(a) X-ray diffraction transmission-mode image of the crack after the second heating cycle viewed from the back side through the sample, taken at room temperature. Around the tip of the initial crack and the lateral crack tip, many dislocations and slip bands have been generated. (b) Interference contrast microscopy image from the back side with cracks C1, C2 and C3 visible. Surface steps around the tips of cracks C2 and C3 are traces of the slip bands in Fig. 4(a). (c) Interference contrast microscopy image of the front side of the same sample (mirrored). Cracks C2 and C3 are visible and the surfaces steps correspond to the slip bands in Fig. 4(a). The arrow on top indicates the position of indentation.