Ideal-Learning
Nitinol and the Shape Memory Effect - December
Nitinol (NiTi) is a shape memory alloy made of nickel and titanium in almost equal concentrations. Some of its major applications are in medical devices where its unique properties allow minimally invasive surgery and implants to improve quality of life for millions of people.
Conventional materials like stainless steels exhibit different elastic deformation behaviour than structural biological materials in the human body. Elastic deformation of such materials is limited to about 1% and strain is proportional to applied load.
Hair, tendon and bone can be elastically deformed up to 10% strain in a non-linear way. Superelastic (austenitic) Nitinol stress-strain behaviour has been shown to be very similar to that of structures in the human body.
Stents implanted in the peripheral arteries are exposed to high mechanical stress from the surrounding environment, for example bending of the knee, walking or running. Nitinol is able to handle these external forces better than other materials due to its characteristic properties of superelasticity and stress hysteresis.
Why is Nitinol used in medical devices?
A shape memory alloy has the ability to restore its original shape after deformation. In medical devices, Nitinol is popular due to its biocompatibility, superelasticity and fatigue and kink resistance. Nitinol is used to manufacture catheter tubes, guidewires, stone retrieval baskets, filters, needles, dental files and archwires and other surgical instruments.The Shape Memory Effect
The most common demonstration of the shape memory effect is that a piece of the alloy can be deformed and then the deformation can be completely removed by heating the metal a small amount, as by dipping it into hot water.Conventional materials like stainless steels exhibit different elastic deformation behaviour than structural biological materials in the human body. Elastic deformation of such materials is limited to about 1% and strain is proportional to applied load.
Hair, tendon and bone can be elastically deformed up to 10% strain in a non-linear way. Superelastic (austenitic) Nitinol stress-strain behaviour has been shown to be very similar to that of structures in the human body.
Stents implanted in the peripheral arteries are exposed to high mechanical stress from the surrounding environment, for example bending of the knee, walking or running. Nitinol is able to handle these external forces better than other materials due to its characteristic properties of superelasticity and stress hysteresis.
Why Ideal-tek?
Ergo-tek Tungsten Carbide Cutters are specially designed for cutting hard metals and tough wires (Piano Wire, Diode Leads, Nickel, Stainless Steel, Nitinol). They can be used on single or multiple filars and for lateral or internal cuts. Made of high quality ball bearing steel, they feature Tungsten carbide inserts that allow to cut hard wires preventing blade damaging. Typical applications include cutting stents, braided mesh, catheters and guide wires in medical device manufacturing.
