Irradiation-enhanced second-phase precipitation in Zr-Fe nanocrystalline thin films

D. Kaoumi, A. T. Motta, R. C. Birtcher

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


In situ observations in a transmission electron microscope (TEM) were used to study ion-beam enhancement of second-phase precipitation in Zr-Fe nanocrystalline thin films. The free-standing films were prepared by co-sputter deposition with an Fe content of 1.2 at%. TEM diffraction analysis showed that only the hep Zr crystal structure was present in the as-deposited films. No second phases were detected, although Rutherford Backscattering Spectroscopy (RBS) confirmed a Fe content beyond the solubility limit of Fe in Zr (of the order of ppm). This means the thin films were Zr solid solutions supersaturated with Fe. Heat treatment in the absence of irradiation was observed to cause precipitation of the Zr2Fe intermetallic phase, but only above 673 K. The same second-phase precipitation can occur at lower temperatures in the presence of ion irradiation. Samples were irradiated in-situ at the Intermediate Voltage Electron Microscope (IVEM) at Argonne National Laboratory with Kr ions to fluences in excess of 1016 ion/cm2, at temperatures ranging from 50 to 573 K. Second phase precipitation was detected by electron diffraction patterns and by dark field imaging comparing regions exposed to the beam with regions protected from the beam by the TEM support grid. Precipitation of Zr2Fe intermetallic phase was observed at all irradiating temperatures above room temperature. In the bulk, this phase is thermodynamically metastable in the range of temperatures investigated (relative to the orthorhombic Zr3Fe intermetallic phase). The kinetics of the irradiation-enhanced second-phase precipitation was followed by recording the diffraction patterns at regular intervals. The dose to precipitation was found to decrease with increasing irradiation temperature.

Original languageEnglish (US)
Title of host publicationGrowth, Modification and Analysis by Ion Beams at the Nanoscale
PublisherMaterials Research Society
Number of pages6
ISBN (Print)1558998632, 9781558998636
StatePublished - 2005
Event2005 MRS Fall Meeting - Boston, MA, United States
Duration: Nov 28 2005Dec 2 2005

Publication series

NameMaterials Research Society Symposium Proceedings
ISSN (Print)0272-9172


Other2005 MRS Fall Meeting
Country/TerritoryUnited States
CityBoston, MA

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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