In microforming scaling down the size of the process while the grain size is kept relatively constant usually results in inhomogeneous deformation. In most works, the inhomogeneous deformation of miniaturized samples is presented and evaluated by microstructure analyses of the deformed grains. However, in certain microforming processes, such as microextrusion, where the final texture of the conventional macro size samples is well known, texture analyses can provide useful information about the deformation. In our past research, extrusion experiments were performed to produce sub-millimeter sized pins having a base diameter of 0.76 mm and an extruded diameter of 0.57 mm. Curvature of differing degrees and directions was observed in workpieces with a coarse grain size of 211 μm. However, a similar effect did not occur in workpieces with a fine grain size of 32 μm. Microstructure analyses showed that when the sample size approaches the grain size, the deformation becomes inhomogeneous and the properties of individual grains can dominate the overall deformation of their cross-sections. Moreover, microhardness measurements revealed that deformation size effects are present and as a result the coarse grained pins strain hardened more than the fine grained pins during microextrusion. This result along with microstructure analyses suggested that the coarse grains in the central region possibly undergo more shear deformation. In this paper, X-ray texture analyses of the pins were performed to validate that there is penetration of shear deformation into the central regions of the coarse grained pins. Also, the texture analyses point to the possibility that the deformation in the curved region of the coarse grained pins is not axially symmetric which causes the curvature observed.
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Characterization and Investigation of Deformation During Microextrusion Using X-Ray Texture Analyses
Parasız, SA, Kinsey, BL, Krishnan, N, & Cao, J. "Characterization and Investigation of Deformation During Microextrusion Using X-Ray Texture Analyses." Proceedings of the ASME 2007 International Manufacturing Science and Engineering Conference. ASME 2007 International Manufacturing Science and Engineering Conference. Atlanta, Georgia, USA. October 15–18, 2007. pp. 911-919. ASME. https://doi.org/10.1115/MSEC2007-31107
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