Nanoscale ripples on the compressive fracture surface of a bulk metallic glass with microscale crystals

Some periodic and straight strips with about 60 nm spacing were observed on the compressive fracture surface of Ni42Cu5Ti20Zr21.5Al8Si3.5 bulk metallic glass (BMG) rods containing minor microscale crystals. The characteristic difference between amorphous matrix and microscale crystals also reveal why periodic corrugations could not be observed on the fracture surface of metal crystals. The dynamic crack instability may be explained by the interaction of the propagating crack and the internal micro-cracks. This kind of periodic morphologies showed in-plane feature, which may be attributed to the non-intense interaction between dynamic crack and micro-crack.