Ni-Ti shape memory alloys are extremely interesting materials both
for their ability of showing the shape memory effect (SME) and for
their elevated strength and ductility.
Shape memory alloys do exactly as their name would suggest; they're
metallic materials that are able to remember, and return to, their
original shape (the shape they are given when made, say as a
casting or an extrusion) under the right stimuli. The principle
behind this unusual phenomenon comes from two diverse atom
arrangements (crystal structures) present in this material - one at
high temperatures and one at low temperatures - that are
reversible.
At high temperatures, where one of the crystal structures is
favoured, the material can be shaped as desired and it retains this
geometry as it cools to lower temperatures. Cooled, the material
can be bent and twisted beyond all recognition of its previous
guise but, on heating, the low temperature atomic arrangement
reverts to its previous form and, in so doing, miraculously returns
to its previous shape.
1.Low Density and High Strength
2.Excellent Corrosion Resistance
3.Good resistance to effect of heat
4.Excellent Bearing to cryogenic property
5.Nonmagnetic and Non-toxic
6.Good thermal properties
Application:
Fire security and Protection systems: Lines that carry highly flammable and toxic fluids and gases must
have a great amount of control to prevent catastrophic events.
Systems can be programmed with memory metals to immediately shut
down in the presence of increased heat. This can greatly decrease
devastating problems in industries that involve petrochemicals,
semiconductors, pharmaceuticals, and large oil and gas boilers.
Golf Clubs: a new line of golf putters and wedges has been developed
using_____. Shape memory alloys are inserted into the golf clubs.
These inserts are super elastic, which keep the ball on the
clubface longer. As the ball comes into contact with the clubface,
the insert experiences a change in metallurgical structure. The
elasticity increases the spin on the ball, and gives the ball more
"bite" as it hits the green.
Helicopter blades: Performance for helicopter blades depend on vibrations; with memory
metals in micro processing control tabs for the trailing ends of
the blades, pilots can fly with increased precision.
Eyeglass Frames: In certain commercials, eyeglass companies demonstrate eyeglass
frames that can be bent back and forth, and retain their shape.
These frames are made from memory metals as well, and demonstrate
super-elasticity.
