BROWSE

Related Researcher

Author's Photo

Kwon, Oh Hoon
Ultrafast Laser Spectroscopy and Nano-microscopy (ULSaN Lab)
Research Interests
  • Femtochemistry/biology, 4D electron microscopy, structural dynamics, materials phenomena

ITEM VIEW & DOWNLOAD

Direct Observation of Martensitic Phase-Transformation Dynamics in Iron by 4D Single-Pulse Electron Microscopy

Cited 25 times inthomson ciCited 25 times inthomson ci
Title
Direct Observation of Martensitic Phase-Transformation Dynamics in Iron by 4D Single-Pulse Electron Microscopy
Author
Park, Hyun SoonKwon, Oh HoonBaskin, J. SpencerBarwick, BrettZewail, Ahmed H.
Keywords
Atomic displacement; Barrier-crossing; Body-centered cubic; Central zone; Complex solids; Direct observation; Face-centered cubic; Heating pulse; In-situ; Indirect process; Interface movement; Martensitic phase; Martensitic phase transformations; Nano films; Phase transformation; Rate determining step; Real time; Real-space; Selected area diffraction; Single-pulse; Temperature range; Time-scales
Issue Date
2009-11
Publisher
AMER CHEMICAL SOC
Citation
NANO LETTERS, v.9, no.11, pp.3954 - 3962
Abstract
The in situ martensitic phase transformation of Iron, a complex solid-state transition Involving collective atomic displacement and Interface movement, Is studied In real time by means of four-dimensional (4D) electron microscopy. The Iron nanofilm specimen Is heated at a maximum rate of -1011 K/s by a single heating pulse, and the evolution of the phase transformation from body-centered cubic to face-centered cubic crystal structure Is followed by means of single-pulse, selected-area diffraction and real-space imaging. Two distinct components are revealed in the evolution of the crystal structure. The first, on the nanosecond time scale, is a direct martensitic transformation, which proceeds In regions heated Into the temperature range of stability of the fee phase, 1185-1667 K. The second, on the microsecond time scale, represents an indirect process for the hottest central zone of laser heating, where the temperature Is initially above 1667 K and cooling Is the ratedetermining step. The mechanism of the direct transformation involves two steps, that of (barrier-crossing) nucleation on the reported nanosecond time scale, followed by a rapid grain growth typically in ∼100 ps for 10 nm crystallites.
URI
Go to Link
DOI
10.1021/nl9032704
ISSN
1530-6984
Appears in Collections:
PHY_Journal Papers
Files in This Item:
2-s2.0-72849145288.pdf Download

find_unist can give you direct access to the published full text of this article. (UNISTARs only)

Show full item record

qrcode

  • mendeley

    citeulike

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

MENU