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In-situ X-ray diffraction studies of slip and twinning in the presence of precipitates in AZ91 alloy
journal contribution
posted on 2016-10-15, 00:00 authored by Sitarama KadaSitarama Kada, Peter LynchPeter Lynch, J A Kimpton, Matthew BarnettMatthew BarnettThe 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 materialiaVolume
119Pagination
145 - 156Publisher
ElsevierLocation
Amsterdam, The NetherlandsPublisher DOI
ISSN
1359-6454eISSN
1873-2453Language
engPublication classification
C Journal article; C1 Refereed article in a scholarly journalCopyright notice
2016, Acta MaterialiaUsage metrics
Categories
Keywords
insitu X-ray diffractionmagnesiumprecipitatestwinningbackstressScience & TechnologyTechnologyMaterials Science, MultidisciplinaryMetallurgy & Metallurgical EngineeringMaterials ScienceNEUTRON-DIFFRACTIONMAGNESIUM ALLOYDEFORMATION TWINSMGBEHAVIORALDISTRIBUTIONSPOLYCRYSTALNUCLEATIONRESOLUTIONMechanical EngineeringCondensed Matter Physics
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