A Revisited Mechanism of the Graphite-to-Diamond Transition at High Temperature

Sheng cai Zhu, Xiao zhi Yan, Jin Liu, Artem R. Oganov, Qiang Zhu

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

The graphite-diamond transition, under high-pressure and high-temperature conditions, has been a central subject in physical science. However, its atomistic mechanism remains under debate. Employing large-scale molecular dynamics (MD) simulations, we report a mechanism whereby the diamond nuclei in the graphite matrix propagate in two preferred directions, among which the graphite [120] is about 2.5 times faster than [001]. Consequently, cubic diamond (CD) is the kinetically favorable product, while only a few hexagonal diamonds (HDs) can exist as the twins of CDs. The coherent interface of t-(100)gr//(11-1)cd + [010]gr//[1-10]cd observed in MD simulation was confirmed by our high-resolution transmission electron microscopy experiment. The proposed mechanism not only clarifies the role of HD in graphite-diamond transition but also yields atomistic insight into strengthening synthetic diamond via microstructure engineering.

Original languageEnglish
Pages (from-to)864-878
Number of pages15
JournalMatter
Volume3
Issue number3
DOIs
Publication statusPublished - 2 Sep 2020

Keywords

  • crystal growth
  • interfaces
  • MAP 3: Understanding
  • molecular dynamics simulation
  • phase transition
  • superhard materials

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