Dislocation structure and activated slip systems in β-Silicon nitride during high temperature deformation

K. Kawahara, S. Tsurekawa, H. Nakashima

Research output: Contribution to journalConference article

5 Citations (Scopus)

Abstract

β-Silicon nitride (Si3N4) with sintering additives of 5mass% Y2O3 and 4mass% Al2O3 was deformed by compression at temperatures from 1820 to 2020K and at strain rates from 9×10-6 to 2×10-4 s-1. Dislocation structures were examined by transmission electron microscopy (TEM) to identify the slip systems activated during high temperature deformation. It was found that the high temperature deformation behavior of β-Si3N4 depended strongly on the deformation condition. A good ductility as well as 10% in plastic strain occurred without crack formation under the limited condition of higher temperatures and lower strain rates. Both from the Burgers vector analysis using the weak-beam method and from the trace analysis on TEM, most of dislocations operating during deformation were found to be c dislocations belonging to the {101̄0}[0001] primary slip system. In addition to c dislocations, a dislocations on a {101̄0} 〈12̄10〉 prism slip were often observed. However, a+c dislocations on the {112̄1} 〈2̄113〉 pyramidal slip were only activated under the limited conditions where a good ductility had been appeared by compression. It has been considered, therefore, that the occurrence of ductility would be closely related to the activation of the pyramidal slip system.

Original languageEnglish
Pages (from-to)825-832
Number of pages8
JournalKey Engineering Materials
Volume171-174
Publication statusPublished - 2000
EventProceedings of the 1999 8th International Conference on Creep and Fracture of Engineering Materials and Structures - Tsukuba, Jpn
Duration: Nov 1 1999Nov 5 1999

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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