Exploration of shape memory function and application of medical nitinol spring tubing

1. Shape memory mechanism of nickel-titanium alloy spring tube
Nickel-titanium alloy, also known as Nitinol, is an intermetallic compound composed of nickel (Ni) and titanium (Ti). Its name is a combination of the English initials of these two elements and "alloy" (inol). One of the most striking properties of this alloy is its shape memory effect, that is, it can restore the previously set shape under certain conditions. The realization of this effect is mainly due to the phase transformation behavior of nickel-titanium alloy at different temperatures.

At low temperatures, nickel-titanium alloy presents a harder martensite phase; when the temperature rises above a certain critical value (austenite start temperature), it will transform into a softer austenite phase. It is this phase transformation process that enables nickel-titanium alloy spring tubes to deform when subjected to external forces and return to their original shape under appropriate temperature stimulation.

2. Manufacturing process of medical nitinol spring tubings
The process of manufacturing medical nitinol spring tubings is a precise and complex process. First, the raw materials are precisely processed and molded into a specific shape that meets medical needs. This step requires extremely high precision to ensure that the spring tube can function accurately in subsequent applications.

Subsequently, through the heat treatment process, the spring tube is placed in a specific temperature environment to stabilize its internal structure, that is, fixed to the required shape memory state. This process is the key to the realization of the shape memory function. It ensures that the spring tube is reversible as long as the temperature remains below the martensitic phase transition temperature after being subjected to external force, that is, it can restore its original shape under appropriate conditions.

3. Application process and advantages of medical nitinol spring tubings
medical nitinol spring tubings have been widely used in many medical fields due to their unique shape memory properties. For example, in the field of intravascular stents, stents made of nickel-titanium alloy spring tubes can be compressed at low temperatures, which is convenient for delivery into the body through catheters; once it reaches the lesion site and is heated to above the austenite start temperature, the stent quickly expands to the preset shape, effectively supporting the blood vessel wall and restoring blood circulation.

In addition, in the fields of dentistry, orthopedics, etc., nickel-titanium alloy spring tubes are also used to make correctors, implants, etc., using their shape memory properties to achieve precise positioning and adaptive adjustment, greatly improving the treatment effect and patient comfort.

In addition to the shape memory effect, Nitinol also has good biocompatibility, corrosion resistance and fatigue resistance, which enable it to remain stable when implanted in the body for a long time, reducing the risk of rejection and complications.