM of fracture in nanocrystalline Cu-W-Re down to the atomic scale |
| Author(s) |
Nicolas J. Peter, Jianxiao Cui, Daniel Kiener, Ruth Schwaiger |
| On-Site Speaker (Planned) |
Nicolas J. Peter |
| Abstract Scope |
Re-alloyed nanocrystalline Cu-W combines high strength and fracture toughness with outstanding bending ductility, yet the deformation mechanisms remain unresolved. Time-resolved in situ TEM allows for following crack propagation from the nanoscale to atomic resolution, tying observation directly to mechanism. Nanoscale fracture is intergranular yet ductile: cracks travel along Cu grain boundaries, deflect at stiff W inclusions, forming secondary cracks by void coalescence through thinning Cu ligaments. On the atomic scale, we follow one Cu ligament containing a grain boundary under quasi-uniaxial tension during the previously mentioned nanoscale crack propagation. We first observe intragranular plasticity instead of grain-boundary-mediated softening, and the formation of a discrete 10 degree intragranular rotation, consistent with a wedge-disclination-like defect. This defect abruptly delocalizes into a continuously bent crystal lattice, before grain boundary sliding finally sets in. This visualizes extended Volterra-type relaxation enabling extreme deformation before failure. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Characterization, High-Temperature Materials, Mechanical Properties |