13th International Conference on Fracture June 16–21, 2013, Beijing, China -6- cup and cone fracture at ~45° to the tensile axis, and were heavily sheared. The fracture surfaces of specimens tested at -1200 mVAg/AgCl and -1400 mVAg/AgCl also showed obvious ductility, presenting a cup and cone fracture with a large secondary crack about 170 µm in size and small secondary cracks less than 150 µm in size completely surrounded by dimples. Figure 6. Specimen S950.02 tested in 0.1 M Na2SO4, pH 2 at -950 mVAg/AgCl at 0.02 MPa s -1: (a) overview of the fracture surface, (b) a magnified view of region A, and (c) a magnification of region B. Figure 7. Specimen S1550.02 tested in 0.1 M Na2SO4, pH 2 at -1550 mVAg/AgCl at 0.02 MPa s -1: (a) an overview of the fracture surface, and (b) a detailed view in region C. Fig. 7(a) presents the fracture surface of specimen S1550.02 tested at -1550 mVAg/AgCl at a rate of 0.02 MPa s-1. Region A of the fracture surface, similar to that shown in Fig. 6(b), was mainly MVC with some secondary cracks up to 550 µm. These secondary cracks surrounded by dimples were (a) (b) (c) A B B (a) (b) A B B C
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