Relating mechanical properties with dislocation cores in Ni3Ge-Fe3Ge intermetallic alloys

T. John Balk, Mukul Kumar, Kevin J. Hemker

Research output: Contribution to journalConference articlepeer-review

1 Scopus citations

Abstract

The transition from positive to negative temperature dependence of 0.2% yield stress is investigated in the model pseudo-binary Ni3Ge-Fe3Ge system. Ni3Ge and Fe3Ge, both L12 intermetallic alloys, show complete solid solubility as Fe is continuously substituted for Ni across the composition range. However, Ni3Ge exhibits the yield stress anomaly, whereas the yield stress of Fe3Ge shows a normal decline with temperature. Mechanical testing has verified this behavior, with the anomalous behavior gradually disappearing with increasing Fe content. It is proposed that this transition results from changes in the structure of dissociated superdislocation cores. Alloys with anomalous behavior from this system are characterized by the presence of screw superdislocations locked in the Kear-Wilsdorf (KW) configuration. Conversely, alloys with normal yield stress dependence are observed to contain curvilinear superdislocations that glide on the cube planes. Results from mechanical testing are presented and correlated with TEM observations of deformation structures. These results are discussed in light of planar fault energies determined through computer simulations of images.

Original languageEnglish
Pages (from-to)641-646
Number of pages6
JournalMaterials Research Society Symposium Proceedings
Volume460
StatePublished - 1997
EventProceedings of the 1996 MRS Fall Meeting - Boston, MA, USA
Duration: Dec 2 1996Dec 5 1996

ASJC Scopus subject areas

  • Materials Science (all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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