Influence of the chemical composition on the β-relaxation and the mechanical behavior of LaCe-based bulk metallic glasses

The β-relaxation is attributed to the localized motion of constituent atoms in the localized regions of bulk metallic glasses (BMGs). Here, the β-relaxation behavior and the mechanical performance of a series of LaCe-based BMGs with various chemical compositions were investigated by adjusting or replacing constituent elements. For (La₄₀Ce₆₀)₆₅Al_10+xCo_25−x (x = 0, 5, 10) BMGs, prominent β-relaxation was observed, and the relaxation temperature (T_β) increased with Al content. The substitution of Co with Ni increased T_β, whereas the substitution of Co with Cu suppressed the β-relaxation. The results of compression testing at room temperature showed that once the deformation temperature was close to the activating temperature of the β-relaxation, potential shear transformation zones could be activated due to the activated atomic mobility caused by applied stress. Thus, plastic deformation could be accommodated.