ADVANCED MATERIALS & PROCESSES | MARCH 2025 36 6 FEATURE DO SHAPE MEMORY ALLOYS HAVE STANDARDS? A growing collection of standard material specs and test methods has been established to assess and control quality in shape memory alloys for medical devices and actuator applications. Douglas E. Nicholson, The Boeing Company, Saint Louis Othmane Benafan, FASM* and Glen S. Bigelow, NASA Glenn Research Center, Cleveland Dean Pick,* Kinitics Automation, Vancouver, Canada Luca Fumagalli, SAES Getters, Lainate, Italy Weimin Yin,* Resonetics Smart Materials, New Hartford, New York Matthias Frotscher,* Cortronik GmbH, Rostock-Warnemuende, Germany Maximilien E. Launey,* G. Rau Inc., Scotts Valley, California Paul Motzki,* ZeMA gGmbH, Saarbrücken, Germany In the early 1990s the use of superelastic shape memory alloy (SMA) for medical devices was on the verge of a multi-billion-dollar industry with no standard specifications and test methods available[1]. This motivated the development of the first set of standard terminology, specifications and test methods for NiTi based SMA[2,3]. Here, the SMA community focused on characterizing and optimizing processes for a single binary NiTi alloy system with 54.5 to 57.0 wt% nickel and niche applications[2]. In the early 2000s the first set of ASTM were published, which included F2004[4], F2005[5], F2063[6], and F208[7] for binary NiTi for medical device material and test methods. At the time, it was already well known that composition, processing, metallurgical structure, and heat treatment had a significant influence on the thermal and mechanical properties and fatigue life of SMAs in the end-product[8,9]. With this in consideration, F2063 was created to specify requirements and test methods for verifying chemical composition, transformation temperatures, metallurgical structure (including grain-size, porosity, and nonmetallic inclusions), and mechanical properties of wrought binary NiTi. Non-SMA specific test methods are described in F2063 for analyzing chemical composition[10], grain-size[11], nonmetallic inclusions[12], and mechanical properties[13]. ASTM test methods *Member of ASM International Fig. 1 — Ecosystem of ASTM shape memory alloy standards for medical devices and actuation.
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