Gunkelmann N, Tramontina DR, Bringa EM, Urbassek HM (2014)
Publication Language: English
Publication Status: Published
Publication Type: Journal article, Original article
Publication year: 2014
Publisher: Institute of Physics: Open Access Journals / Institute of Physics (IoP) and Deutsche Physikalische Gesellschaft
Book Volume: 16
DOI: 10.1088/1367-2630/16/9/093032
Strong shock waves create not only plasticity in Fe, but also phase transform the material from its bcc phase to the high-pressure hcp phase. We perform molecular-dynamics simulations of large, 8-million atom nanocrystalline Fe samples to study the interplay between these two mechanisms. We compare results for a potential that describes dislocation generation realistically but excludes phase change with another which in addition faithfully features the bcc -> hcp transformation. With increasing shock strength, we find a transition from a two-wave structure (elastic and plastic wave) to a three-wave structure (an additional phase-transformation wave), in agreement with experiment. Our results demonstrate that the phase transformation is preceded by dislocation generation at the grain boundaries (GBs). Plasticity is mostly given by the formation of dislocation loops, which cross the grains and leave behind screw dislocations. We find that the phase transition occurs for a particle velocity between 0.6 and 0.7 km s(-1). The phase transition takes only about 10 ps, and the transition time decreases with increasing shock pressure.
APA:
Gunkelmann, N., Tramontina, D.R., Bringa, E.M., & Urbassek, H.M. (2014). Interplay of plasticity and phase transformation in shock wave propagation in nanocrystalline iron. New Journal of Physics, 16. https://dx.doi.org/10.1088/1367-2630/16/9/093032
MLA:
Gunkelmann, Nina, et al. "Interplay of plasticity and phase transformation in shock wave propagation in nanocrystalline iron." New Journal of Physics 16 (2014).
BibTeX: Download