The correlation between structural characteristics and plasticity mediated by shear transformation zone size in amorphous alloys

In this study, the correlations between structural characteristics, shear transformation zone (STZ) size and shear-band mediated plasticity were systematically investigated in crystalline-layer confined amorphous (CLCA) NiW alloy films. In these films, the structural states with or without distributed structural defects – the so-called nano shear bands (NSBs) – could be regulated by thermal treatment. It was found that NSBs positively impacted the STZ size obtained by strain rate sensitivity (SRS) method (known as engineering STZ size), which actually reflected the combined size of the connected STZs and was proportional to the plasticity of amorphous alloys. Whilst, NSBs were unprevailing in case of the statistically determined STZ size. This was owing to the fact that such a size was closer to the real STZ size that was independent of the structural state and plasticity of amorphous alloys. The findings of the present work enabled one to elucidate the underlying mechanism of the discrepancy of STZ size, as well as to establish its relationship with structural characteristics and plasticity of amorphous alloys.