Fig. 5: Signatures of strain glass transition in Nb6-HEA.
a, b In-situ step-scanned XRD patterns of Nb6-HEA, taken at 170 K (a) and 298 K (b). c Differential scanning calorimetry (DSC) curve of Nb6-HEA, showing the absence of martensitic transformation peak. d Normalized (at 300 K) electrical resistivity curve of Nb6-HEA for both cooling and heating, and the insets schematically illustrate the evolution of B19’ nano-domains with temperature. e, f Frequency-dependent (different colours represent frequency of 1, 2, 4, 10 and 20 Hz, respectively) storage modulus (e) and internal friction tan δ (f, δ is the phase difference between stress and strain) obtained by dynamical mechanical analysis (DMA) measurements, where the internal friction peaks follow the Vogel-Fulcher relation with an ideal freezing temperature T0 = 194 K (inset of f). g Schematic transition diagram for the B2 austenite in present HEA system, showing that doping of excess Nb can alter the martensitic transformation into strain glass transition, where Ms stands for martensitic transformation start temperature, Tg stands for peak temperature of internal friction, and STG stands for strain glass.
