Diffusion-controlled Alloying of Single-phase Multi-principal Covalent Transition Metal Carbides with Enhanced Damage tolerance and Exceptional Thermal Properties

TL;DR

This paper introduces a diffusion-controlled alloying method to synthesize single-phase multi-principal covalent transition metal carbides with enhanced mechanical and thermal properties, overcoming previous synthesis challenges.

Contribution

It presents a novel diffusion-driven synthesis strategy for covalent MPTMCs with a single FCC phase and demonstrates improved toughness, hardness, and thermal insulation.

Findings

Successful synthesis of single-phase MPTMCs at lower temperatures

MPTMCs exhibit high fracture toughness and hardness

Achieved extremely low thermal diffusivity

Abstract

Multicomponent alloying has displayed extraordinary potential for producing exceptional structural and functional materials. However, the synthesis of single-phase, multi-principal covalent compounds remains a challenge. Here we present a diffusion-controlled alloying strategy for the successful realization of covalent multi-principal transition metal carbides (MPTMCs) with a single face-centered cubic (FCC) phase. The increased interfacial diffusion promoted by the addition of a nonstoichiometric compound leads to rapid formation of the new single phase at much lower sintering temperature. Direct atomic-level observations via scanning transmission electron microscopy demonstrate that MPTMCs are composed of a single phase with a random distribution of all cations, which holds the key to the unique combinations of improved fracture toughness, superior Vickers hardness, and extremely lower thermal diffusivity achieved in MPTMCs. The present discovery provides a promising approach toward the design and synthesis of next-generation high-performance materials.