Environment Assisted Crack Propagation in Zr-Based Bulk Metallic Glass
Yoshikazu NAKAI and Yasunori YOSHIOKA
Abstract:Crack propagation tests on a bulk metallic glass, Zr55Cu30Ni5Al10, were conducted either in aqueous sodium chloride (NaCl) solutions or high purity water under sinusoidal cyclic loading or sustained loading. Although the crack growth rate in high purity water was almost identical to that in air, the rate in NaCl solution was much higher than that in air even in a very low concentration of NaCl such as 0.01%. In 3.5% NaCl solution, the time-based crack propagation rate during cyclic loading, da/dt, was determined by the maximum stress intensity factor, Kmax, but was almost independent of the loading frequency and the stress ratio, and the rate was close to that of environment-assisted cracking under a sustained load. Key Words:Bulk metallic glass, Fatigue crack propagation, Stresscorrosion cracking, Fractography