| About this Abstract |
| Meeting |
Materials Science & Technology 2020
|
| Symposium
|
Integration between Modeling and Experiments for Crystalline Metals: From Atomistic to Macroscopic Scales II
|
| Presentation Title |
Strong strain hardening in ultrafast melt-quenched
nanocrystalline Cu: the role of fivefold twins |
| Author(s) |
Amir Hassan Zahiri, Pranay Chakraborty, Yan Wang, Lei Cao |
| On-Site Speaker (Planned) |
Amir Hassan Zahiri |
| Abstract Scope |
Low ductility due to the absence of strain hardening effect in
the nanocrystalline and nanotwinned metals is one of the recent challenges. In this work, we studied melt-quenched nanocrystalline Cu under compression, which contains high-density of fivefold twins (ffts), twin boundaries, and stacking faults and we observed sustained strain hardening effect. The molecular dynamics simulations show that the observed strain hardening is due to the contribution of numerous dislocation reactions, constant nucleation, dislocations impedance, and restricted twin boundary migration in fft networks. We find that dislocations can nucleate and impede by the ffts and migration of the fft boundary is restricted by its own core. Moreover, due to the gliding of two different Shockley partial dislocations in the opposite directions fft boundary migrates by two atomic planes directly. Finally, dislocation transmission observed among the fft boundaries. This work presents the advantage of ffts over nanotwins to overcome the strength-ductility trade-off. |