Formation and stability of C14 type Laves phase in multi component high-entropy alloys

Abstract

The present investigation reports the formation and stability of multi-component AB2-type Laves phase in Ti–Zr–Ni (V, Cr, Fe, Mn, Co)ternary to octonary alloys system. To probe the formation and stability of AB2-type Laves phase in high-entropy alloys, a series of multi-component alloys have been synthesized via melting under protective Ar atmosphere and subsequent annealing at 525 K for 40 h. Systematic investigation has been carried out to understand phase stability using both thermodynamic and parametric approaches. X-ray diffraction measurement and Rietveld analysis indicate the formation of C14 Laves phase in multi-component alloys. The enthalpy of mixing (ΔHmix), size difference (δ) and valence electron concentrations (VEC) have been found to play stellar role in controlling the formation of multi-component Laves phase in these alloys. The valence electron concentrations and electrons per atom ratio (e/a) dictate the choice of elements for the stabilization of Laves phase in these high-entropy alloys. © 2020