Recently, NiTiHf-based HTSMAs have been shown to exhibit unique precipitation and mechanical behavior. In this study, a rolled plate of NiTiHf HTSMA was homogenized and heat treated at various times and temperatures and characterized using a barrage of analytical techniques including high-energy synchrotron X-ray diffraction (SR-XRD). Neither homogenization nor any of heat treatments studied significantly affect the austenitic or martensitic transformation temperatures. H-phase was observed to precipitate at heat treating times below 30 minutes and then to subsequently dissolve away for times of 30 minutes and above. The presence of H-phase dramatically increases the material strength by almost a factor of 2, Lastly, an over-aging effect occurs with increasing time due to the disappearance of the H-phase.

Volume Subject Area:
Development and Characterization of Multifunctional Materials
Topics:
Heat, Temperature, Barrages, Martensitic transformations, Mechanical behavior, Precipitation, Strength (Materials), X-ray diffraction
This content is only available via PDF.
Copyright © 2015 by ASME
You do not currently have access to this content.