Magnetic Shape Memory Alloys Wire
Main uses: fishing line,super elastic memory alloy mobile phone antennas,optical glasses frames, Bluetooth headsets, medical.
Nitinol shape memory alloy is a special alloy that can automatically restore its plastic deformation to its original shape at a certain temperature. Many scholars believe that the reason why the memory alloy can restore its original shape is due to the “memory factor”. The “memory factor” is derived through the study of the free energy of the phase transition process and the volume relationship.
It has good compatibility with human skin, so it can meet the needs of various engineering and medical applications and is an excellent functional material. In addition to its unique shape memory function, memory alloys also have excellent characteristics such as wear resistance, corrosion resistance, high damping and super elasticity.
Shape memory alloys can remember previously memorized shapes. .Plastically deform the nickel-titanium memory alloy in a low temperature environment, place the deformed material in a certain heat source, and when the temperature reaches the transition temperature from martensite to austenite, the material restores the shape before deformation, here A large force will be generated during the process. Therefore, it can be used as a driver in many different applications.
Superelastic shape memory alloys can exhibit the so-called mechanical shape memory effect or obvious superelastic elastic deformation characteristics. This deformation can be as high as 96 times the elastic strain of steel. Superelasticity is caused by the transformation from austenite stress-induced phase to martensite. After the stress is removed, it can be completely restored to its original state.
The so-called super-elasticity refers to the phenomenon that the sample produces a strain much larger than the elastic limit strain under the action of external force, and the strain can automatically recover when unloaded. That is, in the state of the parent phase, due to the effect of applied stress, the stress-induced martensite transformation occurs, so that the alloy exhibits a mechanical behavior different from that of ordinary materials, and its elastic limit is much greater than that of ordinary materials, and no longer observes the tiger. Law. Compared with shape memory properties, superelasticity does not involve heat. In a word, superelasticity means that the stress does not increase with the increase of strain within a certain deformation range. Superelasticity can be divided into linear superelasticity and nonlinear superelasticity. The stress-strain curve in the former is close to a linear relationship between stress and strain. Non-linear superelasticity refers to the results of stress-induced martensitic transformation and its inverse phase transformation during loading and unloading in a certain temperature range above Af. Therefore, nonlinear hyperelasticity is also called phase transition pseudoelasticity. The pseudo-elasticity of the nickel-titanium alloy can reach about 8%. The superelasticity of nickel-titanium alloy can be changed with the change of heat treatment conditions. When heated to above 400 ℃, the superelasticity begins to decrease.