David E. Luzzi Professor 326A LRSM 215.898.8366 luzzi@lrsm.upenn.edu

Ph.D., Materials Science, Northwestern University, 1986.

B.E., Engineering Physics, Stevens Institute of Technology, 1980.

Research Interests

Structure / Property Relationships at Nanometer Length Scales; Intermetallic Compounds and Composites; Interfaces: Structure, Diffusion, Phase Transformations and Mechanical Properties; Carbon Nanotubes; Electron Microscopy.

Current Research Projects

Interfaces in Structural Materials

The successful development of advanced structural materials requires a basic understanding of interface structure at the atomic level and the resultant implications for interface properties. We are investigating interface diffusion, segregation and strength using polysynthetically-twinned TiAl as a model system. The special interfaces in this technologically important material allow measured properties to be correlated with the atomic structure at the interface. The diffusion of solute along the interfaces is measured by in-situ heating experiments in an Auger electron spectrometer. Segregation of solute to the interfaces is measured by x-ray fluorescence spectrometry and electron energy loss spectroscopy in a field-emission transmission electron microscope. In all cases, the atomic structure at the interfaces is solved using high-resolution electron microscopy and image calculations, together with atomistic simulations of the energetics of candidate structural models.

Mechanical Properties of Laves Phases

The Laves phases comprise the largest structural class of intermetallic compounds. In recent years, there has been an increase in interest in these materials as potential applications are found. At the present time, Laves phase materials are being studied as next generation hydrogen storage materials and as high temperature structural materials for gas turbine engines. Our studies are concentrated on developing an understanding of the mechanical deformation properties of Laves phase materials at room temperature. Our approach incorporates alloy design and production, mechanical testing, thermal analysis, x-ray diffraction and electron microscopy.

Structure and Properties of Carbon Nanotubes

Due to their unique mechanical and electronic properties, it is widely assumed that the carbon nanotube will prove to be an important technological material. Yet, the study of nanotubes is in its infancy and little is known about the synthesis, processing, and properties. We have recently shown that C60 fullerenes are encapsulated within single wall carbon nanotubes. Under an electron beam, the contained molecules are observed to move and coalesce. The nanotube/C60 heterostructure provides a wonderful model system for the study of one-dimensional physics. We are pursuing this through in-situ experiments in the TEM. Other work involves the characterization of electron beam-nanotube interactions and the determination of processing conditions under which the various nanotube-derivative structures are formed or isolated.

Selected Recent Publications

• "Abundance of Encapsulated C60 in Single-Wall Carbon Nanotubes," B. Burteaux, A. Claye, M. Monthioux, B. W. Smith, D. E. Luzzi, and J. E. Fischer, Chem. Phys. Lett., 310 (1999) 21.
• "Carbon Nanotube Encapsulated Fullerenes, a Unique Class of Hybrid Materials," B. W. Smith, M. Monthioux, and D. E. Luzzi, Chem. Phys. Lett., 315 (1999) 31.
• "Formation Mechanism of Fullerene Peapods and Coaxial Tubes: A Path to Large Scale Synthesis," B. W. Smith and D. E. Luzzi, Chem. Phys. Lett., 321 (2000) 169.
• "Room Temperature Deformation Behavior of Hf-V-Ta C15 Laves Phase," W.-Y. Kim, D. E. Luzzi, and D. P. Pope, Acta Mater. (2000), in press.