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What is the role of medical nickel-titanium guidewires in medical devices?

Release Date:

17 Aug,2022

What is the role of medical nickel-titanium guidewires in medical devices? ?

Nickel-titanium alloy is a type of shape-memory alloy. Shape-memory alloys are special materials that can automatically recover from plastic deformation back to their original shape under certain conditions. Properties and characteristics of medical nickel-titanium guidewires, as well as their inherent qualities

As the name suggests, a medical nickel-titanium guidewire is a binary alloy composed of nickel and titanium. Due to changes in mechanical stress, it exhibits two distinct crystal phases: austenite and martensite. The sequence of phase transformations in the nickel-titanium alloy during cooling is from the parent phase. ( Austenitic phase )- r Appearance - Character. R The phase is菱形-shaped, and austenite is the state at high temperatures. ( Higher than the austenite start ) , or the state when deactivation is removed by external forces—cubic, rigid, and stable. The phase is relatively low. ( Less than Mf: The Ending ) Or load ( Activated by external force ) , hexagonal, ductile, repetitive, somewhat unstable, and more prone to deformation.

The special properties of medical nickel-titanium guidewires

1. Memory : When a certain primary phase from Af The above cooled to Mf The following forms when, Mf The following transformation, heat it to Af The following: Through the reverse process, the material automatically returns to its original phase. In fact, the shape-memory effect is a thermally induced phenomenon in nickel-titanium alloys. Therefore, at this point, we can observe that the product swiftly reverts to its previous state, eliminating any concerns about deformation. Thanks to this remarkable property, the product can be seamlessly integrated into the patient's body without worrying about deformation or other potential health issues. As a result, it can be used with complete peace of mind.

2. The so-called phenomenon refers to when a specimen experiences strain far exceeding its ultimate strain under external force, yet automatically recovers its strain energy upon unloading. Specifically, in the parent phase, stress-induced deformation causes the alloy to exhibit mechanical behavior distinctly different from that of conventional materials—its ultimate strength is significantly higher, no longer adhering to Hooke's Law. Unlike shape-memory effects, this behavior is independent of temperature. In essence, within a certain range of deformation, stress does not increase with increasing strain; instead, it can be categorized into linear and nonlinear responses. In the former case, the stress - In the strain curve, stress - The strain relationship is nearly linear. Nonlinearity occurs at Af During the loading and unloading process within the aforementioned range, stress-induced effects and their corresponding responses occur—this is why nonlinearity is also referred to as "pseudo." The pseudo-effect of medical nickel-titanium guidewires can reach up to 8% Left and right. The behavior of medical nickel-titanium guidewires changes depending on the heat treatment conditions. When heated beyond… 400 At ℃, it begins to drop. Stainless steel wire and CoCr Orthodontic forces from alloy wires remain unaffected by the oral environment. In contrast, orthodontic forces from high-nickel-titanium wires fluctuate in response to changes within the mouth.