Todd C. Hufnagel


		Faculty

Todd C. Hufnagel
Associate Professor of Materials Science and Engineering

Ph.D. Materials Science and Engineering
Stanford University, 1995

M.S. Materials Science and Engineering
Stanford University, 1991

B.S. Metallurgical Engineering
Michigan Technological University, 1989

Mailing address
102 Maryland Hall
3400 North Charles Street
Baltimore, MD 21218-2681



Phone: 410-516-6277	Fax: 410-516-5293	E-mail:

My research interests encompass phase transformations, mechanical properties and structure-property relationships, with a particular emphasis on amorphous metallic alloys (also called "metallic glasses"). Amorphous alloys have advantageous mechanical and magnetic properties due to their lack of long-range crystalline order. However, characterizing the structure of an amorphous material is a significant challenge, so a theme of our research is the application of advanced structural characterization tools to the study of metallic glasses.

For instance, we study phase separation and crystallization in bulk metallic glasses using small-angle X-ray scattering (SAXS), anomalous small-angle X-ray scattering (ASAXS), and in situ X-ray diffraction in real time. The results of these studies are applied to the design of new alloys and processes for producing metallic glasses in bulk form. We also use resonant anomalous x-ray scattering and extended X-ray absorption fine structure (EXAFS) to study the atomic-scale structure of amorphous metallic alloys.

The lack of long-range atomic order in bulk metallic glasses gives them unique mechanical properties, including high strength and very large elastic elongations. Part of our research explores these properties, including the formation of highly localized regions of deformation called shear bands. Shear band formation and motion have a significant effect on the deformation of metallic glasses, particularly at high strain rates. We use advanced transmission electron microscopy (TEM) techniques to study shear bands, including high resolution TEM (HRTEM) and fluctuation microscopy.

The results of these fundamental investigations are also applied to the design of new materials with improved properties. For instance, we have developed a novel technique for producing composite materials consisting of micron-scale crystalline particles embedded in a metallic glass matrix. These composites can withstand much larger strains before failure than the unreinforced metallic glasses.

[ Research Group] [ Research Projects] [ Laboratory Facilities] [ Teaching]

Selected Publications

T. C. Hufnagel. "Finding order in disorder." Nature Mat. 3, 666 (2004).

T. Jiao, L. J. Kecskes, T. C. Hufnagel, and K. T. Ramesh. "Deformation and failure of Zr₅₇Nb₅Al₁₀)Cu_15.4Ni_12.6/W particle composites under quasi-static and dynamic compression." Met. Mat. Trans. A (in press).

A. J. Swiston, Jr., T. C. Hufnagel, and T. P. Weihs. "Joining bulk metallic glass using reactive multilayer foils." Scripta Mater. 48, 1575 (2003).

W. J. Wright, T. C. Hufnagel, and W. D. Nix. "Free volume coalescence and void formation in shear bands in a metallic glass." J. App. Phys. 93, 1432 (2003).

T. C. Hufnagel and S. Brennan. "Short- and medium- range order in (Zr₇₀Cu₂₀Ni₁₀)_90-xTa_xAl₁₀ bulk amorphous alloys." Phys. Rev. B 67, 014203 (2003).

M. W. Chen, M. L. Glynn, R. T. Ott, T. C. Hufnagel, and K. J. Hemker. "Characterization and modeling of a martensitic transformation in platinum modified diffusion aluminide bond coats for thermal barrier coatings."Acta Mater. 51, 4279 (2003).

Slip steps on the surface of a Zr-based metallic glass.
T. C. Hufnagel, P. El-Deiry, and R. P. Vinci, Scripta Mater. 43, 1071 (2000).

J. Li, X. Gu, and T. C. Hufnagel. "Using fluctuation microscopy to characterize structural order in metallic glasses." Micros. Microanal. 9, 509 (2003) (preprint).

C. Fan, R. T. Ott, and T. C. Hufnagel. "Metallic glass matrix composite with precipitated ductile reinforcement." Appl. Phys. Lett. 81, 1020 (2002).

J. Li, F. Spaepen, and T. C. Hufnagel. "Nanometre-scale defects in shear bands in a metallic glass." Phil. Mag. A 82, 2623 (2002).

J. Li, Z. L. Wang, and T. C. Hufnagel. "Characterization of nanometer-scale defects in metallic glasses by quantitative high resolution transmission electron microscopy." Phys. Rev. B. 65, 144201 (2002).

T. C. Hufnagel, T. Jiao, Y. Li, L.-Q. Xing, and K. T. Ramesh. "Deformation and failure of Zr₅₇Ti₅Cu₂₀Ni₈Al₁₀ bulk metallic glass under quasi-static and dynamic compression." J. Mater. Res. 17, 1441 (2002).

L.-Q. Xing, Y. Li, K. T. Ramesh, J. Li, and T. C. Hufnagel. "Enhanced plastic strain in Zr-based bulk amorphous alloys." Phys. Rev. B 64, 180201(R) (2001).

L.-Q. Xing, T. C. Hufnagel, J. Eckert, W. Loser, and L. Schultz. "Relation between short-range order and crystallization behavior in Zr-based amorphous alloys." Appl. Phys. Lett. 77, 1970 (2000).