Please use this identifier to cite or link to this item: https://apo.ansto.gov.au/dspace/handle/10238/5484
Title: Twinning-detwinning behavior during fatigue-crack propagation in a wrought magnesium alloy AZ31B
Authors: Wu, W
Lee, SY
Paradowska, AM
Gao, Y
Liaw, PK
Keywords: Neutron diffraction
Neutrons
Alloys
Magnetism
Stresses
Twinning
Fatigue
Growth
Strains
Deformation
Texture
Anisotropy
Metals
Issue Date: 30-Oct-2012
Publisher: Elsevier Science SA
Citation: Wu, W., Lee, S. Y., Paradowska, A. M., Gao, Y., & Liaw, P. K. (2012). Twinning-detwinning behavior during fatigue-crack propagation in a wrought magnesium alloy AZ31B. Materials Science & Engineering A-Structural Materials Properties Microstructure & Processing, 556, 278-286. doi:10.1016/j.msea.2012.06.088
Abstract: In-situ neutron diffraction was used to investigate the twinning and detwinning behavior during fatigue-crack propagation on a wrought magnesium alloy, AZ31B, compact-tension specimen, where fatigue loading was applied parallel to the plate normal. Reversible twinning and detwinning characteristics were observed as a function of the distance from the crack tip. While twinning was activated above a certain critical stress value, detwinning occurred immediately upon unloading. It is thought that the development of compressive residual stresses generated around the crack tip during unloading is responsible for the detwinning behavior. Neutron bulk texture measurements were performed at several locations away from the crack tip (i.e. locations behind, right in front of, and far away from the crack tip) to quantitatively examine the volume fraction of {10.2}< 10.1 > extension twins in the vicinity of the crack tip. The texture analyses demonstrated that the texture in the fatigue-wake region did not change significantly, compared to that in the undeformed region far away from the crack tip, and approximately 11% of the residual twins were left behind the crack tip. The current results reveal that the reversible twinning and detwinning are the dominant deformation mechanisms for the studied material subjected to cyclic loading, and only a small amount of residual twins remain after the crack propagation. The spatial distribution of twinning/detwinning transitions correlates well with our previous predictions of the stress fields in the vicinity of a fatigue crack tip. © 2012, Elsevier Ltd.
Gov't Doc #: 5138
URI: http://dx.doi.org/10.1016/j.msea.2012.06.088
http://apo.ansto.gov.au/dspace/handle/10238/5484
ISSN: 0921-5093
Appears in Collections:Journal Articles

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