Sept_AMP_Digital

11 / 70

A D V A N C E D
M A T E R I A L S
&
P R O C E S S E S |
S E P T E M B E R
2 0 1 6
1 1
realistic damage. While there were
some discrepancies between the size
and shape of cracks on the resulting EIT
maps and data from visual inspection
and thermograms, overall the approach
detected damage well before it was
visible with infrared thermography.
udel.edu.
Thomas Schumacher (left) and Erik
Thostenson are leading research on a
new technique to monitor the health of
structures such as roads and bridges.
side. Using software, grain boundaries
were connected from one side to the
other, reconstructing their 3D orienta-
tion. This data was combined with elec-
tron microscope images to show the
orientation of individual crystal lattices
within each grain and how they relate
to those of adjacent grains. The new,
nondestructive method determines all
five necessary characteristics of grain
boundaries, whereas previous methods
achieved only two or three. mit.edu.
A NEW LOOK AT
POLYCRYSTALLINE METALS
By combining established testing
technologies in a novel way, research-
ers from Massachusetts Institute of
Technology, Cambridge, and colleagues
devised a new approach to characterize
the microstructure of polycrystalline
metals. The method marries optical
and electron microscopy. It is also fast,
affordable, accurate, and accessible—a
combination not yet achieved with
current testing methods for these met-
als, which are comprised of a random
matrix of multiple small crystals rather
than a single, large crystal, making
them difficult to analyze.
Quantifying the characteristics
of interfaces between crystals in poly-
crystalline metals allows their material
properties to be determined. To do this,
researchers took optical microscope
images of both sides of a sheet of poly-
crystalline metal foil thin enough for
single grains to be seen from either
A newmethod combines optical micros-
copy (left, pink) with electron backscatter
diffraction (right, green) to measure char-
acteristics of the boundaries between
crystal grains. Courtesy of Matteo Seita.