Temperature-dependent elastic properties of binary and multicomponent high-entropy refractory carbides

Abstract

Available information concerning the elastic moduli of refractory carbides at temperatures (T) of relevance for practical applications is sparse and/or inconsistent. We carry out ab initio molecular dynamics (AIMD) simulations at T = 300, 600, 900, and 1200 K to determine the temperature-dependences of the elastic constants of rocksalt-structure (B1) TiC, ZrC, HfC, VC, and TaC compounds as well as multicomponent high-entropy carbides (Ti,Zr,Hf,Ta,W)C and (V,Nb,Ta,Mo,W)C. The second order elastic constants are calculated by least-square fitting of the analytical expressions of stress vs. strain relationships to simulation results obtained from three tensile and three shear deformation modes. Moreover, we employ sound velocity measurements to evaluate the bulk, shear, elastic moduli and Poisson's ratios of single-phase B1 (Ti,Zr,Hf,Ta,W)C and (V,Nb,Ta,Mo,W)C at ambient conditions. Our experimental results are in excellent agreement with the values obtained by AIMD simulations. In comparison with the predictions of previous ab initio calculations - where the extrapolation of finite-temperature elastic properties accounted for thermal expansion while neglecting intrinsic vibrational effects - AIMD simulations produce a softening of elastic moduli with T in closer agreement with experiments. Results of our simulations show that TaC is the system which exhibits the highest elastic resistances to both tensile and shear deformation up to 1200 K, and identify the high-entropy (V,Nb,Ta,Mo,W)C system as candidate for applications that require good ductility and toughness at room as well as elevated temperatures.

References in corpus (12)

• Necessary and Sufficient Elastic Stability Conditions in Various Crystal Systems
• High-entropy high-hardness metal carbides discovered by entropy descriptors
• A Map of the Inorganic Ternary Metal Nitrides
• Simple and accurate model of fracture toughness of solids
• Trends in the elastic response of binary early transition metal nitrides
• Enhancing plasticity in high-entropy refractory ceramics via tailoring valence electron concentration
• Ductile and brittle crack-tip response in equimolar refractory high-entropy alloys
• Adaptive hard and tough mechanical response in single-crystal B1 VNx ceramics via control of anion vacancies
• Uncertainty Quantification and Composition Optimization for Alloy Additive Manufacturing Through a CALPHAD-based ICME Framework
• Strength, transformation toughening and fracture dynamics of rocksalt-structure Ti1-xAlxN (0 <= x <= 0.75) alloys
• Temperature-dependent mechanical properties of ZrC and HfC from first principles
• Finite temperature elastic constants of paramagnetic materials within the disordered local moment picture from ab initio molecular dynamics calculations

Cited by in corpus (3)

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