Fundamentals of Multicomponent Diffusion in Multiphase AlloysYongho Sohn, University of Central Florida, MET DMR-0238356 Motivation: Diffusion plays an important role in development and applications of materials that underpin many products and processes. This program aims to advance in phenomenological descriptions and experimental techniques for understanding multicomponent-multiphase diffusion through an integration of fundamental laboratory research and several education/outreach programs.

Facility Development:• Experimental Facility Dedicated for Solid-Solid Diffusion

Couple Studies: Arc Melt, Quartz Capsule, Hydrogen Flush System, Furnaces and Electron Probe Microanalysis.

Experimental Research:• Microstructural Analysis and Quantitative Assessment of

Interdiffusion Between NiAl and Various Superalloys (in Collaboration with Siemens, GE and Exxon-Mobil).• Study of Ternary Diffusion and Phase Equilibria in U-Mo-

Al-X Alloys (X = Si, Zr, Ti, Nb) for Nuclear Fuel Applications (Contract from Idaho National Laboratory and Synergistic Research Activities).• Microstructural Evolution (i.e., Multiphase Diffusion

Couples) in Fe-Ni-Al and Ni-Cr-Al Alloys (in Collaboration with Oak Ridge National Laboratory• Ternary Diffusion and Oxidation in Ni-Cr-X and Fe-Ni-Cr-X

(X=Al, Si, Ge, Pd) Alloy (in Collaboration with ORNL).

Modeling & Phenomenology• Phase-Field Simulation of Multiphase Ternary Diffusion

Couple with Composition-Dependent Thermodynamics and Mobilities.• Developed Framework for Generalized Description of

Interdiffusion Fluxes under Multiple Gradients.

30mNiAl vs. IN738

NiAl

IN73830mNiAl vs. IN738

NiAl

IN738

p

Dij

n (1

0-15

m2 /

sec) D

311

~

D312

~

D321

~D

322

~

Dij

n (

10-1

5 m

2 /se

c)

p

5-Side D311

~

D312

~

D321

~

D322

~

9-Side

1(Ni)

2(Al)

5

(B2)9

(B2)

3(Fe)

Co

nce

ntr

atio

n (

ato

m f

ract

ion

)

Distance (m)

10 m

Investigating Interdiffusion Microstructure and Analyzing Concentration Profiles for Alloys Critical in Energy Production.

Determination of Composition-Dependent Interdiffusion Coefficient based on Multiples Moments (p) of Interdiffusion Fluxes.

Fundamentals of Multicomponent Diffusion in Multiphase AlloysYongho Sohn, University of Central Florida, MET DMR-0238356

Education and TraineeshipMr. E. Perez who Earned M.S. with NSF Support is now a

Ph.D. Student working on a Project from Idaho National Laboratory, Interdiffusion in U-Mo-Al Alloys.

Mr. N. Garimella who is Working on Interdiffusion in Ni-Cr-X and Fe-Ni-Cr-X (X = Al, Si, Ge, Pd) with NSF Support is Now a Ph.D. Candidate.

Mr. R. Mohanty who is Working on Multiphase Interdiffusion with NSF Support has Passed His Qualifying Examination.

Mr. T. Patterson (B.S.) who Assisted This NSF Program Has Entered Ph.D. Program in Materials at UCF.

Ms. M. Hopkins (B.S.) who Assisted This NSF Program Has Entered M.S. Program in Materials at UCF.

Ms. A. Leon (Junior) and Mr. Nathan Hotaling (Senior) will Continue to Contribute to This Program as Undergraduate Research Assistants. Broader Impact / Outreach

Hosted 2006 Materials Day-Camp for Local High School Students (14) and Teachers (4) with Additional Sponsorships From ASM Central Florida Chapter, Siemens Power Generation, FEI Company.

Mr. Munawar Bijani (Visually-Impaired) Student, who Worked on this Program is now a Freshman of Computer Science.

Attendees of Materials Camp 05 and 06, Ms. A Ewh, Mr. M. Bijani, Ms. D. Bernard, Entered Engineering and Computer Science Program at UCF for B.S.

PI Organized 2 International Symposiums (TMS and ACERS), Gave 4 Invited Talks at International Symposiums (AVS, ASM, MS&T, DSL06), and was an Invited Scientist at NIMS in Japan.

Sohn Group, Spring 2006