Grain Boundary Engineering Basic Knowledge Part 2 Structuredependent

　Grain Boundary Engineering (　Basic Knowledge ： Part 2 ) Structure-dependent Boundary Properties. 1. Mechanical Properties Roles in Deformation and Fracture 2. Chemical Properties, Potential Sites of Chemical Reactions 3. Electrical Properties　(Electron Scattering ) 4. Magnetic Properties ( Domain Wall Motion ） 5. Thermal Properties Paths for migration of atoms, vacancies. )

SEM-Electron Channelling Pattern (ECP)s from Grains with Different Orientations in Fe-6. %mass%Si Ribbon.

Recent Technique for the Characterization of Grain Boundary Microstructure Orientation Imaging Microscopy (OIM) B. Adams, S. I. Wright and K. Kunze, Metal. Trans. , 24 A (1993), 819 -831. FEＧ-SEM/EBSD/OIM ( Hitachi S-4200 )

OIM Analysis of Grain Boundary Microstructure in b-Si. C Polycrystal (a) SEM Observation (b) Grain Orientation , Grain Boundary Character Distribution (GBCD) (S. Tsurekawa, T. Watanabe, H. Watanabe and T. Tamari, Key Eng. Mater. , Vol. 247 (2003), 327 ~330. )

[100] tilt (a) [110] tilt (b) Variations in Grain Boundary Energy for Symmetric Tilt Grain Boundaries in Al Bicrystal. ( G. Hasson, J. –Y. Boos, I. Herbeuval, M. Biscondi and C. Goux : Surface Science, 31 (1972), 115 -137. ) Relative Grain Boundary Energy ggb / gsl = 2 cos(a/2) as a Function of Misorientation, G for Al, a) <110>Twist, c) <100>-Tilt, and d) <100>-Twist Grain Boundary. (A. Otsuki, Trans. JIM. , Suppl. , 27 (1986), 789~796. )

Effects of Grain Boundary Structure on Grain Boundary Migration in Pb-Sn Alloy bicrystals K. T. Aust and J. W. Rutter, Trans. Met. Soc. AIME. , 215 (1959), 119 -127.

Misorientation Dependence of Grain Boundary Hardness in <100> Tilt Niobium Bicrystals. (Y. T. Chou, B. C. Cai, A. D. Romig, Jr. and L. S. Lin, Phil. Mag. A, 47 (1983), 363 -368. )

Deformation of Grain Boundary in Bicrystal and Tricrystal Stress-strain Curves of <100> Bicrystals having 4°, 14° and 37° Boundaries and Component Single Crystals. (S. MIURA and Y. SAEKI, Acta Metallugica. 26 (1978), 93 -101. ) SEM Micrographs Showing (a) the Surface of Tricrystal Specimen Deformed at 1073 K under 6 MPa for 200 h and (b) the Enlarged View of Triple Junction. (S. Miura, T. Okada, S. Onaka and S. Hashimoto, Colloq. de Phys. , C 1, 51 (1990), C 1 -587 -592. )

R S 13 Interactions of Lattice Dislocations with Grain Boundaries of Different Types ; (a) a Random Boundary (Grain Boundary 1), (b) a slightly off. S 13 b Coincidence Boundary (Grain Boundary 2) in the Specimen Crept up to 1. 3% Elongation at Tensile Stress of 5 MPa and 600 K. (H. Kokawa, T. Watanabe and S. Karashima, J. Mater. Sci. , 18 (1983), 1183 -1194. )

Grain Boundary Sliding in <1010>Tilt Zinc Bicrystals T.

T. Watanabe、S. Kimura and S. Karashima; Phi. Mag. , 49(1984), 845 -864.

Grain Boundary Structural Transformation at High Temperatures.

Soap Bubble Mode of Grain Boundary Structural Transformation

Misorientation Dependence of Fracture Stress in Molybdenum Bicrystals with <110> Symmetric Tilt Boundaries. ( Tsurekawa, Tanaka and Yoshinaga, Mater. Sci. Eng. , A 176 (1994), 341. )

Effects of Boundary Misorientation Angle on Fracture Stress and Strain in Bicrystal S 3 Misorientation Dependence of Fracture Stress and Strain in <1010> Tilt and <1010> Twist Zinc Bicrystals. (T. Watanabe, S. Sima and S. Karashima : Embrittlement by liquid and solid metals, Met. Soc. AIME, (1984), 161 -172) S 11 Misorientation Dependence of Fracture Stress and Strain in Cu-Bi <110> Tilt Bicrystal. ( H. Miura, T. Yoshida, T. Sakai, M. Kato and T. Mori, J. Jpn. Inst. Metals, 57 (1993), 479 -485)

Fracture Energy gf , for Ideal Grain Boundary Fracture, gf = 2 gs – ggb (1) gs : Surface Energy ggb : Grain Boundary Energy Fracture Energy gf , for Grain Boundary Fracture involving Plastic Deformation, gf = 2 gs – ggb + gpl : Plastic Strain Energy (2)