Original Title: TiNi-SS NiTi Ribbon Superelastic Introduction of nickel-titanium alloy NiTi alloy is a kind of shape memory alloy, which is a special alloy that can automatically restore its original shape at a specific temperature after plastic deformation. Its expansion ratio is more than 20%, its fatigue life is up to the seventh power of 110, its damping characteristic is 10 times higher than that of ordinary springs, and its performance is superior to that of current medical stainless steel, so it can meet the application needs of various engineering and medicine, and it is a very functional material. In addition to the shape memory function, shape memory alloy also has the characteristics of loss, corrosion resistance, high damping and superelasticity. Standard: Q/XB1516 Q/XB1520 Grade: TiNi-01 phase transition temperature: 20 ? -40 ?; TiNi-02 phase transition temperature: 45 ? -90 ?; TiNi-SS phase change temperature: 5 ? -15 ?, TiNi-03 phase change temperature lt; 5 ?; TiNi-YY phase transition temperature: 33 ? ± 3 ?; TiNiCU phase transition temperature: As-Ms ? 5 ?; TiNiNb phase change temperature: As-Ms < 150 ? Physical properties of nickel-titanium alloy: tensile strength: 850MPa; yield strength: 195 ~ 690MPa; elongation: 25 ~ 50% Chemical composition of nickel-titanium alloy memory wire: Ni: 55.4% -56.2%, C = 0.07, H = 0.005, O = 0.050, N = 0.05 TiNi shape memory alloy (SMA) is a kind of functional material. Besides its high specific strength, corrosion resistance, nonmagnetism and good biocompatibility, it also has unique shape memory properties and mechanical properties. It is used in aerospace, communication, medical treatment, automatic control, instrumentation, pipeline connection, glasses manufacturing and daily life. The comprehensive performance of TiNi shape memory alloy produced by Yhan Metal has reached the international level, and enjoys a high reputation in the domestic medical equipment, glasses manufacturing, mobile phone antenna and other industries. Performance characteristics of nickel-titanium alloy Phase Transformation and Properties of Nickel-Titanium Alloy As its name imply, nitinol is a binary alloy composed of nickel and titanium, which has two different crystal structure phase, namely austenite phase and martensite phase, due to that change of temperature and mechanical pressure. The transformation sequence of NiTi alloy during cooling is parent phase (austenite phase)-R phase-martensite phase. The R phase is rhombohedral, and the austenite is cubic and hard when the temperature is higher (greater than the temperature at which the austenite starts), or when the load is removed (Deactivation). The shape is relatively stable. The martensite phase, on the other hand, is at a relatively low temperature (less than Mf: the temperature at which martensite ends) or when loaded (activated by an external force), hexagonal, ductile, repetitive, less stable, and more deformable. Special Properties of Nickel-Titanium Alloy . Shape memory properties (Shape memory) When the parent phase of a certain shape is cooled from above the Af temperature to below the Mf temperature to form martensite, the martensite is deformed below the Mf temperature and heated to below the Af temperature. With the reverse phase transformation, the material will automatically restore its shape in the parent phase. In fact, the shape memory effect is a thermally induced phase transformation process in NiTi alloys. Superelastic The so-called superelastic refers to the phenomenon that the specimen produces a strain far greater than the elastic limit strain under the action of external force, and the strain can be automatically restored when unloaded. That is to say, nickel titanium wire , in the parent phase state, due to the external stress, the stress-induced martensite transformation occurs, so the alloy shows different mechanical behavior from ordinary materials, its elastic limit is far greater than that of ordinary materials, and it no longer obeys Hooke's law. In contrast to shape memory properties, superelasticity is not thermally involved. In a word, hyperelasticity means that the stress does not increase with the increase of strain within a certain range of deformation, which can be divided into linear hyperelasticity and nonlinear hyperelasticity. In the stress-strain curve of the former, the relationship between stress and strain is nearly linear. Nonlinear hyperelasticity is the result of stress-induced martensitic transformation and its reverse transformation during loading and unloading in a certain temperature range above Af, so nonlinear hyperelasticity is also called phase transformation pseudoelasticity. The phase transformation pseudoelasticity of NiTi alloy can reach about 8%. The superelasticity of nitinol varies with the conditions of heat treatment, and begins to decrease when the archwire is heated above 400 oC. Expand the full text Sensitivity to temperature changes in the oral cavity: The orthodontic force of stainless steel wire and CoCr alloy orthodontic wire is basically not affected by the temperature in the oral cavity. The orthodontic force of the superelastic NiTi alloy orthodontic wire varies with the oral temperature. When the deformation is constant. The orthodontic force increased with the increase of temperature. On the one hand, it can accelerate the movement of teeth, because the temperature change in the oral cavity will stimulate the blood flow in the blood stasis area caused by the capillary stagnation caused by the orthodontic device, so that the repair cells can be fully nourished during the movement of teeth to maintain their vitality and normal function. On the other hand, the orthodontist cannot control or measure the orthodontic force in the oral environment. Corrosion resistance: Studies have shown that the corrosion resistance of nickel-titanium wire is similar to that of stainless steel wire. Resistance to toxicity: The chemical composition of nickel-titanium shape memory alloy, that is, it is an equiatomic alloy of nickel and titanium, containing about 50% nickel, which is known to have carcinogenic and carcinogenic effects. In general, the surface layer of titanium oxide acts as a barrier, which makes the Ni-Ti alloy have good biocompatibility. TixOy and TixNiOy in the surface layer can inhibit the release of Ni. Gentle orthodontic force: Current commercial orthodontic wires include austenitic stainless steel wire, cobalt-chromium-nickel alloy wire, nickel-chromium alloy wire, Australian alloy wire, gold alloy wire and ß-titanium alloy wire. Load-displacement curves for these orthodontic wires under tensile and three-point bending test conditions. The plateau of the unloading curve of the nickel-titanium alloy is also flat, indicating that it can provide a lasting and gentle orthodontic force. Good shock absorption characteristics: The greater the vibration of the arch wire caused by chewing and bruxism, the greater the damage to the root and periodontal tissue. Through the study on the attenuation experiment of different archwires, it is found that the vibration amplitude of stainless steel wire is larger than that of superelastic nickel-titanium wire, and the initial vibration amplitude of superelastic nickel-titanium archwire is only half of that of stainless steel wire. Good vibration and shock absorption characteristics of archwires are very important for the health of teeth, while traditional archwires such as stainless steel wires tend to aggravate root resorption. Yehan Industry (Shanghai) Co., Ltd. is a high and new technology production enterprise which integrates smelting, development and production of high temperature alloy, high nickel alloy, nickel alloy, corrosion-resistant alloy, Inconel alloy, Monel alloy and various special alloy materials. Products include pipes, bars, plates, wires, strips, flanges, forgings and pipe fittings. Products are used in petrochemical, aerospace, shipbuilding, energy, chemical industry,Titanium 6Al4V wire, electronics, environmental protection, machinery and instrumentation and other fields. (13-6-81-71-31-45zx) Return to Sohu to see more Responsible Editor:. yunchtitanium.com