Paper Title:
Etch Pit Observation of Dislocations in Early Deformation of Cu-Al Alloy and Pure Mg Polycrystals
  Abstract

In order to make clear the micro-yielding mechanisms of polycrystalline metals including twins, the movement of dislocations in the surface grains of Cu-6.8at%Al alloy and pure Mg polycrystals during the early stages of deformation was directly observed by using etch pit technique. The fresh dislocations multiply from the Frank-Read sources within the grains, and pile up against the twin and grain boundaries of two kinds of specimens. The pile-up dislocations on the primary and/or secondary slip planes are also confirmed in Cu-6.8at%Al alloys. Especially during the compressive loading for pure Mg, the occurrence of deformation twins is remarkable with an increase of strain rate, whereas the distribution of fresh dislocations tends to decrease in the surface grains. The present results suggest that the effect of twin boundaries on micro-yielding is almost equivalent for that of grain boundaries, which act as barriers to moving dislocations even in the pre-yield deformation.

  Info
Periodical
Key Engineering Materials (Volumes 345-346)
Edited by
S.W. Nam, Y.W. Chang, S.B. Lee and N.J. Kim
Pages
25-28
DOI
10.4028/www.scientific.net/KEM.345-346.25
Citation
Y. Nishimura, N. Ono, S. Miura, "Etch Pit Observation of Dislocations in Early Deformation of Cu-Al Alloy and Pure Mg Polycrystals ", Key Engineering Materials, Vols. 345-346, pp. 25-28, 2007
Online since
August 2007
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Price
$32.00
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