# Presentation: 410891

## Fundamentals of Multicomponent Diffusion in Multiphase AlloysYongho 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.**

**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.**

**Notes:**
Experimental research in critical systems for high temperature applications (e.g., Ni-Al, Ni-Cr-X, Fe-Ni-Cr-X (X=Al, Si, Pd, Ge), Fe-Ni-Al and commercial superalloys) are being carried out with newly developed laboratory dedicated for studying multicomponent-multiphase diffusion. This new facility consists of electron probe microanalysis, arc-melt drop-chill-cast furnace, hydrogen-flush vacuum system, three-zone tube-furnace, and has prompted collaborative on-going research with INL, ORNL, NIST, GE, and Siemens. Quantitative understanding of diffusional interactions (e.g., thermodynamics and kinetics) in multicomponent systems will provide data and framework for predictive modeling of microstructural development. These research activities for metallic alloys will provide scientific understanding of multicomponent-multiphase alloys that enhance and improve design, processing and application of alloys for high temperature. 

## Fundamentals of Multicomponent Diffusion in Multiphase AlloysYongho Sohn, University of Central Florida, MET DMR-0238356 

**Fundamentals of Multicomponent Diffusion in Multiphase Alloys****Yongho Sohn, University of Central Florida, MET DMR-****0238356**

_**Education and Traineeship**_
**Mr. 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**

**Notes:**
Day-to-day research activities are carried out by graduate and undergraduate research assistants. This NSF program currently supports two Ph.D. students (Mr. N. Garimella and Mr. R. Mohanty) and two undergraduate research assistants (Ms. Ananda Leon and Mr. Nathan Hotaling). Additional contribution to this program is made by Ms. Jing Liu, a fellow of Zonta International Amelia Earhart Fellowship. Previously supported students, Mr. Emmauel Perez (M.S.) has started his doctoral program in materials with project from Idaho National Laboratory, Mr. Travis Patterson (B.S.) has started his doctoral program in materials with project from Siemens, and Ms. Monica Hopkins (B.S.) started her M.S. program in materials with another faculty member in UCF with research emphasis on biomaterials.

This program hosted and sponsored 2006 Central Florida Materials Camp, also sponsored by Siemens Power Generation, ASM International, ASM Central Florida Chapter, and FEI Company. 14 high school students and 4 high school teachers participated in this Saturday-camp with lectures, demonstrations, and hands-on laboratories. Laboratory activities explored the fundamental concepts in crystallography, shape-memory alloys, stress-corrosion, allotropy, twins, fracture. This camp will continue in 2006.

Mr. Munawar Bijani (visually impaired), Ms. D. Bernard and Ms. A. Ewh, attendees of Materials Camp 05 and 06 has entered UCF’s engineering and computer science program as freshmen.

For professional societies such as TMS, ACERS, AVS and ASM, PI has served as member of symposium organizers, technical committees and invited presenter.