Shape memory alloys (SMAs) are special materials that can return to a predetermined shape when heated above a certain temperature. These alloys undergo a phase transformation, allowing them to "remember" their original form. Common examples of SMAs include nickel-titanium and copper-aluminum-nickel. When an SMA is deformed at a lower temperature, it can be reshaped. Upon heating, the material reverts to its original shape, making it useful in various applications, such as medical devices, actuators, and robotics. This unique property enables innovative designs and solutions in engineering and technology.