ASTM F2516-14 Tensile Testing Nitinol Wire
Nitinol is a shape memory, super-elastic alloy that is used extensively in the biomedical industry. For example, Nitinol is used in stents, dental wires, catheter guidewires, internal fracture fixation devices, and biopsy forceps. ASTM F2516-14 requires an extensometer of Class C or better to be used for wires with a diameter greater than 0.2 mm. The test method is designed to pull the material in tension to 6% strain, then unload the material to a value of less than 7MPa, before being pulled to failure.
The challenges of testing Nitinol wire to this standard are:
- Accurate strain measurement
- The weight of a clip-on extensometer may cause bending of the wire, and the knife-edges may slip, damage the wire, or lead to premature failure
- Secure gripping for varying specimen diameters
- Accurate turnaround points
- For wire with a diameter greater than 0.2 mm, we recommend using the Advanced Video Extensometer (AVE 2) or Automatic Contacting Extensometer (AutoX). Both the AVE 2 and AutoX are capable of measuring strain in cyclic loading and to failure without damaging the Nitinol wire.
- For thinner diameter wire, we recommend using pneumatic cord and yarn grips. For thicker diameter wire, we recommend using 5kN pneumatic side action grips with serrated faces.
- The 5900 controller and Bluehill® Universal software with the TestProfiler module allow for easy programming and real-time calculation of loading and unloading turnaround points. Instron provides a pre-configured test method for testing to ASTM F2516-14 in the Biomedical Applications Module.
5900 Universal Testing Systems are engineered for precision, built for durability, and offer the flexibility for changing requirements. They are designed with standard and optional features that increase testing efficiency and improve the testing experience for the operator. A wide range of models are available for testing capacities from < 100N up to 600kN.
- 6.8 MB
Instron 3300 Series Universal Testing Systems for Tensile, Compression, Bend, and other material property tests.
- 2.2 MB
Bluehill Universal Software is built from the ground-up for touch interaction and an intuitive user experience. Discover simpler and smarter testing with features such as pre-loaded test methods, QuickTest in seconds, enhanced data exporting: and Instron Connect – a new feature that provides a direct communication link to Service. Users of previous versions of software such as Bluehill 2 and Bluehill 3 can easily upgrade to the newest version of Bluehill.
- 2.6 MB
Pneumatic cord and yarn grips provide a convenient method for clamping fiber, cord, yarns and fine wires to reduce the problem associated with testing these materials. A specially designed horn with a smooth finish and a contoured surface with a graduated cam allows for easy loading and a stress reduced clamping area on the specimen. The clamping mechanism can be activated either automatically or through a foot switch. This allows hands-free grip operation enabling the specimen to be held with both hands, for easy loading. Pneumatic cord and yarn grips provide selectable clamping force to accommodate different materials and excellent follow-up action which compensates for decay of the holding force due to specimen creep.
- 0.8 MB
Instron® 2712-04x Series Pneumatic grips, packed with features to enhance gripping performance, usability, and operator safety.
- 1.1 MB
The second generation Advanced Video Extensometer (AVE 2) utilizes patented measurement technology in the fastest, most accurate non-contacting strain measurement device commercially available.
- 1.3 MB
The AutoX 750 is a high-resolution, long-travel automatic contacting extensometer. It can be mounted onto any electromechanical 3300, 5500, or 5900 table top and floor model systems, as well as LX, DX, HDX, and KN static hydraulic testing systems. It is well suited for applications involving plastics, metals, biomedical, composites, elastomers, and more. The AutoX has a maximum travel of 750 mm and accuracy of ± 1 µm.
- 1.4 MB