A Low-Cost, Strong, and Ductile Single-Phase Nb-Based Refractory Complex Concentrated Alloy

TL;DR

This paper introduces a cost-effective, high-performance Nb-based refractory alloy with superior specific strength and ductility at high temperatures, offering a promising alternative for demanding structural applications.

Contribution

The study designs a novel non-equiatomic Nb-based RCCA with enhanced mechanical properties and reduced cost, outperforming traditional alloys like C-103 at elevated temperatures.

Findings

Surpasses wrought C-103 in specific strength up to 1300°C

Maintains >10% tensile ductility at room temperature

Offers lower raw material cost (~$130/kg) compared to traditional alloys

Abstract

The development of structural materials capable of sustained operation above 1200 {\deg}C is critical for next-generation energy and aerospace systems; however, Ni-based superalloys are fundamentally constrained by their melting temperatures, while conventional Nb-based refractory alloys are limited by modest specific strength and high cost. Here, we report on the design and mechanical performance of a cost-effective, non-equiatomic refractory complex concentrated alloy (RCCA), Nb45Ta15Ti20V20, engineered to overcome these limitations. Specifically, its specific strength surpasses wrought C-103 and rivals additively manufactured (AM) C-103 at temperatures up to 1300 {\deg}C while maintaining extensive room temperature tensile ductility (>10 %). Coupled with a high melting point (~2167 {\deg}C), reduced density (8.67 g/cc), and a raw material cost of ~$130/kg compared to >$500/kg for wrought C-103 and >$2,500/kg for AM C-103, this alloy delivers superior specific strength-cost efficiency, highlighting the promise of non-equiatomic RCCAs as viable alternatives to commercial refractory alloys.