Papers by Author: M. Zakaria Quadir

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Authors: Michael Ferry, Wan Qiang Xu, M. Zakaria Quadir, Nasima Afrin Zinnia, Kevin J. Laws, Nora Mateescu, Lalu Robin, Lori Bassman, Julie M. Cairney, John F. Humphreys, Adeline Albou, Julian H. Driver
Abstract: A focused ion beam (FIB) coupled with high resolution electron backscatter diffraction (EBSD) has emerged as a useful tool for generating crystallographic information in reasonably large volumes of microstructure. In principle, data generation is reasonably straightforward whereby the FIB is used as a high precision serial sectioning device for generating consecutive milled surfaces suitable for mapping by EBSD. The successive EBSD maps generated by serial sectioning are combined using various post-processing methods to generate crystallographic volumes of the microstructure. This paper provides an overview of the use of 3D-EBSD in the study of various phenomena associated with thermomechanical processing of both crystalline and semi-crystalline alloys and includes investigations on the crystallographic nature of microbands, void formation at particles, phase redistribution during plastic forming, and nucleation of recrystallization within various regions of the deformation microstructure.
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Authors: M. Zakaria Quadir, Michael Ferry, P. R. Munroe
Abstract: Lamellar bands are the primary structural features in accumulative roll bonding (ARB) of sheet metals. The structural refinement in ARB sheets occur by forming a dense distribution of lamellar band boundaries. The lamellar band boundaries initiate as low angle interfaces, parallel to the existing lamellar band boundaries, irrespective of the crystallographic orientations of the parent lamellar bands. From an extensive investigation it was found that the transverse directions across the lamellar band boundaries are rotated by an angle equal to their misorientations. Such a phenomenon is not sustained when the boundaries turn to high angle.
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Authors: M. Zakaria Quadir, Lori Bassman, O. Al-Buhamad, Michael Ferry
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Authors: O. Al-Buhamad, M. Zakaria Quadir, Michael Ferry
Abstract: A multilayered sheet composite of commercial purity Al and Al-0.3%Sc alloys was produced by accumulative roll bonding. The final sheet material consisted of 64 ultra fine grained layers, each of ~7.8mm in thickness. The as-deformed material was annealed at temperatures ranging from 250 to 350°C to study the changes in microstructure and their associated influence on mechanical properties. The as-deformed structures largely comprised of high angle grain boundaries in the Al layers and low angle grain boundaries in the Al(Sc) layers. During annealing, the structures in the Al(Sc) layers remained unaltered, whereas the Al layers recrystallized rapidly to the full layer thickness. The mechanical properties of the Al-Al(Sc) composite were measured and found to be unique in strength and ductility with annealing temperature having a significant influence on these properties.
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Authors: Delphine Retraint, M. Zakaria Quadir, Wan Qiang Xu, Laurent Waltz, Michael Ferry
Abstract: It is possible to produce a nanocrystalline, multilayered composite structure with enhanced mechanical properties by assembling three 316L surface nanostructured stainless steel plates by roll bonding. The Surface Mechanical Attrition Treatment (SMAT) was first used to generate nanocrystalline layers on the elementary plates so that their mechanical properties were improved. They were then assembled through co-rolling. A composite structure of nanocrystalline layers of high strength alternating with more ductile layers was obtained to achieve both high strength and ductility. Microscopy observations and EBSD measurements were carried out and the bonding interfaces were analysed in detail to explore the mechanisms involved during the SMAT/Co-rolling duplex process.
127
Authors: Nasima Afrin Zinnia, M. Zakaria Quadir, Lori Bassman, Julian H. Driver, A. Albou, Michael Ferry
Abstract: The crystallographic alignment of microbands in a Goss oriented single crystal was investigated by two and three dimensional electron back scatter diffraction. The microband boundaries were found to be curved instead of being perfectly flat interfaces, and the overall alignment closely matched a potential slip plane. The bumps and curved were created during subsequent deformation and, thus, deviates the microband boundaries from crystallographic nature.
101
Authors: M. Zakaria Quadir, O. Al-Buhamad, Michael Ferry
Abstract: A high-purity Al alloy and a supersaturated Al-0.3wt.% Sc alloy were accumulative roll bonded (ARB) at 200 °C to generate 0.5 mm gauge sheet consisting of 32 alternating layers of Al and Al(Sc). The material was subsequently annealed for 6h at 350 °C. The deformation and annealed microstructures were investigated using transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD). The deformation microstructure composed primarily of lamellar bands of unequal fineness with shear bands and deformation bands being additional substructural features in the Al(Sc) layers. The high strain deformation generated Al layers containing lamellar boundaries separated by a large fraction of high angle grain boundaries, thereby creating the ideal microstructure for continuous recrystallization. Annealing of the as-deformed material generated a hybrid microstructure consisting of alternating layers consisting of ~20 0m grains produced by continuous recrystallization (Al layers) and a lightly recovered substructure (Al(Sc) layers); the latter were highly resistant to recrystallization due to precipitation of nanosized Al3Sc particles during annealing.
307
Authors: K.D. Lau, M. Zakaria Quadir, Michael Ferry
Abstract: Accumulative Roll Bonding (ARB) is a severe plastic deformation technique for producing ultra-fine grain structures in sheet metal. In this investigation, the through-thickness shear strain distribution during single pass rolling of roll-bonded aluminium sheets was monitored via the deflection of an embedded scratch on the through-thickness, pre-polished surface of the material. It was found that, near the sheet surface and at its mid-thickness, rolling generated severe and moderate shearing, respectively. Such shearing was found to have a strong influence on the microstructure and crystallographic texture of the material, which was eliminated during subsequent rolling cycles. Compared to the core of a given rolled layer, both the microstructure and texture at the interface of the layers was inhomogeneous.
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Authors: Lori Bassman, Cassandra George, M. Zakaria Quadir, Nasima Afrin, Ben Yue Liu, Brian Soe, Michael Ferry
Abstract: There are two opposing theories regarding the nature of aligned dislocation boundaries generated during plastic deformation of FCC metals: (i) they are oriented along crystallographic planes, and (ii) their alignment is dictated by the macroscopic stress state during plastic deformation. 3D crystallographic orientation data were collected on a volume containing microbands in commercial purity aluminum, and 3D boundaries were reconstructed. Both types of alignment were found in local surface features.
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Authors: Michael Ferry, M. Zakaria Quadir, Nasima Afrin Zinnia, Lori Bassman, Cassandra George, Cullen Mcmahon, Wan Qiang Xu, Kevin J. Laws
Abstract: A focused ion beam (FIB) coupled with high resolution electron backscatter diffraction (EBSD) has emerged as a useful tool for generating crystallographic information in reasonably large volumes of microstructure. In principle, data generation is reasonably straightforward whereby the FIB is used as a high precision serial sectioning device for generating consecutive milled surfaces suitable for mapping by EBSD. However, there are several challenges facing the technique including the need for accurate reconstruction of the EBSD slice data and the development of methods for representing the myriad microstructural features of interest including, for example, orientation gradients arising from plastic deformation through to the structure of grains and their interfaces in both single-phase and multi-phase materials. This paper provides an overview of the use of 3D-EBSD in the study of texture development in alloys during deformation and annealing and includes an update on current research on the crystallographic nature of microbands in some body centred and face centred cubic alloys and the nucleation and growth of grains in an extra low carbon steel.
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