Peter Anderson Ph.D. Ohio State University "Fundamentals and Applications of Ambient and High-Temperature Shape Memory Alloys"

101 Thomas Building 3:05 pm to 4:20 pm

Shape memory alloys (SMAs) offer the potential for a vast array of applications, including actuators for reconfigurable blades on rotorcrafts, variable geometry chevrons on aircraft engines, flap actuators on aircraft wings, and even shape-changing bio-inspired structures. However, there are considerable materials challenges that include functional and structural fatigue under repeated actuation. Understanding these phenomena is critical to the design and application of new high temperature SMAs for automotive and turbine engine applications.

This talk focuses on the underlying deformation phenomena in SMAs at the micro- and nano- structural scale. Transmission electron microscopy studies show that plasticity develops when SMAs are heated and cooled, even in the absence of an external load! This is captured in recent phase-field simulations that predict plastic deformation at the transformation front—a phenomena that alters the martensitic structure and performance of the SMA. New high-temperature Ni-Ti-Hf alloys employ nanoscale precipitates that suppress plasticity yet allow the phase transformation progress seamlessly. Corresponding simulations suggest why the precipitates are so effective. This work is supported by the Department of Energy/Basic Energy Sciences.