The dynamic relaxation process and stress relaxation are important experimental methods to reflect the microstructure of materials, which are closely related to the diffusion, the glass transition phenomenon and the microstructural heterogeneity. It is of great significance to explore the relationship between them. In the current research, the <i>β</i>-relaxation characteristics and stress relaxation behaviors of bulk and ribbon samples obtained by different cooling rates are systematically investigated using the typical La-based amorphous alloys as model systems. The experimental results demonstrated that the cooling rate is an important parameter for controlling the energy state of the glass system, which in turn affects its physical and mechanical properties. Based on the dynamical mechanical spectra, the larger the cooling rate, the greater the low-temperature internal friction, the smaller the beta relaxation activation energy according to Arrhenius calculations, and the greater the broadening of the beta relaxation behavior in the temperature spectra, suggesting that the higher cooling rate leads to greater atomic mobility and a high degree of heterogeneity in the microstructure. Thermodynamic analysis is used to study the slow process of thermal activation and the fast process driven by stress. At low temperature, the activation volume of the strip sample is larger than that of the bulk sample, and the activation volume value of the two samples is almost the same as that of the cooling rate only affects the <i>β</i> relaxation stage, but has little effect on the <i>α</i> relaxation, which is consistent with the conclusion that the stress relaxation and <i>β</i> relaxation behavior are related to the structural non-uniformity of the amorphous alloy. Based on stress relaxation tests, the characteristic time of deformation decreases at higher cooling rates, the normalized stress decay is larger, it is easier to deform under an applied force field, and the deformation units are more likely to activate to accommodate structural deformation. The correlation between stress relaxation and β relaxation of amorphous alloys is further confirmed, and the proportion of liquid-like region is proportional to the relaxation mode spectrum, which also shows that β relaxation and stress relaxation are consistent. Finally, by calculating relaxation enthalpy △<i>H</i><sub>rel</sub>, the variation of microstructure heterogeneity with cooling rate is experimentally verified. The research sheds new light on further clarifying the association between <i>β</i> relaxation, deformation and microstructural heterogeneity of the amorphous alloy.
