|About this Abstract
||Materials Science & Technology 2020
||Interfaces and Phase Transformations
||Study of Strain Rate and Temperature Dependent Behavior of Pseudo-morphic bcc Mg within the Mg/Nb Nanocomposites
||Manish Jain, Rajaprakash Ramachandramoorthy, Marko Knezevic, Nenad Velisavaljevic, Nathan A. Mara, Irene J. Beyerlein, Johann Michler, Siddhartha Pathak
|On-Site Speaker (Planned)
In this work, interface strain engineering of Mg with Nb was exploited to pseudo-morphically transform hexagonal closed packed (hcp) Mg into a stable body centered cubic (bcc) Mg at ambient pressures. The adjacent Mg/Nb interfaces were spaced within a few nanometers forming multilayered Mg/Nb nanocomposite. Transmission electron microscopy (TEM) and X-Ray diffraction (XRD) studies reveal that in physical vapor deposition (PVD) deposited Mg/Nb multilayers at lower thicknesses of ~5 nm, Mg undergoes an interface strain induced phase transition from hcp to bcc. We performed in situ SEM micro-pillar compression tests at strain rates from 0.001/s to 1000/s and temperatures from -90 oC to 225 oC on Mg (bcc)/Nb 5nm/5nm and Mg (hcp)/Nb 20nm/20nm nanolaminates to compare the responses of hcp vs. bcc Mg under such extreme loading conditions. Results from these tests are analyzed in terms of the measured activation energies and activation volumes from sub-micrometer sized Mg/Nb multilayer nanocomposites.