CREEP MECHANISM OF Pd₂₀Pt₂₀Cu₂₀Ni₂₀P₂₀ HIGH ENTROPY AMORPHOUS ALLOY

In the current work, a Pd₂₀Pt₂₀Cu₂₀Ni₂₀P₂₀ high-entropy metallic glass was selected as the model system to explore the deformation mechanisms under different loading conditions. Creep cyclic loading and cyclic loading-unloading experiments were carried out to elucidate the deformation mechanisms, steady-state creep rate, creep stress index, and the evolution of relaxation time spectra. This study systematically investigated the effects of temperature, cyclic loading, and recovery time on the creep behavior of this high-entropy metallic glass, offering a comprehensive analysis of its response to various stress and thermal conditions. Our findings revealed that the creep behavior of the alloy significantly depended on both temperature and stress, exhibiting superior creep resistance under low temperature and stress conditions. In these environments, the deformation was primarily dominated by elastic deformation. However, with the increase of temperature, the resistance to creep progressively weakened, and viscoelastic (viscoplastic) deformation became the dominant deformation mechanism. Notably, the impact of cyclic stress on creep deformation was found to be negligible at low temperatures but became markedly significant at higher temperatures. This suggests that cyclic loading exacerbated creep behavior, leading to a notable increase in the steady-state creep rate as temperature rises. Recovery duration markedly affected the instantaneous elastic deformation and viscoelastic deformation, albeit with a limited modulatory capacity on viscoelastic deformation. After unloading, the deformation capacity of model alloy gradually increases, alleviating creep inhibition. Furthermore, the wide distribution of relaxation times and their sensitive response to cyclic stress highlighted the complexity of the creep mechanism and the evolution of structures across multiple time scales. This study, through systematic experiments and analysis, deepened the understanding of the creep behavior and control mechanisms of high-entropy metallic glasses. It provides important theoretical foundations and practical guidance for the design and application of high-performance high-entropy metallic glasses and holds significance for the future development of advanced materials with enhanced creep resistance.