

Episode 91: High Entropy Alloys
59 snips Jul 24, 2024
Discover the revolutionary world of high entropy alloys (HEAs), materials that defy traditional metallurgy rules with their unique compositions. These alloys boast exceptional strength, hardness, and thermal stability, transforming the materials industry. Experts discuss the simultaneous discovery of HEAs at top universities and their implications for future technological advancements. Explore the cutting-edge techniques for manufacturing these alloys and their immense potential in various applications, from aerospace to energy solutions.
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Cantor's Surprising HEA Discovery
- Brian Cantor and colleagues discovered high entropy alloys (HEAs) with equi-atomic ratios forming a surprising single FCC phase.
- They tried up to 20 element alloys, finding single-phase behavior only when down to five elements including iron, manganese, chromium, cobalt, and nickel.
HEAs Defy Gibbs Phase Rule
- Gibbs phase rule suggests multiple phases when alloying five components equally, yet HEAs defy this by forming single-phase structures.
- This defies expectations because normally multiple phases would form with increasing components.
Entropy Stabilizes HEA Phases
- HEAs derive their name from high configurational entropy due to multiple principal elements in equal ratios.
- This increased entropy potentially stabilizes solid solution phases by offsetting enthalpic preferences for multiple phases.