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Technology Database  Metallurgy THIN RIBBON OF SHAPE-MEMORY ALLOYS
Thin
Ribbon Of Shape-Memory Alloys
 Using the technology of rapid
melt solidification, the industrial production of a thin ribbon made of alloys
exhibiting the shape memory effect (SME) has been achieved for the first time.
The alloys were developed jointly with the Master Research сompanу.
The main feature of such alloys is their capability to change their shape, as
prescribed, depending upon the temperature, while at the same time producing a
considerable mechanical force. Thanks to the unique properties of SME alloys,
their applications are highly diverse continually expanding, primarily in
instrument-making, electrical engineering, aerospace technologies, medicine, and
minirobotics.
Thin ribbons of low-deformability
alloys based on titanium nickelide TiNi are not manufactured industrially by the
conventional method of ingot machining with sheet rolling because such a process
is both highly labor-intensive and expensive.
The principal advantages of the
STEMET thin ribbon, produced by the technology of rapid melt solidification,
derives from the formation of an amorphous or amorphous-crystalline structure in
it during the process of its manufacture; subsequent heat treatment produces a
submicrocrystalline structure 1-2 orders of magnitude less dispersed than that
of conventionally produced structures. It is this that slashes the time required
for the appearance of the SME by a factor of 5-10 and narrows thermal hysteresis
by a factor of 8-10. In physical and mechanical properties, moreover, the
rapidly hardened ribbon is superior to that produced from an ingot, and
throughout its length has a high plasticity and homogeneous SME properties.
Listed below are some of the
characteristics of the above SME-alloy ribbon:
-
thickness:
20-80 m m;
-
width:
0.5-20 mm;
-
length:
up to 200 m;
-
the temperature of SME appearance
varies from 0 to 200°C depending upon the composition of the alloy;
-
hysteresis:
2-8°C;
-
maximum reversible deformation
from 3 to 7% depending upon the type of deformation for a shape restoration
factor of 90-100%;
-
an SME-produced
force of up to 70 kg/mm.
The SME thin ribbon can be used
effectively in a variety of heat-sensitive devices employed as:
-
temperature indicators;
-
temperature relays, signaling devices in
industrial, domestic, railroad, and automobile fire alarms;
-
temperature-control devices in greenhouse,
grain-elevator, vegetable-storage, and warehouse thermostats;
-
transducers of liquid and gas overheating in
water-cooled radiators, in oil jackets cooling industrial transformers, in
heat exchangers, and steam boilers;
-
temperature-actuated switches for automobile
carburetors, ventilator fans and seat-warming systems;
-
heat-sensitive elements for controlling
technological processes.
Other highly promising
applications of SME thin ribbons include:
-
as actuators of light modulators in optical
data-processing systems;
-
as drives in heat engines and refrigerators;
-
as spirals for dilating small blood vessels in
medicine;
-
as damping materials and components of
composites;
-
as actuator mechanisms in various consumer goods
(thermometers, thermostats, toys, bijouterie, etc.);
An SME foil ribbon is now being
manufactured on an industrial scale. The designers and manufacturers of the
ribbon own the relevant know-how and certificates covering the composition of
the alloys, and the technology of the production of SME foil ribbon and of
temperature-sensitive devices based on it. A pilot production facility has been
organized to manufacture ribbon-based temperature relays and heat-sensitive fire
alarms.
We can provide supplies of thin
ribbon made from Master Research SME alloys and devices based on it.
Source: SciTecLibrary.ru
Publishing date: February 14, 2001
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