Misorientation Measurement of Individual Grains in Fatigue of Polycrystalline Alloys by Diffraction Contrast Tomography Using Ultrabright Synchrotron Radiation

Abstract:

A three dimensional grain mapping technique for polycrystalline materials, called X-ray diffraction contrast tomography (DCT), was developed at SPring-8, which is the brightest synchrotron radiation facility in Japan. The developed technique was applied to a commercially pure iron and austenitic stainless steel. The shape and location of grains could be determined by DCT using the apparatus in a beam line of SPring-8. To evaluate the dislocation structure in fatigue, the total misorientation of individual grains was measured by DCT. The average value of the total misorientation over one sample was increased with the number of cycles. In a grain, the change of the total misorientation was largest for primary slip plane. For austenitic stainless steel (fcc), the change of the total misorientation in fatigue was larger for planes with larger Schmid factor, while it was not depended on the Schmid factor for commercially pure iron (bcc). This different behavior must come from planer slip in fcc structure and wavy slip in bcc structure.

• Periodical: Materials Science Forum (Volume 879)
• Pages: 1355-1360
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.879.1355
• Online since: November 2016
• Authors: Yoshikazu Nakai*, Daiki Shiozawa, Ryota Nakao, Naoya Asakawa, Shoichi Kikuchi
• Keywords: Diffraction Contrast Tomography, Dislocation Structure, Fatigue Damage, Synchrotron Radiation, Total Misorientation

References

[1] S. Suresh, Fatigue of materials, Cambridge University Press, (1991).

[2] P. Gay, P.B. Hirsch, and A. Kelly, The estimation of dislocation densities in metals from X-ray data, ACTA Metallurgica, 1 (1953) 315-319.

DOI: 10.1016/0001-6160(53)90106-0

[3] S. Taira and K. Hayashi, X-Ray investigation on fatigue fracture of notched steel specimen: Observation of fatigue phenomena of annealed low-carbon steel by X-ray microbeam technique, Bulletin of Japanese Society of Mechanical Engineers, 9 (1966).

DOI: 10.1299/jsme1958.9.627

[4] S. Taira, X-ray-diffraction approach for studies on fatigue and creep, Experimental Mechanics, 13 (1973) 449-463.

DOI: 10.1007/bf02322729

[5] Y. Nakai, K. Tanaka, and T. Nakanishi, The effects of stress ratio and grain size on near-threshold fatigue crack propagation in low-carbon steel, Engineering Fracture Mechanics, 15 (1981) 291-302.

DOI: 10.1016/0013-7944(81)90062-x

[6] H. F. Poulsen, Three-dimensional X-ray diffraction microscopy. Mapping polycrystals and their dynamics, Springer Tracts in Modern Physics, Springer, Berlin, (2004).

DOI: 10.1007/978-3-540-44483-1_5

[7] B. C. Larson, W. Yang, G. E. Ice, J. D. Budai, and T. Z. Tischler, Three-dimensional X-ray structural microscopy with submicrometre resolution, Nature, 415 (2002) 887-890.

DOI: 10.1038/415887a

[8] W. Ludwig, S. Schmidt, E. M. Lauridsen and H. F. Poulsen, X-ray diffraction contrast tomography: A novel technique for three-dimensional grain mapping of polycrystals. I. Direct beam case, Journal of Applied Crystallography, 41, (2008) 302-309.

DOI: 10.1107/s0021889808001684

[9] D. Shiozawa, Y. Nakai, R. Miura, N. Masada, S. Matsuda, and R. Nakao, 4D evaluation of grain shape and fatigue damage of individual grains in polycrystalline alloys by diffraction contrast tomography using ultrabright synchrotron radiation, Int. J. Fatigue, 82 (2016).

DOI: 10.1016/j.ijfatigue.2015.07.014

[10] R. Gordon, R. Bender, and G. T. Herman, Algebraic reconstruction techniques (ART) for three-dimensional electron microscopy and X-ray photography, J. Theor. Biol., 29 (1970) 471-481.

DOI: 10.1016/0022-5193(70)90109-8

[11] D. Shiozawa, Y. Nakai, H. Nosho, Observation of 3D shape and propagation mode transition of fatigue cracks in Ti-6Al-4V under cyclic torsion using CT imaging with ultra-bright synchrotron radiation, International Journal of Fatigue, 58, (2014).

DOI: 10.1016/j.ijfatigue.2013.02.018

[12] T. Makino, Y. Neishi, D. Shiozawa, Y. Fukuda , K. Kajiwara and Y. Nakai, Evaluation of rolling contact fatigue crack path in high strength steel with artificial defects, International Journal of Fatigue, 68, (2014) 168-177.

DOI: 10.1016/j.ijfatigue.2014.05.006

[13] D. Shiozawa, T. Makino, Y. Neishi, and Y. Nakai, Observation of rolling contact fatigue cracks by laminography using ultra-bright synchrotron radiation, Procedia Mat. Sci. 3 (2014) 154-164.

DOI: 10.1016/j.mspro.2014.06.030

[14] Y. Nakai and D. Shiozawa, Initiation and growth of pits and cracks in corrosion fatigue for high strength aluminium alloy observed by micro computed-tomography using ultra-bright synchrotron radiation, Applied Mechanics and Materials, 83 (2011).

DOI: 10.4028/www.scientific.net/amm.83.162

[15] Y. Nakai and T. Kusukawa, Quantitative evaluation of slip-band growth and crack initiation in fatigue of 70-30 brass by means of atomic-force microscopy, Trans. Japan Soc. Mech. Eng (A), 67 (2001) 476-482.

DOI: 10.1299/kikaia.67.476

[16] Y. Nakai, Evaluation of fatigue damage and fatigue crack initiation process by means of atomic-force microscopy, Materials Science Research International, 7 (2001) 73-81.

DOI: 10.2472/jsms.50.6appendix_73

[17] K. Tanaka, Y. Nakai, and M. Maekawa, Microscopic study of fatigue crack initiation and early propagation in smooth specimen of low carbon steel, Journal of the Society of Materials Science, Japan, 31(1982) 376-382.