Probing microstructural heterogeneity of La-based amorphous alloy under versatile mechanical stimuli

Abstract

The intrinsic structural heterogeneities of amorphous alloys are closely connected to the thermodynamics and dynamical behavior, such as relaxation/crystallization, glass transition and plastic deformation. However, the structural information is submerged into the meta-stable disordered long-range structure, which made it very difficult to explore the structural heterogeneities of amorphous alloys. A mechanical excitation factor is not sufficient to effectively describe the heterogeneity of the microstructure in amorphous alloys, particularly the correlation between structure and dynamics. To explore the essence of the structure in amorphous alloys, it is necessary to consider the different mechanical stimuli. La<sub>62</sub>Cu<sub>12</sub>Ni<sub>12</sub>Al<sub>14</sub> amorphous alloy was selected as model system, dynamic mechanical processes were probed by dynamic mechanical analysis (DMA). The contributions of a relaxation and b relaxation processes were described in the framework of the quasi-point defects theory. Based on the quasi-point defect theory, the α-relaxation and β relaxation in the La-based amorphous alloy were separated. Tensile strain rate jump measurements were conducted to study the high temperature rheological behavior of amorphous alloy. The contributions of elasticity, anelasticity as well as plastic deformation during the plastic rheology of amorphous alloy are determined within the framework of quasi-point defects theory. The current work aims to reveal the structural heterogeneities of amorphous alloys under the action of dynamics with various temporal scales. The physical background of the activation, propagation and coalescence of defects in amorphous alloys under different mechanical stimuli were reviewed.