ADVANCED MATERIALS & PROCESSES | MARCH 2025 38 8 After extensive discussions, the task group concluded that F2063 should remain exclusive to binary Nitinol, given its predominant use in medical applications. Currently complex alloys and PVD products lack dedicated specifications. While referencing F2063 for these materials is a common practice, it is technically inaccurate. The proposed solution is to develop distinct standards for these specialized materials while keeping F2063 streamlined for binary Nitinol medical industry users. Another major focus is defining material grades based on micro-cleanliness. The existing metrics—maximum inclusion size and area fraction—are overly simplistic. More robust methods, such as inclusion density and extreme value analysis for predicting maximum inclusion dimensions, may provide better classification criteria. Since micro-cleanliness evolves through thermo-mechanical processing and directly affects medical components under varying design and stress conditions, further research is needed. Establishing a strong predictive correlation between new metrics and cyclic fatigue life is essential before integrating them into ASTM standards for semi-finished Nitinol products (wire, tube, sheet, etc.). WK 61694 Specification for Wrought Nickel-Titanium Wire for SMA Medical Devices and Surgical Implants. No standard specification defining requirements for nickel- titanium shape memory alloy wire for use in medical devices and surgical implants exists. This standard specification will be used by medical device companies, metal wire producers and government agencies to ensure consistent product and assist with quality control. This specification covers the requirements for wrought nickel-titanium shape memory alloy wire, nominally 54.5 to 57.0 mass/mass (weight) % nickel, used for the manufacture of medical devices and surgical implants. Material shall conform to the applicable requirements of Specification F2063. This specification addresses those product variables that differentiate drawn medical grade wire from the raw material and mill product forms covered in Specification F2063. WK 84718 Specification for Wrought Nickel-Titanium SMA Sheet and Foil for Medical Devices and Surgical Implants. There is no standard specification to address the requirements specifically for nickel-titanium shape memory alloy flat rolled plate, sheet, and foil. This proposed new standard specification will be used by medical device companies, metal producers, and government agencies to ensure consistent product and assist with quality control. This specification covers the requirements for wrought nickel-titanium shape memory alloy flat rolled products including plate, sheet, and foil, nominally 54.5 to 57.0 mass/ mass (weight) % nickel, used for the manufacture of medical devices and surgical implants. Material shall conform to the applicable requirements of Specification F2063. This specification addresses those product variables that differentiate flat rolled plate, sheet and foil from the raw material and mill product forms covered in Specification F2063. WK 82516 Wrought NiTi-based SMA for Actuation. While there exists a broad range of potential applications for SMA actuators, their transition to production is hindered by a lack of standardized material specifications. To address this need, a new specification that evaluates and controls the wrought NiTi-based material for actuation is being developed under ASTM work item WK 82516. The draft specification considers several grades of material including ternary alloys and high-transition temperature Ti-rich material. More generally, a grading system has been established to categorize alloys by transition temperature and micro-cleanliness, two key considerations when selecting material for use in actuation applications. While wrought material itself is not suitable for direct use in actuation applications, follow-on specifications covering processed and finished forms are anticipated. It is recognized that, due to chemical composition overlap between the new specification and the specifi- cation for Wrought NiTi SMAs for Medical Devices and Surgical Implants (F2063), there is potential for confusion within industry. While the main differentiator can be found within the specifications’ respective scope statements, it is helpful to recognize the fundamental differences in practical application. Use cases in the medical industry TABLE 1 − RESOURCES FOR MORE INFORMATION ON SMA STANDARDS DEVELOPMENT ASTM work items (WK) and activities Contact Contact email WK 84104 Dr. Matthias Frotscher matthias.frotscher@biotronik.com WK 90888 Dr. Weimin Yin wyin@resonetics.com WK 61694, WK 84718 Dr. Maximilien E. Launey maximilien.launey@g-rau.com WK 82516 Dean Pick dean.pick@kiniticsautomation.com WK 74640 Dr. Doug Nicholson douglas.e.nicholson@boeing.com Elastocaloric standards Prof. Dr.-Ing. Paul Motzki paul.motzki@zema.de FEATURE
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