Memory alloys are widely used. For example, mechanical fastening pins, fittings, fire alarms, sockets and brazing of electronic instruments and equipment integrated circuits, artificial heart valves, vertebral correction rods, cranioplasty, oral and dental orthopedics, and mandibular restorations. It will also play a magical role in communications satellites, color TVs, temperature controllers and toys
In 1932, Schering-Plough of Sweden first observed the "memory" effect in gold-cadmium alloys, that is, when the shape of the alloy changed, once it heated to a certain jumping temperature, it could magically return to its original shape. This special-function alloy is called a shape memory alloy. The development of memory alloy has only been for more than 20 years, but due to its special role in various fields, it is attracting widespread attention in the world and is called "magic functional materials"
Early arrangement of patient dentition: Nitinol archwires are often used as the initial archwires in orthodontic systems due to the superelasticity and shape memory characteristics of the nickel-titanium archwires, and the low stress-strain curve. . I will greatly reduce. As there are several different straight wire correction technologies, MBT technology recommends using 0.016-inch heat-activated nickel-titanium arch wire (HANT wire), and DEMON self-locking bracket technology recommends using copper-containing heat-activated nickel-titanium arch wire. Wire (transition temperature is about 40 degrees), O-PAK technology recommends using a 0.016-inch superelastic nickel-titanium alloy arch wire for early alignment.
Hierarchical thermodynamics: increase the thermodynamic nickel-titanium alloy: TTR temperature is higher than oral temperature, about 40 degrees Celsius, so when the nickel-titanium arch wire is placed in the mouth, it is still in a multi-state, the arch wire is soft, and austenite transformation only occurs when the mouth contains heat The alarm will only be issued when water is present. Therefore, the orthodontic force is weak and can be used as the initial archwire for adult patients and periodontal patients. The copper-nickel-titanium wire produced by OMCRO and Japan's low-lag L-H nickel-titanium arch wire have this property.
Shape memory performance (sm) refers to the formation of martensite when the parent phase of a certain shape is cooled from above af temperature to below mf temperature, the martensite is deformed below the mf temperature, and then heated to below the af temperature, and then reversed The transformation causes the material to deform at a certain temperature. ll automatically restore its shape during the parent phase. Shape memory effect is actually a thermally induced phase transition process in nickel-titanium alloys
As early as the 1960s, scientists invented the nickel-titanium memory alloy, which deforms when heated and cooled, and quickly returns to the shape determined during the initial machining. Most alloys we are familiar with will change thousands of times in two lattice states, and even crack or even break. An expert from the University of Kiel in Germany explained in a paper that this is because there are more and more low-temperature phases (martensite) crystal structure in the high-temperature phase (austenite) of the metal. Incomplete transitions will cause the alloy to fracture. Published in the journal Science
A 52-year-old female patient with colon cancer underwent anus-preserving surgery with nickel-titanium pressure anastomosis ring (CAR) technology at a cancer hospital. After 10 days of rehabilitation, on November 22, her car smoothly fell off her body and was discharged from the body. This marks the success of the world's latest anastomosis technology in clinical applications. According to the Chinese and English full-text search, there is currently only one clinical report on the above-mentioned surgery in the world. This is also the first time that Nitinol pressure anastomosis ring technology is applied to such surgery in Asia