Project Title:

Digital Storage Device Using Thin-Film, Shape-Memory Alloy

06.07-4109
Digital Storage Device Using Thin-Film,
	Shape-Memory Alloy
TiNi Alloy Company
1144 65th Street, Unit A
Oakland, CA 94608
A. David Johnson  (415-658-3172)
ARC -- NAS2-12797

Abstract:

	 The need for high-volume, high-speed digital data recording, storage, and retrieval
systems is growing rapidly. Magnetic media technology is approaching its practical
limits of capacity while existing work on optical media seems to be limited to magneto-optical
and WORM (Write Once, Read Many times) technology. There is a clear need to increase
the speed and capacity of mass storage systems, not only for routine science, engineering,
and business systems, but for existing and future supercomputers.
	This innovation applies a thin film of shape-memory alloy such as Nitinol (nickel-titanium
alloy) as a medium for high-density, non-volatile, read-write digital information
storage. Small domains (approaching one micron in diameter) of shape-memory alloy
are selectively heated by fast, high-intensity, light pulses, causing the domains
to change their angle and/or amount of reflectance. Readout is accomplished by detection
of reflected pulses of light of lower intensity from the small domains.
	Phase I clearly demonstrated the feasibility of sputtering micron-thick Ni-Ti film
which can be annealed to induce the shape memory property. Free-standing beams of
Ni-Ti film down to 5 microns thick displayed the mechanical shape memory effect when
bent in the cold state and allowed to warm. Experimentation with loads on the end
of the beam indicate recovery stresses of approximately 70 ksi. In effect, this work
has shown conclusively that the shape memory effect can be produced in sputter-deposited
films of nickel-titanium.

Potential Commercial Application:

Potential Commercial Application: If successful, this technology will be widely used
by defense, space, and commerce. "Spin-off" to the growing field of micro-mechanical
actuators will generate a secondary market.