Relationship between Chemical Composition and Ms Temperature in High-Entropy Shape Memory Alloys

Abstract

Five high entropy alloys with shape memory effect or superelastic effect were prepared by cold crucible melting to understand the effect of their chemical composition on the transformation temperatures. The microstructure and phases of the alloys at room temperature were investigated by optical and scanning electron microscopy. The calorimetric study of these alloys is employed to analyze the reversible transformation from austenite to martensite and to determine the transformation temperatures of the five alloys. The paper presents the results of several published works relating the transformation temperatures of high entropy shape memory alloys (HE-SMA). An experimental database has been built up to understand the influence of the different alloying elements and their related concentrations on the transformation temperature M s (Martensite Start) of the HE-SMAs. An equation is identified using the database to predict the transformation temperature M s of a high entropy shape memory alloy as a function of its weighted chemical composition, which exhibits a metallurgical solutioned treatment (ST) state and a specific mixing entropy (DSmix/ R) range.

Medical high-entropy alloy: Outstanding mechanical properties and superb biological compatibility

“…Frontiers in Bioengineering and Biotechnology frontiersin.org Some bio-HEAs have also been shown to have superelastic properties. Peltier (Peltier et al, 2021) pointed out that for (TiHfZr) 74 (NbTa) 26 , its superelasticity originates from the transition of β↔α" when deformation occurs. The superelastic temperature range is 40-200 °C, which is compatible with the human service environment temperature.…”