Fig. 2: Multiple macroscopic properties of Nb6-HEA.

a Tensile loading-unloading stress-strain curves of Nb6-HEA tested from 373 K down to 123 K, and inset shows that Nb6-HEA exhibits a nearly temperature-independent (Elinvar-type) modulus over the temperature range of 173–323 K (as indicated by the yellow shading), a behavior contrasting with the elastic modulus hardening of non-transforming spring steel and the elastic modulus softening of Ti-Ni martensitic alloy. b Compressive loading-unloading stress-strain curves of Nb6-HEA with applied stress of 600 MPa, showing thermally-stable non-hysteretic stress-strain response and elastic energy E_elastic (shaded areas), contrasting with a Nb-free (TiZrHf)₅₀Ni₂₅Co₂₀Cu₅ HEA with strongly temperature-dependent elasticity (inset). c A comparison of micro-hardness between Nb6-HEA and conventional structural and elastic materials^41,42,43,44. d Potential polarization curves of Nb6-HEA and Ti-50Ni alloy in NaCl (3.5 wt.%) solution and H₂SO₄ (PH = 3) solution, where E_corr is the corrosion potential, i_corr is the corrosion current density, and the reference electrode is Calomel electrode (SCE).