The image on the left is a time lapse animation of a crack initiating and growing from a notch in super-elastic nitinol.

It is one of the many results obtained using our custom phase shifting moire interferometer during dynamic testing.

You download our paper Fatigue Crack Initiation in Superelastic Nitinol published in ASTM 1559 STP Fatigue and Fracture of Medical Metallic Materials and Devices, Volume 3.