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Super-strong steel suits military applications and more
Harry Bhadeshia of the Uni-
versity of Cambridge, UK, Depart-
ment of Materials Science and
Metallurgy, has spent the past
three decades researching the na-
ture of steel to develop new alloys
for a range of applications. One of
these alloys, super bainite, has
been licensed to Tata Steel, Mum-
bai, India, and is currently being
manufactured in the UK for use as
super-strong armor for military vehicles and other applications.
Using precise modeling, it was found that there is no lower limit to the temperature at
which bainite can be produced. By heat treating it at temperatures around 200°C for 10 or
more days, a new form results—super bainite. In addition, by adding elements such as sil-
icon and molybdenum, carbides and harmful impurity phases are prevented from forming
in the steel, reducing the likelihood of cracks. Super bainite features a tensile strength of
2.5 GPa, and just 1 m2 can support a weight equivalent to that of 2.5 billion apples. It has
a higher density of interfaces than any other metal, and is the world’s first bulk nanostruc-
tured metal. The strength of super bainite derives not only from its lack of carbides, but also
from the its tiny iron crystals. These crystals are between 20 and 40 nm thick, comparable
to the width of carbon nanotubes. In comparison, the crystals in conventional bainite are
between 200 and 500 nm thick. For more information: Harry Bhadeshia, ,
.
Protecting helicopters and boats with newmaterials
Emerging global trends impact the environment of light tactical interdiction vehicles
for military, law enforcement, and homeland security operations, particularly helicopters
and patrol boats. As these vehicles engage in higher-risk scenarios, they require enhanced
armor protection that will not compromise their speed, agility, range, and payload capac-
ity. Simply adding armor made from traditional materials such as ceramics, glass, aramid,
and even polyethylene is no longer enough. Innovative lightweight materials that can de-
liver reliable protection and optimize vehicle performance, fuel efficiency, capacity, and
maneuverability are necessary. DSM Dyneema, Stanley, N.C., announces Dyneema Force
Multiplier Technology, which reportedly combines breakthroughs in polymer science,
next-generation UHMWPE fiber technology, and unique unidirectional engineering. The
new material reduces the weight of hard ballistics armor by up to 25%, offering greater ve-
hicle agility, speed, fuel efficiency, and capacity. .
Shape memory alloys for buildings
Researchers at the Swiss Federal Laboratories for Materials Science and Technology
(Empa) demonstrate that shape memory alloys (SMAs) can be used in the building indus-
try. SMAs have the ability to return to their original shape after being severely deformed,
either spontaneously or following the application of heat,
making them useful not just for making eyeglass frames, but
also for technical applications such as thermostats, stents, and
micro-actuators. Other applications in the construction in-
dustry are possible as well, such as bridge reinforcement.
The nickel titanium alloys used to make eyeglass frames
and stents are not suitable for use in the construction in-
dustry. Iron-based SMA products are much more attrac-
tive, because both the raw materials and processing costs
are far less expensive.
news
industry
briefs
SAE International, Warrendale,
Pa., is teaming with the University
of Michigan, Ann Arbor, to
combine classroom and laboratory
learning in the Automotive
Composites Technology
Engineering Academy. The five-
day course will be held November
10-14 at SAE International’s Troy,
Mich., office and will provide an
overview of composite materials in
terms of material types such as
carbon, glass, and natural fibers.
The focus, however, will be on
carbon fiber processes, typical
applications, benefits, and
shortcomings. Participants will
learn about terminology, quality
issues, costs and automotive
market needs, and will gain a
holistic understanding of
automotive carbon fiber
and its applications.
Engineers at Massachusetts
Institute of Technology,
Cambridge, Mass., and Lawrence
Livermore National Laboratory
(LLNL), Calif., devised a way to
translate the Eiffel tower to the
microscale—designing a system
that could be fabricated from a
variety of materials, such as
metals or polymers, and that may
set new records for stiffness for a
given weight. The design is based
on the use of microlattices with
nanoscale features, combining
great stiffness and strength with
ultralow density, say researchers.
The actual production of such
materials is made possible by a
high-precision 3D printing process
called projection microstereo-
lithography, as a result of the joint
research. ,
Microscope image of a
single unit of the structure
developed by the team,
called a stretch-dominated
octet truss unit cell, made
from a polymer using 3D
microstereolithography.
METALS POLYMERS CERAMICS
ADVANCED MATERIALS & PROCESSES • SEPTEMBER 2014 8
Perforations in super bainite make the material even
better at protecting armored vehicles from projectiles.
Courtesy of Tata Steel.