|About this Abstract
||Materials Science & Technology 2019
||Advanced Manufacturing, Processing, Characterization and Modeling of Functional Materials
||Effects of High Temperature Oxides on the Thermomechanical Properties of NiTiHf20 Shape Memory Alloy Wires
||Avery W. Young, Robert W Wheeler, Nathan A Ley, Othmane Benafan, Marcus L Young
|On-Site Speaker (Planned)
||Avery W. Young
High temperature shape memory alloys (HTSMAs) show potential for improving aircraft fuel-efficiency and reducing the mass of payloads launched into orbit and beyond. The superior work output demonstrated by NiTiHf HTSMAs has established this alloy system as a prime candidate for HTSMA actuators in aerospace applications.
In this presentation the processability of NiTiHf wires is addressed. Hot-extruded Ni50.7Ti29.4Hf19.9 rods with an initial diameter of 6.35 mm, were hot-rolled at 725, 750, 775, and 800°C, respectively, to a final diameter of ≈ 1.9 mm, across 32 non-consecutive hot passes. To investigate the influence of high temperature oxides (formed during hot-rolling) on mechanical properties, thermomechanical testing, verified with digital image correlation (DIC) strain mapping, was performed on oxidized & cleaned Ni50.7Ti29.4Hf19.9 HTSMA wires. This comparative study provides insight into the failure mechanisms associated with high temperature Ni(Ti,Hf) oxides, and demonstrates how wire ductility and overall functionality can be improved through oxide removal.