Observing strain glass transition in Ti_(33)Nb_(15)Zr_(25)Hf_(25)O_(2)high entropy alloy with Elinvar effect

Exploring the phase transition of high entropy alloys(HEAs)with multiple major elements is of great importance for understanding the underlying physical mechanisms.Macroscopic martensitic phase tran-sition has been frequently reported in HEAs,however,nanoscale microstructural phase evolution has not been investigated to the same extent.Herein,we have prepared the Ti_(33)Nb_(15)Zr_(25)Hf_(25)O_(2)HEA and investi-gated the strain glass transition and its associated properties using dynamic mechanical analysis and mi-crostructure characterization.We have found that the elastic modulus in Ti_(33)Nb_(15)Zr_(25)Hf_(25)O_(2)HEA deviates from Wachtman’s equation and observed the Elinvar effect in the form of temperature-independent mod-ulus in the temperature range from 150 K to 450 K and frequency-dependence modulus around 220 K.The strain glass transition has been evidenced in Ti_(33)Nb_(15)Zr_(25)Hf_(25)O_(2)HEA by the formation and growth of nano-sized domains during in-situ transmission electron microscopy(TEM)cooling,and substantiated by the broken ergodicity during zero-field-cooling/field-cooling.The strain glass transition is believed to account for the Elinvar effect,where the modulus hardening of nano-sized domains compensates dynam-ically with the modulus softening of the transformable matrix.

Entropic pressure between fluctuating membranes in multilayer systems

Gaining insights into the fluctuation-induced entropic pressure between membranes that mediates cell adhesion and signal transduction is of great significance for understanding numerous physiological processes driven by intercellular communication.Although much effort has been directed toward investigating this entropic pressure,there still exists tremendous controversy regarding its quantitative nature,which is of primary interest in biophysics,since Freund challenged the Helfrich’s well-accepted results on the distance dependence.In this paper,we have investigated the entropic pressure between fluctuating membranes in multilayer systems under pressure and tension through theoretical analysis and Monte Carlo simulations.We find that the scaling relations associated with entropic pressure depend strongly on the magnitude of the external pressures in both bending rigidityand surface tension-dominated regimes.In particular,both theoretical and computational results consistently demonstrate that,in agreement with Helfrich,the entropic pressure p decays with inter-membrane separations c as p^c^(–3)for the tensionless multilayer systems confined by small external pressures.However,our results suggest that the entropic pressure law follows to be p^c^(–1)and p^c^(–3),respectively,in the limit of large and small thermal wavelengths for bending fluctuations of the membranes in a tensionindependent manner for the case of large external pressures.