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arXiv · 2609.06848

A Novel Nb-Based Eutectic Superalloy with Exceptional Ultrahigh-Temperature Mechanical Properties

Ayeman M. Nahin·Alfredo Navarrete·Xiaokun Yang·Eric A. Lass·Mingwei Zhang
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Abstract

Refractory alloys operating above 1300 {\deg}C, beyond the limit of Ni-based superalloys, must balance high-temperature strength, thermal stability, low density, low cost, and room-temperature tensile ductility, a combination that existing refractory alloys have yet to achieve. Here we report a castable Nb-based eutectic superalloy, Nb-10Mo-9.5C (at. %, NMC-1), comprising a uniform lamellar structure of Nb-Mo solid solution and Nb2C carbide phases. NMC-1 achieves 0.2% yield strengths of ~300 MPa and ~200 MPa at 1300 {\deg}C and 1500 {\deg}C, respectively, among the highest reported for Nb-based alloys, with pronounced strain hardening, non-zero room-temperature tensile ductility, and no observed microstructural coarsening after 100 h at 1400 {\deg}C. Its low density (8.65 g/cc) and cost (~$85/kg) yield a specific-strength-per-cost merit index that far surpasses commercial Nb, Mo, Ta, and W alloys, establishing a new design paradigm for ultrahigh-temperature structural materials.

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Ayeman M. Nahin, Alfredo Navarrete, Xiaokun Yang, Eric A. Lass, Mingwei Zhang. 2026-09-06. A Novel Nb-Based Eutectic Superalloy with Exceptional Ultrahigh-Temperature Mechanical Properties. https://arxiv.org/abs/2609.06848

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