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Corresponding Icosahedral Order

Structural and Microstructural Studies of Ti/Zr and Al-Based Quasicrystals, Approximants, and Metallic Glasses Kenneth F. Kelton, Washington University, St. Louis, MET DMR – 0307410. Slope is steady state nucleation rate, I s. Zr 59 Ti 3 Cu 20 Ni 8 Al 10. Number of Grains (m -3 ).

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Corresponding Icosahedral Order

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  1. Structural and Microstructural Studies of Ti/Zr and Al-Based Quasicrystals, Approximants, and Metallic Glasses Kenneth F. Kelton, Washington University, St. Louis, MET DMR – 0307410 Slope is steady state nucleation rate, Is Zr59Ti3Cu20Ni8Al10 Number of Grains (m-3) Nucleation Temperatures Intercept is induction time,θ • First quantitative time-dependent • nucleation data in a metallic glass • Extremely small nucleation barrier ( ) Time (min) Quasicrystal Nucleation Corresponding Icosahedral Order • Wide angle synchrotron XRD data • Reverse Monte Carlo fits show strong local • icosahedral short range order in glass • (Honeycutt Andersen analysis – below) • Comparison with liquid data of same alloy • demonstrates growth of icosahedral order • on glass formation (nature of glass transition) Most Quantitative Proof of Frank’s Hypothesis for Glass Crystallization

  2. Structural and Microstructural Studies of Ti/Zr and Al-Based Quasicrystals, Approximants, and Metallic Glasses Kenneth F. Kelton, Washington University, St. Louis, MET DMR – 0307410 Education: Undergraduate students Drew Newman and Zach Marine and graduate students Youtao Shen, Debujit Saha, Victor Wessels Lydia Spoor and Nicholas Mauro were supported by this grant. Student Presentations: Graduate student presentations at the American Physical Society Meeting, March, 2006 – Youtao Shen “Transient nucleation in a Zr-Ti-Cu-Ni-Al metallic glass”; Tae Ho Kim “The role of Ti in the formation of Zr-Ti-Cu-Ni-Al glasses.” Outreach: Kelton is the President of UCSAC, a science advisory council dedicated to improving science education in University City, MO, a majority African-American school system adjacent to Washington University. Right picture: Dr. Tyrone Daulton (center, standing), the Electron Microscopist in the Center of Materials Innovation at Washington University, shows graduate student Lydia Spoor some of the finer points for energy filtered TEM studies using the JEOL 2100 located at Washington University. Graduate students Victor Wessel (front) and Karyn Spence and Professor Kelton look on.

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