Intergranular Strain Evolution in a Zircaloy-4 Alloy with Basketweave Morphology

Abstract

A Zircaloy-4 alloy with Widmansta¨tten-Basketweave microstructure has been used to study the deformation behavior at the grain level. The evolution of internal strain and bulk texture is investigated using neutron diffraction and conventional microscopic techniques. The macroscopic behavior and intergranular strain development, parallel and perpendicular to the loading direction, were measured in situ during uniaxial tensile loading. It was observed that twinning plays a major role in both microstructural changes and polycrystalline plasticity.

Characterization of a grain size refinement process in cast uranium

“…The deep penetration capability of neutrons into most metallic materials makes neutron diffraction a powerful tool for stress evolution, texture changes, and phase transformation studies [10,12]. Measurement of residual strain in cast uranium welds and its challenges were discussed recently by Brown et al [13].…”

“…Residual strains can also occur on the scale of the grain size, where some grains with particular crystallographic orientations deform plastically under a given stress, whereas others deform elastically. When the load is removed and the grains elastically recover, some grains are left under residual tension and others under residual compression [8][9][10][11]. Nonetheless, it is important, from a practical point of view, to know if the developed residual strains are released by a subsequent stress relief annealing treatment, employed also for grain recrystallization.…”

Hydride-Phase Formation and its Influence on Fatigue Crack Propagation Behavior in a Zircaloy-4 Alloy

“…The schematic hexagonal unit cells in Figure 3(c) show the local crystallographic orientation of several variants out of the 12 possible variants. [15] Two pole figures obtained from the EBSD maps are presented in Figure 3(e). The black circle in the basal 0001 pole figure is associated with two a variants in the material (the pink variant that runs from lower left to upper right and the orange variant that runs from upper left to lower right in Figure 3(c)).…”

“…The high penetration of thermal neutrons through engineering materials, such as steel, aluminum, or zirconium, makes neutron diffraction an excellent nondestructive technique to measure the elastic lattice strain response to external factors (e.g., stresses and hydrogenrich environments). [12][13][14][15][16] In this article, hydride phase formation and its influence on FCG behavior in a Zircaloy-4 alloy will be presented and discussed for three different cases, representing three different specimen histories. These cases correspond to the zircaloy in the as-received condition (case 1), to the homogenous distribution of hydrides in the bulk (case 2), and finally, to the inhomogeneous distribution of hydrides as a result of the existence of a crack prior to hydrogen charging (case 3).…”

Thermomechanical Response of Polycrystalline alpha-Uranium

“…This approach is commonly accepted in materials with strong residual stresses [44]. The same protocol is employed in the simulation tool described below, such that the comparison between model and experiment is consistent.…”