Directory Record for:

John R. Hellmann, Jr.

Title(s):

Professor of Ceramic Science and Engineering

Associate Head - Undergraduate Studies

Department:

Materials Science and Engineering

College/Admin. Unit:

College of Earth and Mineral Sciences

Office Address:

124 Steidle Building

University Park, PA 16802

Office Phone:

(814) 865-0163

Office Fax:

(814) 865-0016

E-Mail Address:

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Web Page(s):

http://www.matse.psu.edu

Research Synopsis:

Thermal, elastic, mechanical properties of ceramic, metal, intermetallic, and composite materials for high temperature applications. Processing/structure/properties/performance relationships. Metastable and equilibrium phase relationships. Polymer precursor routes to fabrication of ceramics and composites via direct foaming and infiltration. Slow crack growth and fracture behavior of glasses and ceramics. Thermal fatigue behavior of monolithic and composite materials.

Technologies Impacted by Research:

Solid oxide fuel cells, heat exchangers, radiant tubes, thermal and environmental barrier coatings, gas turbine and aerospace propulsion systems, molten metal and hot gas filtration, gas separation, glass manufacturing, machine tools and tribological applications, preceramic polymer precursor processing of foams, composites, and coatings, ceramic-, glass-, metal- and intermetallic matrix composites, proppants and applications of advanced materials in oil recovery.

Selected Publications:

P. Colombo, J.R. Hellmann, and D.L. Shelleman, "Mechanical Properties of Silicon Oxycarbide Ceramic Foams," J. Am. Ceram. Soc., 84(102245-51(2001)
M. J. Pan, P.A. Hoffman, D.J. Green, and J.R. Hellmann, "Elastic Properties and Microcracking Behavior of Particulate Titanium Diboride-Silicon Carbide Composites," J. Am. Ceram. Soc., 80(3)692-98(1997)
M.H. Krohn, J.R. Hellmann, D.L. Shelleman, C.G. Pantano, and G.S. Sakoske, "Biaxial Flexure Strength and Dynamic Fatigue of Soda-Lime-Silica Float Glass," J. Am. Ceram. Soc., in press