Memory Alloy Principle: Memory alloys are generally thought to have shape recovery memories when they are transformed from complex rhomboid crystal structures into simple cubic crystal structures. When the memory alloy is restored to its original shape, it is accompanied by great force, and the nickel-titanium alloy is as high as 60 kg square mm, which is much larger than the force added at the time of initial deformation. In general, up to ten times the original deformation, which means that the output energy is much larger than the input energy. Scientists can not explain this. Physicist Luoshaer said: "There is nothing wrong with the laws of thermodynamics, but these laws are not suitable for nickel-titanium? ". At present, many scholars believe that the reason why memory alloys can restore their original shape is due to the role of "memory factors." The "memory factor" is derived from the study of the free energy of the phase transition process and the volume relationship.