| In 1962 the shape memory effect is
discovered in NiTi alloys by the U.S. Naval Ordnance Lab. The
nominally equiatomic NiTi alloy was dubbed "Nitinol"
for Nickel Titanium Naval Ordnance Laboratory.
The first major application for the technology is launched
in 1971 by Raychem Corporation of Menlo Park, CA. The product
is a line of 3000 psi hydraulic couplings used to join titanium
tubing on the U.S. Navy / Grumman F-14A. Over 300,000 couplings
are put into service in this demanding application. Raychem
sold the couplings under the name Cryofit®.
The British Royal Navy specifies 6000 psi Cryofit couplings
for it's Trafalgar Class nuclear submarines in 1975. The U.S.
Navy begins using Cryofit on its surface ships in 1977. All
of these couplings utilize a cryogenic nickel-titanium-iron,
NiTiFe, alloy similar to Intrinsic's Alloy C. Raychem trademarks
the name Tinel® for its family
of nickel titanium alloys.
In 1974 Raychem begins production of Cryocon® electrical
connectors for use in the navigation system of the Trident missile.
These connectors utilize shape memory rings to compress split
cylindrical contacts onto mating pins. The Trident connector
has 16 contacts ganged together in a plastic housing. See UniLok
Application Examples for addition description. Cryocon connectors
are unique in offering signal and mechanical integrity in this
high shock and vibration environment. Cryocon connectors are
later used on missile, munitions and naval bulkhead feedthrough
applications, primarily in Europe.
In 1983 NiTiFe rings enter production for sealing metal caps
to plastic headers in the assembly of detonators for the UK
AWRE/ROF.
In the early 1980's Raychem develops a new nickel-titanium-niobium,
NiTiNb, alloy that offers similar performance to the cryogenic
alloy, but without the need to hold parts at cryogenic temperature
prior to installation. Intrinsic's Alloy H is similar to this
Raychem alloy. In 1985 Raychem launches its first major product
using the new alloy, Tinel-Lock®. This is
a family of NiTiNb rings used to terminate cable EMI/EMP shielding
braids. One of the first large programs to use Tinel-Lock is
the FMC Bradley Fighting Vehicle. Since that time, Tinel-Lock
has seen extensive usage in military and aerospace applications
including various satellite programs. See our Braid
Termination page for more information on
the application.
In 1988 NiTiNb rings enter production for the assembly of piezoelectric
accelerometers and in 1989 as drivers for 1/4 inch tube fittings
used on naval gage lines.
Beginning in 1989, NiTiFe rings are used in sonar towed arrays
to clamp polyurethane hose to fittings. Rings up to 5 inch diameter
are produced.
Beginning in 1990, NiTiNb rings are used to terminate metal
wiring conduit on civilian aircraft.
Raychem launches a standardized line of shape memory alloy
fastener rings in 1992 under the name UniLok. By 1993 the rings find uses
in a broad range of new applications including clamping a bundle
of optical components in a particle counter, sealing a cover
to a pressure sensor, joining aerospace valve components, retaining
a 10 inch diameter nuclear seal and providing a stop on a rocket
motor shuttle valve.
After pioneering the commercialization of NiTi shape memory
alloys for more than 20 years, in the early 1990's Raychem decides
to divest its shape memory metals division. Intrinsic Devices
purchases Raychem's shape memory fastener business, including
the UniLok product line, in 1994.
In the 50 years since their commercial introduction, shape
memory alloy fasteners have proven their reliability in a range
of demanding applications. Service lifetimes in excess of 30
years have been demonstrated. Their consistent response to static
loading, fatigue, high temperature exposure, thermal cycling
and general corrosion allow these fasteners to be confidently
engineered for new applications. Given continuing strides in
alloy production, metallurgy and manufacturing processes, use
of this technology is now spreading far beyond its military/aerospace
roots.
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