Finite element (FE) analysis was used to simulate the strain history of an α-uranium foil during cold straight-rolling, with the sheet modeled as an isotropic elastoplastic continuum. The resulting strain history was then used as input for a viscoplastic self-consistent (VPSC) polycrystal plasticity model to simulate crystallographic texture evolution. Mid-plane textures predicted via the combined FE→VPSC approach show alignment of the (010) poles along the rolling direction (RD), and the (001) poles along the normal direction (ND) with a symmetric splitting along RD. The surface texture is similar to that of the mid-plane, but with a shear-induced asymmetry that favors one of the RD split features of the (001) pole figure. Both the mid-plane and surface textures predicted by the FE→VPSC approach agree with published experimental results for cold straight-rolled α-uranium plates, as well as predictions made by a more computationally intensive full-field crystal plasticity based finite element model. α-uranium foils produced by cold-rolling must typically undergo a recrystallization anneal to restore ductility prior to their final application, resulting in significant texture evolution from the cold-rolled plate deformation texture. Using the texture measured from a foil in the final recrystallized state, coefficients of thermal expansion and the elastic stiffness tensors were calculated using a thermo-elastic self-consistent model, and the anisotropic yield loci and flow curves along the RD, TD, and ND were predicted using the VPSC code.

The a-phase transformation kinetics of as-cast U - 8 wt% Mo below the eutectoid temperature have been established by in situ neutron diffraction. alpha-phase weight fraction data acquired through Rietveld refinement at five different isothermal hold temperatures can be modeled accurately utilizing a simple Johnson-Mehl-Avrami-Kolmogorov impingement-based theory, and the results are validated by a corresponding evolution in the g-phase lattice parameter during transformation that follows Vegard's law. Neutron diffraction data is used to produce a detailed Time-Temperature-Transformation diagram that improves upon inconsistencies in the current literature, exhibiting a minimum transformation start time of 40 min at temperatures between 500 degrees C and 510 degrees C. The transformation kinetics of U - 8 wt% Mo can vary significantly from as-cast conditions after extensive heat treatments, due to homogenization of the typical dendritic microstructure which possesses non-negligible solute segregation. (C) 2016 Elsevier B.V. All rights reserved.

Magnesium alloy tubes offer an attractive combination of strength and density. However, their poor crushing behavior under axial loads has prevented their use in crash-sensitive automotive structures such as crush rails. A combination of alloy selection, strain path design, and texture control were employed in an attempt to enhance the mechanical behavior of extruded Mg tubes. C-channel extrusion, porthole-die extrusion, and seamless tube extrusion over a mandrel were all explored. Mandrel extrusion was confirmed to produce tubes ideal for later axial crush tests, as there was no weld or extrusion seam to act as a source of weakness. Crush testing of the tubes revealed that conventional alloy, AZ31B, exhibited premature fracture prior to folding. Novel alloy, ZEK100, which exhibits slightly higher ductility than AZ31B, still exhibits poor folding behavior. The crush behavior of the Mg alloy tubes is discussed in terms of their crystallographic texture.

Hand portability of non-contact optical profilometers represents a significant technological breakthrough for wide-area industrial processes such as grit blasting, capable of replacing mechanical styluses and providing real time assessment of surface roughness without damaging sampled areas. This paper demonstrates the possibility of building depth from defocus profilometers using off the shelf components, allowing for improved portability, affordability, and customization compared to similar table-top commercial products. An outlined demonstration device is proven to be capable of matching the performance of an ISO/NIST standardized mechanical profilometer for isotropic rough surfaces in the 2–10 μm Ra range with R2 > 0.96, and important considerations for each component of the assembly are addressed in detail. A prototype for a next generation liquid-lens based depth from defocus optical profilometer is also presented along with the technological obstacles found to be associated with such devices.

This chapter contains sections titled: Introduction Extrusion Experiments Computational Method Results of Finite Element Analysis Results of Deformation Texture Predictions Conclusions Acknowledgements