What is nitinol made of?
Nitinol is an alloy that is made up of mostly Nickel and Titanium. We take advantage of two primary unique properties with Nitinol, especially with medical devices—shape memory and superelasticity.
What happens to the shape of nitinol when heated?
However, when heated through its transformation temperature it reverts to Austenite and recovers its previous shape. The temperature at which Nitinol remembers its high-temperature form can be adjusted by slight changes in the alloy composition and through heat treatment.
Why did it take so long to develop nitinol?
While the potential applications for nitinol were realized immediately, practical efforts to commercialize the alloy did not take place until a decade later. This delay was largely because of the extraordinary difficulty of melting, processing and machining the alloy.
Can you make nitinol ingot from titanium?
Most metals can be melted in a furnace and cast into an ingot without a problem. If you’re interested in doing this, there are plenty of plans online to build a melting furnace for as little as $10. Unfortunately, the combustion temperature of titanium is lower than its melting point. Due to this, nitinol ingot must be prepared in a vacuum.
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How is nitinol formed?
Nickel titanium, also known as Nitinol, is a metal alloy of nickel and titanium, where the two elements are present in roughly equal atomic percentages. Different alloys are named according to the weight percentage of nickel; e.g., Nitinol 55 and Nitinol 60.
What metals are used to make nitinol?
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 a shape set into nitinol?
The shape setting of the nitinol occurs when the metal is annealed in the range of 500 - 550 ˚C. A fixture is used to restrain the wire at this temperature to establish the austenitic or 'set' shape. The fixture and wire are held at this temperature briefly and then quenched or rapidly cooled in air.
Why was nitinol created?
In the process of creating a corrosive resistant alloy, they created a Shape Memory Alloy (SMA) made of 55% nickel and 45% titanium. This new material was relatively inexpensive and much safer (non-toxic) than previous SMA's. The team named their new alloy Nitinol (pronounced night-in-all).
Who makes nitinol?
Norman Noble provides complete, single-source contract manufacturing of nitinol medical implants and devices made from superelastic and shape-memory nitinol.
Can Nitinol stop a bullet?
A 1mm thick sheet of nitinol safely stopped a 7.62mm bullet. Temperature Control: Nitinol is thermally active. That means that the nitinol actuator can double as a sensor, opening valves when temperatures reach desirable (or unsafe) levels.
Why is Nitinol expensive?
Nitinol is an especially valuable alloy because it is extremely elastic and can change shape depending on temperature. This means that when Nitinol is cool (martensitic), it is bendable and exceptionally soft, and when it is warm (austenitic), it is rigid and super elastic.
Can you make a knife out of nitinol?
The SM-100 brand of Nitinol, like its forerunner, is extremely tough. While a typical sanding belt can be used to grind several typical, mono-steel knife blades, it requires several belts, in many cases six or more, for the same process using the SM-100 alloy.
Does nitinol have memory?
Nitinol (pronounced night-in-all) is a metal alloy with unique properties and uses. This amazing metal alloy can “remember” or change shape depending on temperature.
Why does nitinol remember its shape?
However, when the alloy is heated through its transformation temperatures, it reverts to austenite and recovers its previous shape with great force. This process is known as shape memory.
Is Nitinol environmentally friendly?
Nitinol engines have been demonstrated to run continuously for over a year with no degradation and have very little impact on the environment throughout their life-cycle, making them a truly green energy source.
How long can Nitinol last?
Nitinol is stable against permanent temperature-induced metallurgical changes as long as the exposure temperature is less than the annealing or aging temperatures. For the SE508 alloy, the aging temperature range is 200ºC-500ºC. Nitinol products have infinite shelf life under normal conditions.
How much does Nitinol cost?
The price is steep, however: a pair costs more than $200. Indeed, the relatively high cost of nitinol has led some manufacturers to use cheaper, copper-based alloys. Nickel-titanium alloys cost about $11 a pound; copper-zinc-aluminium alloys cost about $1 a pound.
Is Nitinol toxic?
Despite the higher initial nickel dissolution, Nitinol induced no toxic effects, decrease in cell proliferation, or inhibition on the growth of cells in contact with the metal surface.
What are 3 properties of Nitinol?
Nitinol physical propertiesMelting point1300 deg. C (2370 deg. F)Density6.45 g/cu.cm (0.233 lb/cu.in)Thermal conductivityaustenite0.18 W/cm * deg. C (10.4 BTU/ft * hr * deg. F)martensite0.086 W/cm * deg. C (5.0 BTU/ft * hr * deg. F)Coefficient of thermal expansionaustenite11.0E-6/deg. C (6.11E-6/deg. F)3 more rows
Can you 3D print Nitinol?
The NUS team developed and demonstrated super elastic (shape memory effect) Nitinol stents through novel designs manufacturable by 3D printing (i.e. SLM), one of the world's earliest inventions in the medical field.
What are 3 properties of nitinol?
Nitinol physical propertiesMelting point1300 deg. C (2370 deg. F)Density6.45 g/cu.cm (0.233 lb/cu.in)Thermal conductivityaustenite0.18 W/cm * deg. C (10.4 BTU/ft * hr * deg. F)martensite0.086 W/cm * deg. C (5.0 BTU/ft * hr * deg. F)Coefficient of thermal expansionaustenite11.0E-6/deg. C (6.11E-6/deg. F)3 more rows
Is there nickel in nitinol?
Nickel is a common allergen in patients with contact dermatitis and is the predominant component of nitinol.
Does nitinol have Cobalt?
NiTi #3 is a ternary grade of Nitinol containing additions of cobalt (1.0-2.0% Co by weight) and is often used to maximize loading and unloading plateau stresses over other Nitinol grades. Decreased transformation temperatures also allow this grade of Nitinol to remain superelastic in colder temperature applications.
What are the disadvantages of nitinol?
Generally speaking, nitinol is expensive, and difficult to process and machine. But its unique properties, such as superelasticity, shape memory, biocompatibility and fatigue resistance, make it essential for medical applications. For some applications, therefore, it is the only possible solution.
How is nitinol made?
How is nitinol made? Most metals can be melted in a furnace and cast into an ingot without a problem. If you’re interested in doing this, there are plenty of plans online to build a melting furnace for as little as $10. Unfortunately, the combustion temperature of titanium is lower than its melting point. Due to this, nitinol ingot must be prepared in a vacuum. But, not just any vacuum, it must be prepared in high vacuum because just a few oxygen and nitrogen atoms in the matrix will dramatically reduce the properties of the nitinol.
How to turn nitinol into material?
The first step in transforming nitinol ingot into material that can be used for practical purposes is to hot roll it . As a general rule, higher temperatures allow the material to be formed much more easily while cooler temperatures result in less tool wear and less contamination from atmospheric factors.
Why is nitinol hard to cold work?
First, the superelasticity causes the nitinol to regain most of the plastic deformation imparted by the roll or die. Second, nitinol can only withstand 30-40% reduction in cross sectional area, so it must be annealed frequently.
Why do you need to prepare nitinol ingots in vacuum?
But, not just any vacuum, it must be prepared in high vacuum because just a few oxygen and nitrogen atoms in the matrix will dramatically reduce the properties of the nitinol.
What is the process of melting nitinol?
While there are several processes for melting the nitinol ingot in vacuum, the two most common ones are vacuum induction melting (VIM) and vacuum arc remelting (VAR). VIM offers great process control because the induction frequencies can be used to stir the molten metal, ensuring consistency throughout the ingot.
What are the different types of transitions between nitinol soaks?
There are effectively four types of transitions between soaks: water quench, oil quench , air cool, and ramping. Water quench is the most commonly used transition and is accomplished by immersing the part in water.
What temperature to anneal nitinol?
Generally speaking, temperatures 450-600℃ (840-1,100℉) can be used to set the shape by annealing while aging at temperatures 300-500℃ (575-950℉) are useful for adjusting the transition temperature. A quick note: even if you have a high quality muffle furnace, equipped with a digital PID controller measuring temperature to 1℃, the area surrounding the door is substantially cooler than the rest of the furnace. This will result in the nitinol in this area having substantially different properties from the nitinol in the rest of the cook. At Kellogg’s Research Labs, it is our recommendation that you leave a 1” (2.5cm) gap between the door and your first nitinol sample.
How is Nitinol Manufactured and Processed?
Different recipes of the nitinol alloy can alter the temperature at which the martensite-austenite transition occurs. The balance is nearly 50/50 Nickel and Titanium with small changes in the ratio having a large impact on the transition temperature.
Who invented the nitinol engine?
Researcher Ridgeway Banks went to task on this in 1973 when he built the first nitinol engine. It relied on moderately solar-heated water to drive the temperature transition in nitinol wires and outputted a rotational powered shaft for use in any manner of machinery.
What is a Nitinol Engine?
If the concept of a nitinol engine didn’t initially bring you here, your mind might have already strayed to this.
How many revolutions does nitinol take to break glasses?
While nitinol can be used for those nearly indestructible glasses frames, they do have a limit. A typical car engine runs between 500-5,000 revolutions each minute. If you’d bend your glasses as often as nitinol would be bent in a cycling engine they’d break too.
How to get nitinol wire to spring back?
Then when you pick it up and toss it into a bowl of hot water, it will immediately spring right back out to its original straight shape with stunning speed and force.
What happens to crystalline structure as it cools?
As it cools, the crystalline structure rearranges to a face-centered cubic (martensite) structure without changing its outward shape.
Is nitinol a martensitic or austenitic?
Austenitic structures are body-centered cubic and martensitic structures are face-centered cubic. 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 does the name Nitinol mean?
The "Ni" and "Ti" are the atomic symbols for nickel and titanium. The "NOL" stands for the Naval Ordinance Laboratory where it was discovered.
What is SMA made of?
At the time the scientific team were trying to develop a heat and corrosive resistant alloy. In the process of creating a corrosive resistant alloy, they created a Shape Memory Alloy (SMA) made of 55% nickel and 45% titanium. This new material was relatively inexpensive and much safer (non-toxic) than previous SMA's.
What temperature is superelastic nitinol?
Superelastic Nitinol is commonly used in medical devices. Transformation temperatures for superelastic grades are between -20°C and 22°C [-4°F and 71.6°F]. Shape memory Nitinol is commonly used for actuators and other industrial applications.
What is nickel and titanium?
Known for its unique superelastic and shape memory properties - the ability to remember and return to a specified shape after deformation when exposed to a predetermined temperature - this alloy is revolutionizing the way the medical device and other high-performance industries manufacture next-generation solutions.
What magnification does stainless steel have?
Etched and mechanically polished chemical removal of oxide layer followed by mechanical polish - surface will have stainless steel appearance although at > 40x magnific ation micro scratches are present
Is nitinol a round wire?
Determining which grade of Nitinol is right for your application is only part of the equation. If you need Nitinol as basic round wire, that's exactly what you'll get, but there are many more options to maximize device design.
Is nitinol cooler than shape memory?
Superelastic Nitinol is cooler, and shape memory Nitinol is warmer. Don't let the description fool you - the same superelastic and shape memory effect is taking place regardless of category. To help you pick the Nitinol that is best for your application, at Fort Wayne Metals, we divide the categories of superelastic and shape memory ...
Where did the word "nitinol" come from?
The word Nitinol is derived from its composition and its place of discovery: ( Ni ckel Ti tanium- N aval O rdnance L aboratory). William J. Buehler along with Frederick Wang, discovered its properties during research at the Naval Ordnance Laboratory in 1959. Buehler was attempting to make a better missile nose cone, which could resist fatigue, heat and the force of impact. Having found that a 1:1 alloy of nickel and titanium could do the job, in 1961 he presented a sample at a laboratory management meeting. The sample, folded up like an accordion, was passed around and flexed by the participants. One of them applied heat from his pipe lighter to the sample and, to everyone's surprise, the accordion-shaped strip contracted and took its previous shape.
Why is nitinol so difficult to make?
Nitinol is exceedingly difficult to make, due to the exceptionally tight compositional control required, and the tremendous reactivity of titanium. Every atom of titanium that combines with oxygen or carbon is an atom that is robbed from the NiTi lattice, thus shifting the composition and making the transformation temperature that much lower. There are two primary melting methods used today:
How does heat treatment work on nitinol?
Heat treating nitinol is delicate and critical. It is a knowledge intensive process to fine-tune the transformation temperatures. Aging time and temperature controls the precipitation of various Ni-rich phases, and thus controls how much nickel resides in the NiTi lattice; by depleting the matrix of nickel, aging increases the transformation temperature. The combination of heat treatment and cold working is essential in controlling the properties of nitinol products.
What is the ability of nitinol to undergo deformation at one temperature?
Shape memory is the ability of nitinol to undergo deformation at one temperature, stay in its deformed shape when the external force is removed, then recover its original, undeformed shape upon heating above its "transformation temperature".
Why did nitinol take so long to commercialize?
This delay was largely because of the extraordinary difficulty of melting, processing and machining the alloy. Even these efforts encountered financial challenges that were not readily overcome until the 1980s, when these practical difficulties finally began to be resolved.
What is nitinol 0.33?
0.33. Nitinol properties are particular to the precise composition of the alloy and its processing. These specifications are typical for commercially available shape memory nitinol alloys.NITINOL. Nickel titanium, also known as Nitinol, is a metal alloy of nickel and titanium, where the two elements are present in roughly equal atomic percentages.
What is the temperature of nitinol?
Transformation temperatures in nitinol can be controlled to some extent, where A f temperature ranges from about −20 °C to +110 °C. Thus, it is common practice to refer to a nitinol formulation as "superelastic" or "austenitic" if A f is lower than a reference temperature, while as "shape memory" or "martensitic" if higher. The reference temperature is usually defined as the room temperature or the human body temperature (37 °C; 98 °F).
How does Nitinol work?
How it Works – Developing a Good Memory: Nitinol Shape Memory Alloy. It’s expensive and hard to machine, but Nitinol is perfect for applications that require one or more of its special qualities: superelasticity, shape memory, biocompatibility and fatigue resistance. Nitinol parts.
What are the properties of nitinol?
Nitinol’s unique properties of shape memory and superelasticity result from a phase transformation within its crystal structure that happens with temperature change. At lower temperatures the structure is martensite, a weaker form, and at higher temperatures, austenite, which is stronger.
Why is nitinol superelastic?
This is due to martensite forming in areas that are stressed, even though the temperature is above where martensite normally occurs. Then, when the stress is removed this martensite returns to the undeformed austenitic state.
Why is Nitinol used for braces?
Because the wire is superelastic, it tries to return to its straight condition, and continually exerts a force on the teeth. This allows less frequent visits to the orthodontist to have braces tightened. A number of lesser-known applications use Nitinol’s shape memory capability.
What is the temperature above which the material remembers its high-temperature form?
The temperature above which the material remembers its high-temperature form is called the transformation temperature.
What is the name of the metal that is used to make shape memory?
A number of different shape memory materials have been developed, but one in particular has become a standby in many applications. Nitinol. The name comes from the metals it’s made of and the lab where this remarkable family of alloys was discovered. NiTi-NOL; Nickel, Titanium and Naval Ordnance Laboratory.
Can Nitinol be bent?
Though many Nitinol applications are invisible to the general public, some are quite familiar. Eyeglass frames made from Nitinol can be bent severely out of shape, but then return perfectly to normal. Also, some years ago, when cell phones had pull-out antennas, many of the antennas were made from Nitinol, allowing them to flex without breaking or permanently bending.
How does nitinol undergo phase transformation?
Nitinol undergoes the different phase transformations through changes in stress and changes in temperature. Understanding these phase changes, how and when they occur is just half the battle with manufacturing nitinol prototypes and devices.
What are the properties of nitinol?
We take advantage of two primary unique properties with Nitinol, especially with medical devices—shape memory and superelasticity.
What Characteristics of a Device Would Not Make It a Good Candidate for Using Nitinol?
Although nitinol has sufficient stiffness in most cases, applications where higher stiffness is required, we would recommend alternative materials such as stainless steel or titanium. Another characteristic of a medical device where Nitinol would not be a good fit is for anything that needs be magnetic.
What is nitinol used for?
Nitinol is used in a breadth of medical devices including orthopedic and respiratory applications . The most common medical devices that use Nitinol are typically found in cardiovascular, orthopedics, peripheral vascular and neurology—largely for the delivery options to make a procedure less invasive. Self-expanding stents are a good example of something we frequently manufacture.
Is nitinol the lowest cost material?
Additionally, Nitinol is not the lowest-cost material. For certain devices where cost is more of a factor, Nitinol might not be the right material. In addition, machining nitinol can be very challenging making it more expensive.
Can you expand a nitinol tube?
With Nitinol, we can start with a smaller tube, knowing we can expand it farther, and bend it more due to the higher tolerance for changes in strain when superelastic. Although the laser cut design greatly influences the expansion and bending capabilities, there’s a lot more range in the Nitinol than some other materials for the same laser-cut design.
