The high-temperature deformation behavior of Pd20Pt20Cu20Ni20P20 metallic glass

Pd₂₀Pt₂₀Cu₂₀Ni₂₀P₂₀ metallic glass exhibits a prominent β relaxation process, which is conducive to plastic deformation and is an ideal model alloy for studying the correlation between deformation mechanism and microstructure. In this work, the high-temperature rheological and creep behavior of Pd₂₀Pt₂₀Cu₂₀Ni₂₀P₂₀ metallic glass were systematically studied. Within the framework of the free volume model, the high-temperature rheological behavior near the glass transition temperature can be effectively examined through strain-rate jump and uniaxial tensile experiments. The results indicate that the plastic deformation behavior strongly depend on temperature and strain rate. A high value of the activation volume value for plastic deformation can be ascribed to the β relaxation. To further explore the high-temperature deformation behavior, creep experiments were performed near the β relaxation temperature range. Taking microstructural heterogeneity into account, the evolution of strain can be characterized using the empirical Kohlrausch-Williams-Watts equation and the generalized Kelvin model. The results show that annealing below the glass transition temperature leads to the annihilation of defects, an increase in the characteristic relaxation time. This work provides valuable insights into the mechanical behaviors of metallic glass at high temperatures, which is the key to develop the materials with improved mechanical properties for high temperature applications.