High-temperature deformation mechanism of B2-type NiAl intermetallic compound deduced from stress relaxation behavior

Tsukasa Ono, Akihiko Chiba, Xing Guo Li, Shuji Hanada

Research output: Contribution to journalArticlepeer-review

Abstract

In order to study mechanisms of high temperature deformation of NLM intermetallic compound with a B2-type crystal structure, internal stresses (σi) and effective stresses (σe) have been estimated by stress-relaxation tests conducted in the temperature region from 1223 to 1373 K. Two methods, i.e., Kikuchi's method and Li's method, are used to analyze the results of the relaxation behavior. The mobile dislocation densities remain constant during the relaxation tests in the temperature range tested so that Kikuchi's method and Li's method is relevant for analyzing the relaxation behavior of NiAl. The internal stresses and effective stresses estimated from the two methods are in relatively good agreement with each other. The ratio of internal stress σi to flow stress σs, (i.e., σis) indicates that the flow stress includes the effective stress and that the pure metal type and alloy type high temperature deformation mechanisms coexist in high temperature deformation. Activation volume of the mobile dislocation is 102 to approximately 103 b3, indicating that effective stress in NiAl is related to dragging stress of jogged screw dislocations. Thus mobile dislocations in NiAl at high temperatures move viscously as a result of the dragging stress acting on jogged screw dislocations and not as a result of the lattice friction associated with the Peierls stress.

Original languageEnglish
Pages (from-to)948-954
Number of pages7
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Volume64
Issue number10
DOIs
Publication statusPublished - 2000

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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