Unconventional Alloys Confined in Nanoparticles: Building Blocks for New Matter

Abstract

•Unprecedented alloys (e.g., HEAs) are formed via vapor-crystal transformation •Brief oscillatory sparks mix vapors that are quenched to create 55 distinct alloys •Miscibility limits for mixing bulk-immiscible systems are broken at the nanoscale •Mixing abilities diversify materials for additive manufacturing and catalysis Manufacturing unconventional alloys remains challenging owing to the seamless interplay between kinetics and thermodynamics. High-entropy alloys (HEAs), for example, enable paradigm shifts in materials science but these shifts are hindered by traditional liquid-solid transformations. In contrast, vapor–crystal transformations offer the most kinetically efficient pathways to form alloys. Here, a well-mixed vapor is quenched to create 55 distinct alloys confined in nanoparticles (NPs), including unprecedented ones. This confinement is found to stabilize their alloyed states. Unlike precursor feeding, a microseconds-long oscillatory spark mixes the vapors and determines the composition of the alloy NPs. To epitomize practicalities, we apply the NPs as integral building blocks for high-performance catalysts and to nanoscale additive manufacturing. The resulting HEA nanostructures cannot be fabricated by other additive manufacturing techniques. The present work breaks the miscibility limits, thereby providing a powerful roadmap to uncharted territories in metallurgy, catalysis, and additive manufacturing. Manufacturing unconventional alloys remains challenging owing to the seamless interplay between kinetics and thermodynamics. High-entropy alloys (HEAs), for example, enable paradigm shifts in materials science but these shifts are hindered by traditional liquid-solid transformations. In contrast, vapor–crystal transformations offer the most kinetically efficient pathways to form alloys. Here, a well-mixed vapor is quenched to create 55 distinct alloys confined in nanoparticles (NPs), including unprecedented ones. This confinement is found to stabilize their alloyed states. Unlike precursor feeding, a microseconds-long oscillatory spark mixes the vapors and determines the composition of the alloy NPs. To epitomize practicalities, we apply the NPs as integral building blocks for high-performance catalysts and to nanoscale additive manufacturing. The resulting HEA nanostructures cannot be fabricated by other additive manufacturing techniques. The present work breaks the miscibility limits, thereby providing a powerful roadmap to uncharted territories in metallurgy, catalysis, and additive manufacturing.