ASTM F2516 | Metals | Tension Testing
Nitinol is a metal alloy composed of titanium and nickel. Nitinol is characterized by its biocompatibility, superelasticity, fatigue strength, and ability to return to its original shape after deformation (shape memory). Although nitinol is used in industries ranging from robotics to clothing, it is in the medical field where the material really shines. Medical applications of nitinol include: vascular stents, eyeglasses, orthodontics, prosthetics, surgical applications, and much more.
ASTM F2516 Standard Test Method for Tension Testing of Nickel-Titanium Superelastic Materials provides information on the strength, ductility and superelasticity under uniaxial tensile loading.
Prior to conducting ASTM F2516, it is important to read the entire specification in the relevant ASTM publication.
ASTM F2516 | Metals | Tension Testing
- Before moving forward with the test, please read and arrange your testing setup in accordance with ASTM E8 – Standard Tension Testing of Metallic Materials.
- Tests are to be conducted at room temperature.
- Secure the specimen in fixtures, making sure there is no pre-applied load. ASTM E8 recommends wedge grips like the ones pictured herein for testing thin wire (a common form of nitinol in medical applications).
- For wire diameters greater than 0.2mm, an extensometer is required to measure strain. For diameters less than or equal to 0.2mm, crosshead displacement may be used for strain measurements.
- The test is conducted by pulling the sample to 6% strain then unloading to less than 7 MPa, then pulling to failure. Crosshead speed differs between the first and second loading cycle and is dependent on wire diameter. Refer to Table 1 in ASTM F2516 for the appropriate crosshead rates.
- Upper Plateau Strength
- Lower Plateau Strength
- Residual Elongation
- Elongation
ASTM F2516 | Metals | Tension Testing
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- ADMET offers a full line of grips for ASTM F2516
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- Simulated MTESTQuattro Test Report for ASTM F2516
ASTM F2516 | Metals | Tension Testing
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