A Shape Memory Alloy (SMA) is able to memorize
and retrieve its original state. Thus, after it has been deformed by heating
above their transformation temperature. Shape Memory Effect (SME) is known for
this unique effect of returning to an original geometry after a large inelastic
deformation.
The SME had already found in 1932 and until 1971 it was believed that be
common to all alloys undergoing thermo elastic martensitic transformations.
Many alloys exhibiting SME found, and still are making great efforts to
discover new materials. These alloys, however, only two systems, CuZnAl, NiTi
alloy, and combinations with minor amounts of other elements are currently
commercially important. Other alloys are poorly adapted to industrial
production, either because the constituent elements are too expensive or they
cannot be used unless. They are in the form of single crystals. NiTi-based SMA
are more preferable for most applications. However, each material has its own
advantage to customize or applications.
If there is an alternative material to conventional actuators such as
hydraulic, pneumatic and motor based systems; it would lead to peerless
perfection in the history. A shape memory alloy is a lightweight, solid state
alloy that remembers its original shape and that when deformed returns to its
pre-deformed shape when heated. Industrial applications of shape memory alloys
can be identified including automotive, aerospace, bio-medical and robotics.
