Internal Residual Stress Measurements of Tensile-Deformed Aluminum Single Crystals Using Synchrotron Radiation

Abstract

The changes in the microstructures associated with plastic deformation and strain/stress were measured using the strain scanning method with hard synchrotron radiation. Aluminum single crystals tensile-deformed along the <111> direction exhibit a macroscopically uniform multiple-slip without deformation bands. Plastic deformation has an insignificant effect on lattice spacing, and is likely responsible for the relatively uniform distribution of internal stress with a small absolute value. With regard to the crystallographic orientation, the rocking curves in the as-annealed sample differed with position, strongly suggesting that mosaic structures exist in a single crystal. In the 8% tensile-deformed sample, mosaic blocks are divided into smaller size. The increase in the number of mosaic blocks with deformation causes broadening the rocking curve and FWHM of the profile.

Tensile deformation and recrystallization of aluminum single crystals with sub-grained structures studied by synchrotron X-ray radiation

“…The central portion had a cylindrical shape, 5 mm in diameter and 20-mm long. We prepared two samples and labeled them samples C and D, following samples A and B used in our previous study (Shiro et al, 2013).…”

“…The diffraction profile obtained by the q-2q scan was used to calculate the strain from its peak position. Further details regarding the strain-scanning method are described in our previous paper (Shiro et al, 2013). Both samples C and D were measured at three stages: the pre-deformation; post-deformation; and post-annealing stages.…”

“…As in our previous paper (Shiro et al, 2013), the strain-scanning method was applied to calculate the residual strains in deformed samples C and D. The strains were very small, i.e., 1×10 -4 and 0.3×10 -4 for samples C and D, respectively. These values correspond to residual stress of about 10 MPa at most, which is much lower than the flow stress of 60 MPa during tensile deformation.…”

“…Transmission electron microscopy has also been applied to observe the dislocation microstructures in deformed samples. However, there had been little effort to non-destructively observe the interior of samples until we first carried out experiments on <111>-oriented Al single crystals using synchrotron X-ray radiation at SPring-8 (Shiro et al, 2013). We found that Al single crystals with fine mosaic structures were imperfect from the crystallographic point of view.…”

<i>In situ</i> synchrotron radiation observation of deformation and annealing processes of aluminum single crystal

“…To observe the interior of the samples, destructive observation with transmission electron microscopy was necessary. We first carried out non-destructive interior observation of Al 〈111〉-oriented crystals using synchrotron radiation X-ray at SPring-8 (Shiro et al, 2013) and found that the Al crystals were not perfect but rather were composed of several subgrains with small orientation differences, which could not be removed by pre-deformation annealing. The samples were deformed in tension and subsequently annealed to evaluate the crystallinity of deformed microstructures and recrystallized grains (Shiro et al, 2020).…”