FRACTURE OF Zr56Ni24Al20 AMORPHOUS ALLOYS AT ULTRALOW TEMPERATURES

Abstract

We observed the failure surface of Zr 56 Ni 24 Al 20 amorphous ribbon samples tested in uniaxial tension in low temperature interval up to 0.5 K. Shear ductile failure manifestations were obviously present. Metallic glasses are usually deformed by the shear fracture with obvious shear bands and show little plasticity before the final fracture. At low temperatures the chevron pattern morphology is rarely present too. The occurence of chevrons is connected with decreasing of the fracture stress. Analysis of fracture morphology revealed that dominantly chevron morphology is present and that the failure of this amorphous material initiates at low temperatures at geometrical imperfections of ribbons. These failures are often presented as a premature failure.