Senior Engineer Design Engineers

HEEMANN YUN

**** ********** ***., ** *****

Mobile 440-***-****

**********@*****.***

Work Experience:

General Atomics, Electro-magnetic System: Senior Engineer, Fiber-tow Prepreg-based Ceramic Composite Process developments (CMC) for Nuclear Fuel Cladding Application Department

06/2020 to 04/2024, San Diego, CA

Demonstrated a General Atomics (GA) version of the fiber-tow pre-preg-based SiC/SiC and C/C CMC fabrication; from fiber-tow, continuous interfacial SiC fiber tow coatings, to polymer-driven C and SiC matrices. Duties included hands-on pre-preg CMC processing works for nuclear fuel cladding tube applications, and CMC-material discussion with internal CMC design engineers and external customers of DoD and DoE.

1.Initiating and demonstrating GA-version of pre-preg raw materials including polycarbosilane (PCS) polymers and water-based pre-preg ceramic slurries

2.Set-up and fabricating continuous interfacial coatings for the fiber-tow prepreg C and SiC CMC

3.Assisting GA-version SiC fiber research and developments, melt-spinnable PCS, multi-filament spun green fibers, cure / pyrolysis SiC fibers

4.Build-up GA Pre-preg team with five engineers and two technicians

5.Organizing two weekly and one bi-weekly TEAMS meeting to discuss weekly issues and advances

6.Formation of GA pre-preg CMC specifications; fiber-tow pre-preg tapes, sheets, X-ray computer tomography (XCT) The exapart dimensions of green forms and CMCs

7.Part quality controls: Thermos-physical property examinations of thermal conductivities and XCT defects / voids

General Electric Aviation: Senior Engineer (Technologist), Composite Processes (CMC)

Materials & Process Engineering Department

05/2011 to 04/2016, Cincinnati, OH

Demonstrated SiC/SiC CMC fabrication (from A to Z) using two types of starting fibers and two types of final matrix densification routes and successfully delivered flat/complex shape CMC to internal and external customers. Duties included hands-on CMC processing works for the 2400F and 2700F applications, evaluation of Environmental Barrier Coatings, CMC-material discussion with internal CMC design engineers, and presenting summary and conclusions:

1.Demonstrating hybrid matrix-densification routes such as Polymer-Infiltration-Pyrolysis and Melt-Infiltration to external customers

2.Monitoring outside SBIR project on MI-process modeling by providing actual data for model validation

3.Collaborating with outside partners to demonstrate advanced Sylramic-iBN fibers and deliver CMC for the production validation

4.Collaborating with internal EBC groups for assessing hot-erosion/impact, recession, and CMAS-degradation resistance

5.Closely collaborating with CMC designers to demonstrate complex-shape component, included ply-shapes and tool-designs

6.Mentoring young engineers by teaching general SiC/SiC CMC fabrication steps

7.Teaching GE engineers about SiC ceramic-fiber processing at University of Dayton CMC Class as an invited guest lecturer

National Aeronautics Space Administration – Glenn Research Center/Cleveland State University: Senior Research Engineer

01/1987 to 04/2005, Cleveland, OH

Developed and evaluated new SiC ceramic fibers, SiC/SiC-CMCs, and refractory metals for the Civil Space Technology Initiative Program, Enabling Propulsion Materials Program, Ultra Efficient Engine Technology Program, and Next Generation Launch Vehicle Technology Program, and NASA Internal Research & Development Program. Duties included proposal of the project, guiding new developmental strategies, designing and performing experiments, analyzing results, and presenting summary and conclusions in the following areas:

1.2400F & 2800F SiC/SiC CMC and Sylramic ceramic fiber development, various commercial SiC fiber types, architectures, and various matrices consolidation routes, CVI, MI, and PIP and/or combination of those;

2.Polycrystalline oxide-based and Si-based tow fiber for CMC;

3.Evaluation of the physical and thermo-mechanical properties of the fibers and their composites;

4.Creep modeling of high temperature metal matrix composites, W/Nb-1Zr at 1200 - 1300K; designed experiments, fabricated W/Nb-MMC;

5.Characterization of the fibrous substructures in the heavily drawn and dispersoids-strengthened Mo- and W-alloy fibers, either through solid-solutioning with 4Re or through fine ThO2 or HfC-hardening.

Hahn-Meitner-Institut, West Berlin, FRG: Research Scientist

04/1984 to 01/1987, West Berlin, Federal Republic Germany

Studied the correlation between microstructures and creep and/or LCF properties of nuclear fuel ceramics and heat exchanger materials; examined the creep-fatigue interaction with the hold time experiment at 900K and 1100K; developed new heat-resistant metallic and ceramic materials for the use in the high temperature gas turbine applications.

Education:

University of Aachen (RWTH Aachen), Aachen, Germany (FRG)

Ph.D., Materials Science and Engineering, 1984

Dissertation: “Influence of the Test Atmosphere on the Formation of Cracks due to Creep and the Crack Growth in Commercial High Temperature Superalloys.”

Relevant Coursework:

1. Influence of the Test Atmosphere on the Formation of Cracks due to Creep and the Crack Growth in Commercial High Temperature Superalloys

2. Comparison of Creep Fracture in Air and in Simulated High Temperature Reactor Helium

3. Radiation Damages of Metals by the Various Nuclear Reactor Types

4. The Effect of High Temperature Reactor Primary Helium on the Formation and Propagation of Surface Cracks in Incoloy 800H and Inconel 617

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