Mechanical glass transition revealed by the fracture toughness of metallic glasses

Jittisa Ketkaew, Wen Chen, Hui Wang, Amit Datye, Meng Fan, Gabriela Pereira, Udo D. Schwarz, Ze Liu, Rui Yamada, Wojciech Dmowski, Mark D. Shattuck, Corey S. O’Hern, Takeshi Egami, Eran Bouchbinder, Jan Schroers

Research output: Contribution to journalArticlepeer-review

95 Citations (Scopus)


The fracture toughness of glassy materials remains poorly understood. In large part, this is due to the disordered, intrinsically non-equilibrium nature of the glass structure, which challenges its theoretical description and experimental determination. We show that the notch fracture toughness of metallic glasses exhibits an abrupt toughening transition as a function of a well-controlled fictive temperature (Tf), which characterizes the average glass structure. The ordinary temperature, which has been previously associated with a ductile-to-brittle transition, is shown to play a secondary role. The observed transition is interpreted to result from a competition between the Tf-dependent plastic relaxation rate and an applied strain rate. Consequently, a similar toughening transition as a function of strain rate is predicted and demonstrated experimentally. The observed mechanical toughening transition bears strong similarities to the ordinary glass transition and explains the previously reported large scatter in fracture toughness data and ductile-to-brittle transitions.

Original languageEnglish
Article number3271
JournalNature Communications
Issue number1
Publication statusPublished - 2018 Dec 1


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