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In-situ X-ray diffraction studies of slip and twinning in the presence of precipitates in AZ91 alloy

Version 2 2024-06-04, 03:54
Version 1 2016-08-30, 23:45
journal contribution
posted on 2024-06-04, 03:54 authored by SR Kada, Peter LynchPeter Lynch, JA Kimpton, Matthew BarnettMatthew Barnett
The effect of basal plate precipitates on the hardening of basal slip and {101¯2} twinning modes was investigated for a non-aged and aged AZ91 alloy in the twin dominated strain paths. Exploiting in-situ synchrotron and laboratory based X-ray diffraction methodologies, we quantified the critical resolved shear stress (CRSS) for basal slip and twinning modes. The twin volume fraction changes were quantified from the intensity changes with applied load. We observed that the twin volume fraction changes with plastic strain is sensitive to the initial texture, while the relative hardening of different deformation modes are considered as a secondary effect. We also found that the twin interior stresses were significantly smaller and consistent with the high twin back stresses in the presence of precipitates. We propose, based on a simple analytical equation, that the leading edge of the propagating twin have a Burgers vector equivalent to 100 twinning dislocations and when the propagating twin is blocked by a precipitate, relatively high resolved stress is required for bowing the twin dislocation and hence the propagation of the twin occurs by the dissociation of the leading edge of the twinning dislocation.

History

Journal

Acta materialia

Volume

119

Pagination

145-156

Location

Amsterdam, The Netherlands

ISSN

1359-6454

eISSN

1873-2453

Language

eng

Publication classification

C Journal article, C1 Refereed article in a scholarly journal

Copyright notice

2016, Acta Materialia

Publisher

Elsevier