Transcript Slide 1
Hierarchical Manufacturing and Modeling
for Phase Transforming Active Nanostructures
D.C. Lagoudas a, K. Gall b, I. Karaman c, X. Zhang c, J. Kameoka d
a
Department of Aerospace Engineering, Texas A&M University, College Station, Texas 77843-3141; b School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0250;
c Department of Mechanical Engineering, Texas A&M University, College Station, Texas 77843-3123; d Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843-3128
Fabrication and Properties of MSMA
Thin Films
Overall Concept
Sputtering System
Fabrication of Monolithic and Hybrid
SMA and MSMA Nanowire
Nanowire Fabrication Procedure
Magnetron sputtering system for
multilayer film depositions. The
system has four magnetron guns
capable of DC and RF sputtering
and is able to obtain a base
pressure of 10-8 Torr or better. A
load lock is attached to the system
to increase the throughput of the
system.
Electrospinning of Silica Nanofiber Membrane
Mechanical
Arm
•Solution: a mixture of spin on glass coating (SOG),
polyvinylpyrrolidone (PVP), and butanol.
Pressing
Chamber
Hydraulic
Jack
•Solution concentration: PVP 0.04 g/ml, SOG:butanol = 4:1 in
volume ratio.
Mold containing
template and
thin film
Anodized Aluminum Oxide
(AAO) Template (Empty)
•Understand the effect of nanoscale manufacturing on reversible
martensitic phase transformations
•Develop low-cost and easily scalable nanomanufacturing
techniques that will allow fabrication of shape memory alloy
(SMA) and magnetic shape memory (MSMA) alloy nanowires
•Processing parameters: feeding rate: 8 ul/min, applied voltage: 7
kV, deposition distance: 5 cm, heating temperature: 500°C for 12h.
•PVP was removed during the heating. Resultant silica membrane
was composed of nanofiber with ~100 nm in diameter.
NiMnGa Thin Films
Project Objectives
Fabrication of Nanofiber Membrane
for Protein Detection
Performance of Protein Detection
NiMnGa Thin Films were deposited on
several substrates. Mn-rich target with the
composition of Ni49.5Mn30Ga20.5 was used.
The composition was tailored by varying the
deposition power.
Filled AAO template
after extrusion
•Random-distributed electrospun nanofibers formed a porous
membrane. The membrane is incorporated in the layered structure
of the detector.
In-21at%Tl Nanowires in
Cross-Section of AAO
Indium-Thallium (In-21at%Tl) Nanowires
Various diameters of In-21at%Tl nanowires fabricated (750nm, 380nm,
280nm, 70nm, 33nm). For nanowires of diameters >70nm, twins
observed at room temperature along entire length of nanowires
•Fabricate higher scale structures and devices from nanowires and
hybrid thin films
•The sensitivity is improved due to the small diameter of nanofibers
and the resultant extremely large surface area to volume ratio.
•Use multiscale modeling framework to guide the fabrication
process, reveal fundamental multi-scale physical phenomena in
reversible phase transformation, and aide design of higher scale
devices
•Fabrication of nanofiber membrane for protein detection
The as-deposited films
were partly crystalline
as seen in the xrd pattern
The DSC plot shows reversible martensite
to austenite phase transformation
Multiscale Modeling Framework and
Simulation
TEM Dark field image of 70nm
diameter nanowire showing BCT twins
at room temperature
TEM dark field image of 200nm
diameter nanowire showing BCT twins
at room temperature
SEM image of silica spun
nanofibers
Modeling In-21at%Tl bulk
and nanowires
2
3
Developing new potentials based on ab initio
calculations
RT
1
Above Af
Nanoscale Martensitic Transformation
Mechanisms in NiTi
TEM Dark field image of 70nm
diameter nanowire with constant crystal
structure at 100°C
Multilayer twinned B19’
TEM Dark field image of 33nm
diameter nanowire at room
temperature
Below Mf
•The detection limit is 32
times lower than traditional
96-well enzyme-linked
immunosorbent assay
(ELISA).
•The detection time is 1h
compared to ELISA’s 1 day
As-deposited film shows grains with needle shaped texture indicating
martensite, distributed in a seemingly amorphous matrix. Above Af, the
diffraction pattern shows a significant change in SADP along with grain
growth. Change in SADP was again observed when cooled below Mf
3 Layers
Schematic of nanofiber
membrane protein detector
1
2
3
2 Layers
NiMnCoIn Thin Films
Compared with shuffling to B19
two layers of atoms
out of four layers
one layer of atoms out of two layers
_
0
100
200
300
400
500
[011] B 2
1/2[100] {011}
Shuffling
[100] B 2
•DSC curves of crystallization
process in freestanding
Ni50Co6Mn38In6 films heated linearly
at different rates. The effective
crystallization energy was
calculated to be 86.59 kJ mol-1.
• Graduate a diverse group of students prepared for research on
nanotechnology with an interdisciplinary and global outlook
Future Work
• Motivate undergraduates, particularly those from
underrepresented groups, to continue to graduate school and
research careers
80 °C/min
40 °C/min
• Fabricate In-21at%Tl nanowires of smaller diameter
20 °C/min
10 °C/min
5 °C/min
• Fabricate NiMnCoIn nanowires from produced thin films
300
400
Temperature (°C)
500
Educational Goals
• For 70nm diameter nanowires, reversible phase transformation
observed from BCT martensite to FCC austenite
• For 33nm diameter nanowires, SAED patterns indicate FCC crystal
structure (austenite) at room temperature
Temperature (°C)
Shuffling
[011]B 2
418.25 °C
shuffling
1/8[100] {011}
[011]B 2
450.45 °C
Exothermic
011 (011) B 2
•DSC curve of an as deposited,
amorphous freestanding
Ni50Co6Mn38In6 film. The film
was heated/cooled/heated at a
rate of 80 °C/min.
Exothermic
• Surface energy will reduce as twin width increases
• Agree well with the experimental observation
Selected Area Electron Diffraction (SAED) patterns of 33nm diameter
nanowire at room temperature
341.26 °C
• Educate undergraduate and K-12 students and teachers on
technology, its benefits, and to communicate the excitement of
discovery of science