Evaluating Binary Molybdenum Alloys as Strong and Ductile High-Temperature Materials

Area of Science:

• Materials Science
• Metallurgy
• Computational Materials Science

Background:

• Molybdenum (Mo) alloys offer superior high-temperature strength compared to nickel-based superalloys but often lack sufficient ductility.
• The commercial availability and application scope of Mo alloys are significantly limited compared to Ni-based superalloys.
• Investigating less-explored binary Mo-X systems presents an opportunity for discovering novel refractory alloys.

Purpose of the Study:

• To systematically investigate binary Mo-X systems for potential refractory alloy applications.
• To identify Mo-X systems suitable for either solid-solution or precipitation strengthening.
• To guide the development of Mo alloys with improved mechanical properties, particularly ductility, for high-temperature use.

Main Methods:

• Utilized computational thermodynamics (CALPHAD) and first-principles calculations to analyze thermodynamic features.
• Employed mechanistic modeling to assess mechanical properties, including yield strength, ductility, and creep resistance.
• Conducted a down-selection process from 92 Mo-X systems to identify promising candidates.

Main Results:

• Identified three candidate systems for precipitation strengthening: Mo-B, Mo-C, and Mo-Si.
• Identified one candidate system for solid-solution strengthening: Mo-Re.
• Highlighted the unique role of Rhenium (Re) in enhancing the ductility of Mo alloys.

Conclusions:

• The study successfully identified promising binary Mo-X systems for developing advanced refractory alloys.
• The computational workflow provides a robust framework for discovering and optimizing refractory alloys.
• Further research can focus on composition optimization, particularly incorporating Re, to match Ni-based superalloy performance.