Effect of nanocrystalline dispersion on fatigue in a Zr-based bulk metallic glass

A nano-scale crystal (NC) dispersed bulk metallic glass has both high tensile strength and high ductility. The new alloy is therefore expected as a candidate of high-strength structural materials in machines and structures. However, fatigue life properties in the NC bulk glass has not been examined. In this report, effects of the nanocrystalline dispersion on fatigue was studied in a NC glassy alloy Zr55Al10Cu30Ni5 (at%). Fatigue ratio, fatigue limit sigma(w)/tensile strength sigma(B), in the NC bulk glass was estimated to be about 0.13. The value was 3 times larger than that of single phase bulk metallic glasses with the same composition reported in the literature. It is considered that the inhibition of the slip initiation and growth was induced by the nanocrystal dispersion and it increased the sigma(w).