Threshold Stress for High-Temperature Creep in Particle Strengthened Al-1.5 vol%Be Alloys

Ying Hwa Yeh, Shoji Goto, Hideo Yoshinaga, Hideharu Nakashima, Hiroaki Kurishita

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

High temperature creep of dispersion-strengthened Al-1.5 vol%Be alloy has been studied over a stress range 3.1 × 10-5~5.9 × l0-4E (E: the Young's modulus of Al matrix), which corresponds to 0.40~5.lσoror: the Orowan stress), at temperatures from 473 to 723 K. It is found that there occurs a threshold stress for creep deformation, σth, and the value of σth is approximately equal to that of σor and their ratio, σthor, is almost independent of the particle size and test temperature. At stresses below σth, plastic deformation of very slow rates takes place which may be associated with grain-boundary sliding and diffusional creep. In-situ HVEM observation reveals that the interaction between dislocation and particles is of attractive type and no dislocation line is visible at the particle/matrix interface, indicating that the stress field of a dislocation is almost completely relaxed at the interface. The observed threshold stress is discussed from the viewpoint of the attractive interaction.

Original languageEnglish
Pages (from-to)284-292
Number of pages9
JournalMaterials Transactions, JIM
Volume31
Issue number4
DOIs
Publication statusPublished - 1990

All Science Journal Classification (ASJC) codes

  • Engineering(all)

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