Memory alloys are widely used. For example, mechanical fastening pins and pipe joints, welding of fire alarms, connectors and integrated circuits on electronic instruments and equipment, artificial heart valves, massage sticks, cranioplasty, orthodontics and jaw restoration in medical treatment, etc. It will also play a magical role in communication satellites, color TVs, thermostats and toys, and will also become a new material memory alloy in modern navigation, aviation, aerospace, transportation, textiles and other fronts. It has been used in pipeline combination and automatic control. Bushing made of memory alloy can replace welding. The method is to expand the inside of the pipe end by about 4% at low temperature, and put them together when assembling. Once heated, the bushing will shrink back to its original shape and form a tight bond. There are 6,543,800 such joints used in the hydraulic system of American Navy aircraft, and there has been no oil leakage or damage for many years. It is very convenient to repair damaged pipelines of ships and submarine oil fields with memory alloy fittings. In some inconvenient parts, the pin is made of memory alloy, put into the hole and heated, and the tail automatically curls separately to form a single-sided assembly.

Memory alloy is especially suitable for thermal machinery and constant temperature automatic control. The ventilation window can be opened in sunny days and closed automatically when the room temperature drops at night. There are also many design schemes of memory alloy heat engine, which can work between two kinds of media with small temperature difference, opening up new ways for the utilization of industrial cooling water, nuclear reactor waste heat, ocean temperature difference and solar energy. At present, the common problem is low efficiency, only 4% ~ 6%, which needs to be further improved. The application of memory alloy in medical treatment is also very eye-catching. For example, the bone plate used for fracture can not only fix two broken bones, but also produce compressive force in the process of restoring to the original state, forcing the broken bones to join together. Dental orthodontic wires, long clips for ligating cerebral aneurysms and vas deferens, and stents for straightening the spine are all started by body temperature after being implanted in the human body. Thrombotic filter is also a new product of memory alloy. After the straightened filter is implanted in a vein, it will gradually return to a network, thus preventing 95% of blood clots from flowing to the heart and lungs.

Artificial heart is an organ with more complicated structure. Muscle fibers made of memory alloy can imitate the contraction movement of ventricle by cooperating with elastic membrane ventricle. Now the pumping has been successful.

Because memory alloy is a kind of "living alloy", various automatic control devices can be designed by using its shape change at a certain temperature, and its application field is expanding constantly. At present, shape memory effect and superelasticity have been widely used in various fields of medicine and life. Such as making thrombus filters, spinal orthopedic rods, bone plates, artificial joints, women's bras, artificial hearts and so on. But also can be widely used in various automatic control devices. Shape memory films and filaments may become ideal materials for future subminiature manipulators and robots. Especially its light weight, high strength and corrosion resistance make it popular in various fields. .

A pre-made "ice" nickel-titanium alloy can be restored to its original shape as long as it is soaked in hot water after being accidentally pulled out.

An alloy in which nickel and titanium are mixed in half to form a prefabricated shape, and this shape can be maintained permanently after being forged slowly for ten minutes at a high temperature of 400 degrees Celsius (at this time, it is called the austenitic morphology of high-temperature phase Vostian iron state).

The main reason is that when its crystallization is slowly heated, each metal atom will have enough time to fill each gap. At this time, its arrangement and combination are the most compact, and the commercial name of this alloy solid is memory alloy. If the memory alloy is deformed due to any external factors (the configuration that can be twisted and deformed at will is called martensite), that is, crystal cavities are generated, and the cavities can be filled up by heating slightly above the phase transition temperature, that is, the original state can be restored. This process is called shape memory.

Shape memory metal spinal orthopedic internal fixator