Microstructural evolution during isothermal aging at temperatures ranging from 673 K to 773 K was investigated by transmission electron microscopy (TEM) for Ni-rich Ti-Zr-Ni alloys. It was revealed that the aging is a two-stage process: the first stage is characterized by circular diffuse scattering in electron diffraction patterns, most likely attributed to short range ordered structure with no significant microstructural change. Second stage is characterized by a fine coherent precipitation followed by the coarsening. The precipitates had a lenticular shape and their habit was f100g B2 . The electron diffraction pattern of the sample containing the precipitates exhibited satellite spots at 1=3h110i B2 and 1=4h210i B2 positions. High resolution TEM observations and fast Fourier transformation analysis revealed that the h100i B2 electron diffraction pattern was composed of the reflection from 4 variants of the precipitates. The two-stage microstructural evolutions coincide well with the previously reported changes in mechanical properties and martensitic transformation behavior.
Effect of isothermal aging on martensitic transformation temperatures, mechanical
properties and microstructure was investigated for a Ni-rich Ti-Zr-Ni shape memory alloy at
temperatures ranging from 673 K to 773 K. The aging behaviour was two stage process: the first stage
associated with an increase in the Vickers hardness and a decrease in martensitic transformation
temperatures and the second stage with a decrease in the hardness and increase in the transformation
temperatures. Second stage was also characterized by the appearance of nano-scale precipitates,
which has never been reported.
tomy reveals the crystallographic information on the sectioned surface of the metallic block specimen. Philosophical Magazine, Taylor & Francis, 2010, 90 (29) Ultramicrotomy is widely regarded as a thin section preparation method for transmission electron microscopy (TEM) investigations. Here, we show that ultramicrotomy can also provide a simple path for microstructure analysis and assessment of mechanical properties for the sectioned blockface. Furthermore, electron backscatter diffraction (EBSD) analysis can be applied directly on ultramicrotomed surfaces without any additional polishing or etching. EBSD analysis relates the inherent cutting artifacts to the crystallographic orientations of the grains, hence delivering a rough assessment of their deformation resistance. TEM investigations revealed that crystallographicrelated cutting artifacts, which exhibit a wave-like pattern, are the result of the dislocation pile-ups close to the knife-specimen interface. We consider that this technique is suitable to be coupled with EBSD for three-dimensional microstructure reconstructions when used for serial sectioning of large volumes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.