Hastelloy Alloy special performance
Hastelloy Alloy in addition to its own basic performance, it also has a special performance, because it has its special performance, so widening its use. Closer to home, Hastelloy Alloy's special performance in general the following points:
I. the shape memory characteristics: shape memory is a certain shape of the mother phase from Af temperature above the cooling to Mf temperature below the formation of martensite, the martensite Mf below the temperature deformation, heated to Af below the temperature, with the reverse phase Change, the material will automatically restore its shape in the female phase. In fact, the shape memory effect is a heat-induced phase transition process of Hastelloy Alloy.
II. the corrosion resistance: Studies have shown that the corrosion resistance of nickel wire and stainless steel wire similar.
III. the superelasticity: the so-called superelasticity refers to the specimen under the action of external force is far greater than the elastic limit strain of the strain, the load can be automatically restored when the phenomenon. That is, in the matrix state, due to the role of external stress, resulting in stress induced martensitic transformation occurred, so Hastelloy Alloy show different from the ordinary material of the mechanical behavior, its elastic limit is much larger than ordinary materials, and no longer comply with Hooker's Law.
VI. the anti-toxicity: nickel titanium shape memory alloy special chemical composition, that is, this is a kind of nickel and titanium and other atomic alloys, containing about 50% of the nickel, and known nickel has carcinogenic and cancer-promoting effect. Under normal circumstances, the surface layer of titanium oxidation acts as a barrier, so that Ni-Ti alloy has good biocompatibility. The surface layer of TiXOy and TixNiOy can inhibit the release of Ni.
V. the temperature changes in the mouth Sensitivity: stainless steel wire and CoCr alloy orthodontic treatment of orthopedic wire is basically not affected by the temperature inside the mouth. Hastelloy Alloy The correction of orthodontic treatment of orthopedic filaments varies with the temperature of the oral cavity. When the amount of deformation is constant. The temperature increases, the correction force increases. On the one hand, it can accelerate the movement of the teeth, because the temperature changes within the mouth will stimulate the device due to the treatment of hair caused by delayed blood flow stagnation of blood flow, so that in the process of tooth movement to repair cells to be fully nutrient, Maintain its vitality and normal function. On the other hand, orthodontist doctors can not accurately control or measure the correction of oral environment.
VI. good shock absorption characteristics: due to chewing and night molars for the arch wire caused by the greater the vibration, the greater the damage to the root and periodontal tissue. Through the results of different archwire attenuation experiments, it was found that the amplitude of vibration of stainless steel wire was larger than that of super-elastic Hastelloy Alloy, and the initial vibration amplitude of superelastic nickel arch wire was only half of that of stainless steel wire. Good vibration and shock resistance of arch wire Health is very important, while the traditional arch wire such as stainless steel wire, there is a tendency to increase the absorption of the root.
VII. soft correction: the current application of dental orthopedic wire, including austenitic stainless steel wire, cobalt - chromium - Hastelloy Alloy wire, nickel - chromium alloy wire, the Australian alloy wire, gold alloy wire and titanium alloy wire. The load - displacement curves of these orthodontic corrected wires in tensile and three - point bending test conditions. Nickel-titanium alloy unloading curve platform is the lowest and most flat, indicating that it can provide the most lasting softening force.
