| About this Abstract |
| Meeting |
MS&T22: Materials Science & Technology
|
| Symposium
|
Integration between Modeling and Experiments for Crystalline Metals: From Atomistic to Macroscopic Scales IV
|
| Presentation Title |
Role of Dislocations and Deformation Twinning on the High-pressure Phase Transformation in Zirconium |
| Author(s) |
Arul Kumar Mariyappan, T Yu, Y Wang, Rodney J McCabe, Carlos Tome, Laurent Capolungo |
| On-Site Speaker (Planned) |
Arul Kumar Mariyappan |
| Abstract Scope |
Using X-ray synchrotron and neutron diffraction techniques, the role of slip dislocations and deformation twins on the α-to-ω phase transformation (PT) in high purity zirconium is investigated. In-situ X-ray synchrotron-based quasi-hydrostatic pressure experiments are performed on pre-strained Zr-samples to capture the effects of pre-existing slip dislocations and twins on PT. These high-pressure experiments reveal that pre-existing prismatic <a> dislocations and tensile twins favor the PT compared to pyramidal<c+a> dislocations and compression twins. The pressure required to start and end the α-to-ω PT is lower for existing prismatic<a> dislocations and tensile twined microstructures. The neutron diffraction-based in-situ pressure-hold experiments are performed to understand the PT kinetics. These experiments reveal that the PT rate increases with the holding pressure. Detailed analysis of the experimental data in connection with the Avrami equation finds that the nucleation and migration rates of slip dislocations increase with the imposed pressure and thus accelerate the α-to-ω PT. |