History

1930s was the first recorded period in timeline involving discovery of shape memory alloys. According to the book “Shape Memory Materials (first published in 1998, written by Otsuka and Wayman), A. Ölander discovered the psuedoelastic behavior of the Au-Cd alloy in 1932. Greninger Mooradian (1938) observed the formation and disappearance of martensitic phase at low and high temperatures of a Cu-Zn alloy. The basic phenomenon of the memory effect governed by the thermoplastic behavior of the martensitic phase was widely reported a decade later by Kurdjumov and Khandros (1949) and also by Chang and Read (1951).

In the late 1950s a researcher at the Naval Ordnance Laboratory named William J. Buehler developed Ni-Ti alloy which was durable enough to be used in nose cone of a missile. He named his discovery Nitinol (Nickel Titanium Naval Ordnance Laboratory). Buehler made up long, thin strips of Nitinol to demonstrate the material by bending it and proving that the strips would not break because they were durable and could be used in missiles. At a management meeting in 1961 at one of the demonstrations, which had been repeated many times until then, a strip of Nitinol was flexed by everyone at the meeting. One of the Associate Technical Directors, the late Dr. David S. Muzzey, heated the compressed Nitinol strip and witnessed that the strip stretched out its original shape.

Not only shape memory alloys but also shape memory polymers, which are also thermally-responsive materials, were developed in the late 1990s.