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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 | M A R C H 2 0 1 6
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METALS | POLYMERS | CERAMICS
METAL STRENGTHENED
WITH NANOPARTICLES
A super-strong, lightweight struc-
tural metal was developed by uniformly
dispersing silicon carbide nanoparticles
into a molten magnesium-zinc alloy.
Typically, when used in metal matrices,
ceramic particles tend to clump togeth-
er, reducing strengthening efficiency
and plasticity, and making the metals
hard to machine. To counteract this,
Lianyi Chen, assistant professor of me-
chanical and aerospace engineering at
Missouri University of Science and Tech-
nology, Rolla, and his colleagues devel-
oped a process that produces a uniform
dispersion of 14% nanoparticles in
Mg
2
Zn metal. The team used scanning
and transmission electronmicroscopy to
confirm even dispersion of the nanopar-
ticles. According to Chen, the new metal
has greater strength and plasticity than
conventional metals and could improve
energy efficiency in aerospace, automo-
bile, defense, mobile electronics, and
biomedical applications.
mst.edu.
METAL NANODROPLETS SEEK
AND DESTROY CANCER
Researchers at North Carolina
State University, Raleigh, and the Uni-
versity of North Carolina at Chapel Hill
developed a new drug delivery tech-
nique using biodegradable liquid met-
al nanodroplets to target cancer cells.
According to Zhen Gu, assistant profes-
sor in the joint biomedical engineering
program, “The advance here is that we
SAC can heal itself and regain its original shape after extreme compression.
Courtesy of Jeff Fitlow.
Norsk Titanium,
Norway, and
Premium Aerotec,
Germany, have
taken the initial step in a joint
qualification program for additive-
ly manufactured titanium aircraft
components. The first shipment of
Airbus test parts manufactured by
Norsk’s rapid plasma deposition
process was recently finish ma-
chined by Premium Aerotec. Fol-
lowing an engineering analysis of
the Ti-6Al-4V sample parts, results
will be used for the fast-track qual-
ification program.
norsktitanium. com , premium-aerotec.com.
BRIEFS
Orbital ATK Inc.,
Dulles, Va., was awarded a contract from
United
Launch Alliance
(ULA), Centennial, Colo., for large composite structures
as part of the current United States Air Force Evolved Expendable Launch
Vehicles program. Orbital will produce the hardware for ULA from
2016–2019, supporting Atlas V and Delta IV vehicle launches through
2021. The order will include fairings, payload adapters and diaphragms,
interstages, nose cones, and structures providing main engine thermal/
aerodynamic protection.
orbitalatk.com.
FLEXIBLE COMPOSITE
HEALS ITSELF
Researchers at Rice University,
Houston, developed a material called
SAC (for self-adaptive composite), a
matrix of micron-scale spheres that
possesses self-healing and reversible
self-stiffening properties. The poly-
mer components, polyvinylidene fluo-
ride (PVDF) and polydimethylsiloxane
(PDMS), begin as a powder and a vis-
cous liquid. With the addition of a sol-
vent and controlled heating, the PDMS
stabilizes into solid spheres that provide
the reconfigurable internal structure.
Other self-healing materials en-
capsulate liquid in solid shells that
leak when cracked, but in SAC, the tiny
spheres of PVDF encapsulate much of
the liquid, and the viscous PDMS coats
the entire surface, making the spheres
extremely resilient. Researchers found
a maximum 683% increase in the ma-
terial’s storage modulus. SAC could be
used as a biocompatible material for
tissue engineering or as a lightweight,
defect-tolerant structural component,
say researchers.
rice.edu.
Premium Aerotec Ti-6Al-4V
sample part additively manufactured by
Norsk Titanium. Courtesy of Business Wire.