Figure 7

SEM images showing fracture surface of specimens tested under (a) 1-1-1-1 and (b) 1-90-1-1 waveforms at 725°C in vacuum.
SEM images showing fracture surface of specimens tested under (a) 1-1-1-1 and (b) 1-90-1-1 waveforms at 725°C in vacuum.