The use of nanostructures has become very common throughout high-tech industries.
In order to enhance the applicability of Shape Memory Alloys (SMAs) in
systems such as Nano-Electromechanical Systems, the phase transformation behavior
of SMA nanostructures should be explored. The primary focus of this work is on the
fabrication of metallic nanowires and the characterization of the phase transformation
of SMA nanowires. Various metallic nanowires are fabricated through the use of the
mechanical pressure injection method. The mechanical pressure injection method is a
template assisted nanowire fabrication method in which an anodized aluminum oxide
(AAO) template is impregnated with liquid metal. The fabrication procedure of the
AAO templates is analyzed in order to determine the effect of the various fabrication
steps. Furthermore, metallic nanowires are embedded into polymeric nano bers as a
means to incorporate nanowires within other nanostructures.
The knowledge obtained through the analysis of the AAO template fabrication
guides the fabrication of SMA nanowires of various diameters. The fabrication of
SMA nanowires with di fferent diameters is accomplished through the fabrication of
AAO templates of varying diameters. The phase transformation behavior of the fabricated
SMA nanowires is characterized through transmission electron microscopy.
By analyzing the fabricated SMA nanowires, it is found that none of the fabricated
SMA nanowires exhibit a size eff ect on the phase transformation. The lack of a
size e ffect on the phase transition of SMA nanowires is contrary to the results for
SMA nanograins, nanocrystals, and thin films, which all exhibit a size eff ect on the phase transformation. The lack of a size eff ect is further studied through molecular
dynamic simulations. These simulations show that free-standing metallic nanowires
will exhibit a phase transformation when their diameters are sufficiently small. Furthermore,
the application of a constraint on metallic nanowires will inhibit the phase
transformation shown for unconstrained metallic nanowires. Therefore, it is concluded
that free-standing SMA nanowires will exhibit a phase transformation throughout the
nanoscale, but constrained SMA nanowires will reach a critical size below which the
phase transformation is inhibited.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2010-08-8355 |
| Date | 2010 August 1900 |
| Creators | Phillips, Francis Randall |
| Contributors | Lagoudas, Dimitris C. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | thesis, text |
| Format | application/pdf |
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