Is nitinol a shape memory alloy?
Nitinol, a nearly equiatomic nickel–titanium shape memory alloy, has wide applications in cardiovascular stents, micro-actuators, and high damping devices . The microstructure characteristic of Nitinol is that it is in a martensitic phase at lower temperatures, but in an austenitic phase at elevated temperatures.
How does nitinol remember its shape?
Shape memory is the ability of a part made from nitinol to undergo deformation at one temperature and then return to its original shape, undamaged, when heated above its “transformation temperature.” Superelasticity occurs within a few degrees just above the transformation temperature, at which point nitinol exhibits …
What can shape memory polymer be used for?
Because shape memory polymers can respond to temperature, light, pH and moisture, there are many very interesting possibilities for these materials in fabrics. These include comfort, aesthetics, wound monitoring, protection against environmental conditions, smart controlled drug release, and more.
Is Nitinol a polymer?
1 Introduction. Coating of Nitinol (NiTi) surface with a polymer layer has become very appealing in the past few years as it has become one of the most attractive metal alloy materials for biomedical applications.
What are the different types of Nitinol?
There are two primary types of Nitinol: superelastic and shape memory, which are determined by transformation temperature. Superelastic Nitinol is cooler, and shape memory Nitinol is warmer.
What is special about Nitinol?
Nitinol is a metal alloy of nickel and titanium that boasts special properties, including superelasticity and pseudoelasticity (shape memory). Nitinol will return to its original shape when it’s heated up. It can also withstand extreme stress without changing shape.
Why is nitinol a shape memory alloy?
Nitinol acts as a super spring through the Superelastic effect. Superelastic materials undergo stress-induced transformation and are commonly recognized for their “shape-memory” property. Due to its superelasticity, NiTi wires exhibit “elastocaloric” effect, which is stress-triggered heating/cooling.
Is nitinol a polymer?
What is Nitinol made from?
Nitinol is a metal alloy of nickel and titanium with unique properties, including superelasticity or pseudoelasticity and “shape memory” properties. That means nitinol can remember its original shape and return to it when heated.
How is Nitinol used?
Nitinol wires are used in model heat engines made for demonstration purposes. This material is used in temperature controls. Its shape changing properties can be used for activating a variable resistor or a switch for controlling the temperature. This metal is often used in mechanical watch springs.
What are the advantages of Nitinol?
The wire is resistant to corrosion, much like other types of metals used in this field, such as titanium or stainless steel. NiTinol does provide biocompatibility, which means that for most people our bodies will not react adversely to the wire when it is used.
What materials are used to make shape memory?
These will be made of a shape memory alloy like nitinol or a copper-aluminum-nickel alloy. Though the transition temperature change in nitinol is fantastical, it’s most commonly used for its superelastic mechanical properties – unrivaled in its ability to hold a shape.
What are the benefits of nitinol being discovered relatively recently?
One of the greatest benefits of nitinol being discovered relatively recently is that the interest provoked by publicity pulled in a great deal of researchers. This also happened at a time when computers and scientific instrumentation were sufficient for the task. As a result, there is a cache of digitized scientific papers on the alloy.
What is the chemical structure of nitinol?
With proper heat treatment, nitinol can be formed and set with its atomic crystal lattice of nickel and titanium in the body-centered cubic (austenite) structure. This is where the metal will snap back to when warmed.
What is a nitinol motor?
Like wax motors, nitinol is heat-activated and can perform mechanical work without electrical systems involved. This works well for thermally actuated valves, linear actuators, various types of mechanical triggers, sensors and indicators.