Texture Evolution and Associated Nucleation and Growth Mechanisms during Annealing of a Zr Alloy

Abstract

The evolution of the crystallographic texture in a Zr-2Hf alloy has been followed during deformation, primary recrystallization, and subsequent normal grain growth. The rolling textures (from 50 to 90 pct strain) are constituted of two partial orientation fibers, D f = {hkil}h10 " 10i and R f = {hkil}h11 " 20i; along which the two main orientations are the socalled ''tilted'' {0001}h10 " 10i and tilted {0001}h11 " 20i texture components for which the {0001} poles are approximately 25 deg away from the specimen normal direction (ND). A decrease in the intensity of the D f fiber and a continuous increase in the intensity of the R f fiber take place during primary recrystallization and normal grain growth. An analysis of the neutron diffraction line profiles reveals a stored energy (SE) difference between the main orientations of these two texture fibers after deformation. These observations as well as some considerations about the possible active deformation systems and some partial observations of the nucleation and growth states allow us to propose possible mechanisms to explain the observed texture evolution.

Structure of grain boundaries with 30°[0 0 0 1] misorientation in dynamically recrystallized magnesium alloys

“…30°[0 0 0 1] misorientation has been repeatedly observed with an intensity peak in the distribution of the misorientation angle [5][6][7][8][9][10][11][12][13][14][15][16] in dynamically recrystallized microstructures of Mg and Mg alloys. This type of GBs appears to be common in HCP metals, for example, it was also observed in Zr [17]. Because of the special misorientation angle, the 30°[0 0 0 1] GBs have oftentimes been attributed to the formation of the coincident site lattice (CSL) [6] that is close to R13a with a misorientation angle close to 30°.…”

Investigation of SIBM driven recrystallization in alpha Zirconium based on EBSD data and Monte Carlo modeling

“…tilted{0001}<2-1-10> is formed, despite the fact that recrystallization is not complete, while it is often underlined that such a component should appear as a result of an additional grain growth process [2,3]. Therefore, other mechanisms responsible for such a development of recrystallization texture should be expected in the considered case.…”

“…It is noted that recrystallization kinetics depends on the direction of the applied compression -the recrystallized area fraction is higher in the S sample: 0.7 in comparison to 0.58 in the H sample. However, in both samples recrystallized grains have a similar size -160 µm 2 An example EBSD map recrystallized partition extracted from the annealed state of H sample strained by 17% is shown in figure 4. It can be underlined that strain-free grains tend to gather in cluster-like structures instead of being randomly distributed in terms of spatial location.…”

“…The presented description of possible recrystallization mechanisms has been refined further based on examination of rolled Zr-2Hf alloy (50% and 90% of strain) [2]. Taking into account an evaluation of stored energy and detailed analysis of texture evolution during annealing, it has been noted that strain induced boundary migration (SIBM) can play an important role, as the process responsible for growth of sub-grains formed inside grains during recovery.…”

Comparison of 2 methodologies developed for the determination of residual stresses through X-ray diffraction: application to a textured hcp titanium alloy

“…2. The texture is typical from rolled and annealed titanium, and is composed of two main texture components, which are the socalled tilted 0001 〈112 0〉 and tilted 0001 〈11 00〉 orientations [10]. This texture statistically respects the orthotropic symmetry arising from the rolling process and is far from isotropy (the maximum is larger than 6 for the {0002} pole figure).…”