Issue34

S. Takaya et alii, Frattura ed Integrità Strutturale, 34 (2015) 355-361; DOI: 10.3221/IGF-ESIS.34.39 359 primary twin planes are largely different from 80º, and twining was not observed in the area “III”, indicating those parallel lines were formed due to basal slip operation. Figure 6 : Schematic illustration of angle analysis; (a) Coordinates, (b) Definition of angle, α, (c) Definition of Plus or minus sign of α . Slip plane Slip direction Schmid factor Slip angle, α Basal slip (0001) [11-20] 0.38 -86.74 [2-1-10] -0.02 [1-210] -0.40 Primary twin (01-12) [01-1-1] -0.19 -89.18 (10-12) [10-1-1] -0.31 -51.89 (1-102) [1-10-1] 0.33 -33.51 (0-112) [0-11-1] 0.25 -77.52 (-1012) [-101-1] -0.34 39.57 (-1102) [-110-1] 0.30 55.16 Table 1 : Schmid factors and slip angles calculated in the area “I” in Fig.4(a). Slip plane Slip direction Schmid factor Slip angle, α Basal slip (0001) [11-20] -0.26 75.73 [2-1-10] -0.15 [1-210] 0.11 Primary twin (01-12) [01-1-1] -0.45 33.48 (10-12) [10-1-1] -0.45 41.87 (1-102) [1-10-1] 0.46 -85.29 (0-112) [0-11-1] 0.42 -60.89 (-1012) [-101-1] -0.42 -74.55 (-1102) [-110-1] 0.46 60.02 Table 2 : Schmid factors and slip angles calculated in the area “III” in Fig.4(c). (a) (b) (c) Fracture surface Fracture surface