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Title: Grain size dependence of dynamic mechanical behavior of AZ31B magnesium alloy sheet under compressive shock loading

The effects of grain size on the dynamic deformation behavior of rolled AZ31B alloy at high strain rates were investigated. Rolled AZ31B alloy samples with grain sizes of 6, 18 and 37 μm, were subjected to shock loading tests using Split Hopkinson Pressure Bar at room temperature and at a strain rate of 1100 s{sup −} {sup 1}. It was found that a double-peak basal texture formed in the shock loaded samples. The strength and ductility of the alloy under the high strain-rate compressive loading increased with decreasing grain size. However, twinning fraction and strain hardening rate were found to decrease with decreasing grain size. In addition, orientation imaging microscopy showed a higher contribution of double and contraction twins in the deformation process of the coarse-grained samples. Using transmission electron microscopy, pyramidal dislocations were detected in the shock loaded sample, proving the activation of pyramidal slip system under dynamic impact loading. - Highlights: • A double-peak basal texture developed in all shock loaded samples. • Both strength and ductility increased with decreasing grain size. • Twinning fraction and strain hardening rate decreased with decreasing grain size. • ‘g.b’ analysis confirmed the presence of dislocations in shock loaded alloy.
Authors:
 [1] ; ;  [1] ; ;  [2]
  1. Department of Mechanical Engineering, University of Saskatchewan, Saskatoon (Canada)
  2. Department of Applied Physics, Chalmers University of Technology, Göteborg (Sweden)
Publication Date:
OSTI Identifier:
22476142
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 106; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; DEFORMATION; DISLOCATIONS; DUCTILITY; GRAIN SIZE; LOADING; MAGNESIUM ALLOYS; ORIENTATION; STRAIN HARDENING; STRAIN RATE; TEMPERATURE RANGE 0273-0400 K; TEXTURE; TRANSMISSION ELECTRON MICROSCOPY; TWINNING