Hierarchical Manufacturing and Modeling

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 AM
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 AM University, College
Station, Texas 77843-3123 d Department of
Electrical and Computer Engineering, Texas AM
University, College Station, Texas 77843-3128
Sputtering System
Nanowire Fabrication Procedure
Electrospinning of Silica Nanofiber Membrane

• Solution a mixture of spin on glass coating
  (SOG), polyvinylpyrrolidone (PVP), and butanol.
• Solution concentration PVP 0.04 g/ml,
  SOGbutanol 41 in volume ratio.
• Processing parameters feeding rate 8 ul/min,
  applied voltage 7 kV, deposition distance 5 cm,
  heating temperature 500C for 12h.
• PVP was removed during the heating. Resultant
  silica membrane was composed of nanofiber with
  100 nm in diameter.

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.
Anodized Aluminum Oxide (AAO) Template (Empty)
NiMnGa Thin Films
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.

• 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
• Fabricate higher scale structures and devices
  from nanowires and hybrid thin films
• 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

• Random-distributed electrospun nanofibers formed
  a porous membrane. The membrane is incorporated
  in the layered structure of the detector.
• The sensitivity is improved due to the small
  diameter of nanofibers and the resultant
  extremely large surface area to volume ratio.

Filled AAO template after extrusion
In-21atTl Nanowires in Cross-Section of AAO
The as-deposited films were partly crystalline
as seen in the xrd pattern
The DSC plot shows reversible martensite to
austenite phase transformation  
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
Schematic of nanofiber membrane protein detector
Modeling In-21atTl bulk and nanowires Developing
new potentials based on ab initio calculations
RT
Above Af

• The detection limit is 32 times lower than
  traditional 96-well enzyme-linked immunosorbent
  assay (ELISA).
• The detection time is 1h compared to ELISAs 1 day

Nanoscale Martensitic Transformation Mechanisms
in NiTi
TEM Dark field image of 33nm diameter nanowire at
room temperature
TEM Dark field image of 70nm diameter nanowire
with constant crystal structure at 100C
Multilayer twinned B19
Below Mf
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
Selected Area Electron Diffraction (SAED)
patterns of 33nm diameter nanowire at room
temperature
NiMnCoIn Thin Films

• Surface energy will reduce as twin width
  increases
• Agree well with the experimental observation

• DSC curve of an as deposited,
• amorphous freestanding
• Ni50Co6Mn38In6 film. The film
• was heated/cooled/heated at a
• rate of 80 C/min.

• 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

• Graduate a diverse group of students prepared
  for research on
• nanotechnology with an interdisciplinary and
  global outlook
• Motivate undergraduates, particularly those from
  
• underrepresented groups, to continue to
  graduate school and
• research careers
• Educate undergraduate and K-12 students and
  teachers on
• technology, its benefits, and to communicate
  the excitement of
• discovery of science

Compared with shuffling to B19
two layers of atoms out of four layers
one layer of atoms out of two layers
shuffling

• 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.