Picosecond amorphization of SiO2 stishovite under tension

Masaaki Misawa, Emina Ryuo, Kimiko Yoshida, Rajiv K. Kalia, Aiichiro Nakano, Norimasa Nishiyama, Fuyuki Shimojo, Priya Vashishta, Fumihiro Wakai

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


It is extremely difficult to realize two conflicting properties-high hardness and toughness-in one material. Nanopolycrystalline stishovite, recently synthesized from Earth-abundant silica glass, proved to be a super-hard, ultra-tough material, which could provide sustainable supply of high-performance ceramics. Our quantum molecular dynamics simulations show that stishovite amorphizes rapidly on the order of picosecond under tension in front of a crack tip. We find a displacive amorphization mechanism that only involves short-distance collective motions of atoms, thereby facilitating the rapid transformation. The two-step amorphization pathway involves an intermediate state akin to experimentally suggested "high-density glass polymorphs" before eventually transforming to normal glass. The rapid amorphization can catch up with, screen, and self-heal a fast-moving crack. This new concept of fast amorphization toughening likely operates in other pressure-synthesized hard solids.

Original languageEnglish
Article numbere1602339
JournalScience Advances
Issue number5
Publication statusPublished - May 2017
Externally publishedYes

ASJC Scopus subject areas

  • General


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