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Intermetallic compounds (metallic
materials composed of definite proportions
of two or more elemental metals) resist
oxidation and remain strong at high
temperatures, making them useful for
energy technologies. But until recently,
these compounds were too brittle to
be fabricated into conventional shapes
using traditional methods. In 1981,
Oak Ridge National Laboratory started
a program to increase understanding
of intermetallic compounds and develop
scientific principles for improving
their properties. Following a Japanese
report suggesting that small amounts
of boron made a nickel aluminide compound
more ductile, Oak Ridge researchers
led by Chain T. Liu determined the
mechanism behind the change. They
also showed that iron aluminides are
intrinsically ductile at ambient temperatures
and that brittleness is caused by
moisture in the air. Quantum mechanical
calculations demonstrated a mechanism
that reduced the cohesive strength
of atomic layers in these alloys by
70 percent, a discovery that led to
new and improved alloy designs. Liu
was awarded the 2001 Acta Metallurgica
Gold Metal for his outstanding leadership
and achievements in this research.
The Office of Science then worked
with DOE offices of Energy Efficiency
and Fossil Energy to fund a research
program on intermetallic compounds,
an effort that has won three R&D 100
awards from R&D Magazine
recognizing significant new technologies,
and has resulted in more than 16 patents
and 12 licenses.
Scientific Impact:
Materials and processing research
at Oak Ridge has increased scientific
understanding of intermetallic compounds.
This work overcame the brittleness
problem and improved manufacturability,
thus making it practical to use nickel
and iron aluminides for high temperature
engineering applications.
Social Impact: This
research has helped to improve product
quality and reduce costs. For instance,
the use of nickel-aluminide dies for
the hot forging process improves the
quality of steel parts in automobiles,
and iron-aluminide filters used to
remove ash particles during coal gasification
reduce costs and resist the corrosiveness
of hydrogen sulfide in the gas stream.
Reference: Pope,
D. P., C, T. Liu, S. H. Whang, and
M. Yamaguchi, eds., High Temperature
Intermetallics, Elsevier, New
York (1997).
URL: http://www.ornl.gov/bes/BES/abad/alloying.htm
http://www.ornl.gov/bes/BES/abad/staff6/liu.htm
Technical Contact:
Don Freeburn, Office of Basic Energy
Sciences, 301-903-3156
Press Contact: Jeff
Sherwood, DOE Office of Public Affairs,
202-586-5806
SC-Funding Office:
Office of Basic Energy Sciences |