Description

Titanium based shape memory alloy:

Nitinol shape memory alloy is a kind of memory alloy developed earlier. Its shape memory effect is stable and relatively mature. This kind of memory alloy has been applied in various fields such as aerospace industry, energy, medical treatment, construction, automobile industry, electronic industry and human life. However, due to the expensive raw materials nickel and titanium, and the high processing cost, its application is limited.

Shape memory effect:

After a shape memory alloy with a certain initial shape is plastically deformed and fixed to another shape at a low temperature, the temperature is raised to a certain value by heating the alloy, and then the alloy recovers to its original shape. This effect is called shape memory effect, or SME shape memory effect for short. According to the shape recovery, it can be divided into one-way shape memory effect, two-way shape memory effect and full range memory effect.

Elastic effect:

When the shape memory alloy is subjected to an external force, it will undergo plastic deformation. After the external force is removed, the shape memory alloy will recover its original shape. This effect is called elastic effect. When shape memory alloy is elastically deformed, martensitic transformation will be induced, and when external force is removed, reverse martensitic transformation will occur.

Damping characteristics:

Shape memory alloys generate a large number of martensitic variants with the same structure and different orientations due to thermoelastic martensitic transformation, and the interface energy between the variants and the twin interface energy inside the martensite are very low, which are relatively easy to migrate, so that external mechanical energy such as vibration and impact can be effectively attenuated. Therefore, shape memory alloys have particularly good damping characteristics, and can be used as shockproof materials and silencing materials.

Resistance characteristics:

The research shows that for the nickel titanium alloy with the initial structure of martensite, there is a linear relationship between resistance and strain during the tensile process; for the nickel titanium alloy with the initial structure of austenite or a mixture of austenite and martensite, when the stress-induced martensitic transformation occurs, the slope of the curve will decrease, and the relationship between resistance and strain before and after the transformation remains linear.

Importance of Ni Ti shape memory alloy:

Nitinol shape memory alloy is a shape memory material with industrial practical value. It has good shape memory effect and elastic behavior, high mechanical properties, excellent wear and corrosion resistance, good damping characteristics, and good biocompatibility. The tensile strength of nickel titanium memory alloy is more than 1000MPa, the elongation is more than 20%, the damping characteristic is 10 times higher than that of ordinary springs, and its corrosion resistance is better than the current medical stainless steel. Therefore, it can meet the application needs of various projects and medicine. It is a very excellent functional material. Nickel titanium memory alloy has a wide range of applications, including electronics, machinery, aerospace, transportation, construction, chemistry, medical instruments Energy appliances and daily necessities.