Skip Navigation

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Okamoto, P. R.
Right arrow Articles by Ohnuki, S.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Okamoto, P. R.
Right arrow Articles by Ohnuki, S.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Journal of Electron Microscopy 48(5): 481-487 (1999)
© 1999 Oxford University Press

Do cracks melt their way through solids?

P. R. Okamoto1, N. Q. Lam1 and S. Ohnuki2,*

1Materials Science Division, Argonne National Laboratory Argonne, IL 60439, USA
2Department of Materials and Engineering, Hokkaido University Sapporo, Japan

*To whom correspondence should be addressed

Real-time, in-situ fracture studies in the high-voltage electron microscope (HVEM) show that microscopically thin regions of amorphous NiTi form ahead of moving crack tips in the B2-NiTi intermetallic compound. This occurs during tensile straining at temperatures equal to or below 600 K. The cut-off temperature of 600 K for this stress-induced melting (or amorphization) is identical to that reported in the literature for heavy-ion-induced amorphization of the intermetallic NiTi and for ion-beam-mixing-induced amorphization of Ni and Ti multilayers. The higher crystallization temperatures (~800 K) of NiTi, glasses produced by rapid quenching can also be reduced by heavy-ion irradiation to 600 K (but not lower than). This strongly suggests that ion-beam-induced relaxation processes allow the formation of a unique, fully relaxed glassy state characterized by a unique isothermal crystallization temperature. We believe this unique temperature is the Kauzmann isentropic glass-transition temperature of an ideal glassy state having the same entropy as the crystalline state. The formation of this ideal glassy state via solid-state disordering processes can be understood as the most energetically-favoured, kinetically-constrained melting response of crystalline materials driven far from equilibrium at very low temperatures.

Keywords     glass transition, amorphization, fracture, irradiation

Received     16 October 1998, accepted 24 March 1999


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.