Study on Evaluation of Ductile Damage of Aluminum Single Crystal Using Synchrotron White X-Ray
Jun-ichi SHIBANO, Minoru KISO, Kentaro KAJIWARA, Takahisa SHOBU, Setsuo MIURA and Michiaki KOBAYASHI
Abstract:The ductile damage progress of the FCC single crystal was verified by the profile analysis using the white X-ray obtained in BL28B2 beam-line of SPring-8. In this study, an aluminum single crystal of the purity 6N was used as a specimen prepared in the I-type geometry for tensile test. The notch was introduced into one side of the center of a parallel part of the specimen by wire electric discharge machining. White X-ray, which has 200 microns in height and 100 microns in width, was incident into the specimen on the Bragg angle Į of 3 degrees in the horizontal plane using energy dispersive X-ray diffraction technique. The specimen was deformed by elongation along crystal orientation [001], and the diffraction profile of the white X-ray which penetrated it was analyzed. In profile analysis, the instrumental function was defined in consideration both of a divergence by a slit and a response function peculiar to an energy dispersive method. The Gauss component of integral breadth related to non-uniform strain and the Cauchy component of integral breadth related to crystallite size were determined by removing the broadening by the instrumental function from the diffraction profile of white X-ray. As a result, in 1.1% of applied strain, increase of the lattice strain was observed in the direction of about 45 degrees of slant from the notch bottom. However, the Gauss component and the Cauchy component of the integral breadth did not indicate the distinct tendency. In 2.2% of applied strain, the lattice strain reduced in the direction of about 45 degrees of slant from the notch bottom. Non-uniform strain and dislocation density decreased similarly. On the other hand, the development of crystallite was estimated in the area due to the increasing of the Cauchy component. The characteristic of the ductile damage progress near the notch of the aluminum single crystal which has crystal orientation [001] along the tensile direction was confirmed by this method. Key Words:Profile analysis, Instrumental function, Ductile damage, Non-uniform strain, Single crystal, White X-ray