Scientists at the Naval Research
Laboratory (NRL), in collaboration with scientists at the University
of Virginia, have developed an experimental technique that combines
serial sectioning and computer-aided reconstruction for the
three-dimensional
analysis of the internal microscopic structure or
"microstructure"
of materials. Using this method of materials characterization
opens a new avenue for visualizing the true three-dimensional
nature of microstructures, which is critical to the entire materials
field, according to Dr. George Spanos of NRL's Materials Science
and Technology Division (MSTD).
The serial sectioning technique consists of incremental polishing
through a thin layer (0.2 µm) of material, chemically etching
the polished surface, applying reference marks, and performing
optical or scanning electron microscopy on selected areas, Dr.
Spanos explains. After computer-aided registry to properly align
the micrographs from each section, the series of images are viewed
as both video sequences that "step through" the material
slice-by-slice, and as three dimensional reconstructions using
advanced computer visualization techniques.
Scientists in the materials field
have typically used conventional optical and electron microscopy
to characterize microstructures. However, these techniques usually
provide only single two-dimensional views of materials. Researchers
thirty years ago realized that three-dimensional information
would be very helpful in their understanding of materials. However,
at that time, the computer technology to make this type of analysis
worthwhile was not readily available. It is the advances in computer
technology, according to Dr. Spanos, that have enabled scientists
today to develop this enhanced three-dimensional analysis technique.
The team of scientists working on this project, headed by Dr.
Spanos, includes Drs. Milo Kral and Peter Moore both of MSTD
and Mr. Charles Williams of NRL's Visualization Laboratory.
This new three-dimensional reconstruction technique is an important
tool that allows scientists to have a better understanding of
microstructural development, and in turn improves their control
of the mechanical and physical properties of advanced materials
used in the Fleet.
The U.S. Naval Research Laboratory is the Navy's full-spectrum corporate laboratory, conducting a broadly based multidisciplinary program of scientific research and advanced technological development. The Laboratory, with a total complement of nearly 2,500 personnel, is located in southwest Washington, D.C., with other major sites at the Stennis Space Center, Miss., and Monterey, Calif. NRL has served the Navy and the nation for over 85 years and continues to meet the complex technological challenges of today's world. For more information, visit the NRL homepage or join the conversation on Twitter, Facebook, and YouTube.
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