Download NiTi shape memory alloys (Nitinol)

Shape Memory Alloys for
Biomedical Aplications
Ni-Ti alloys
β-Ti alloys
Prof. dr. ir. Jan Van Humbeeck
Dep. MTM-KU Leuven
SHAPE MEMORY ALLOYS
Ed. Hiroyazu Funakubo,
Gordon and Breach, 1987 by OPA
ISBN 2-88124-136-0
ENGINEERING ASPECTS OF SHAPE MEMORY ALLOYS
Ed. T.W. Duerig, K.N. Melton, D. Stôckel, C.M. Wayman,
ISBN 0-750-61009-3
Buttherworth-Heinemann Ltd, 1990
THE APPLICATION OF SHAPE MEMORYALLOYS IN
MEDICINE
J.P. Lipscomb and L.D. Nokes,
Ed. Anthony Row ltd, 1996
ISBN 0852989563
SHAPE MEMORY MATERIALS
K.Ostsuka and C.M. Wayman
Cambridge University Press, 1999
ISBN 052144487X
DELAY LAW AND NEW CLASS OF MATERIALS AND
IMPLANTS IN MEDICINE
Ed by E. Gunther,
Northampton , MA 2000, STT2000
ISBN 9702353-0-5 (printed in Russia)
SHAPE MEMORY IMPLANTS
Ed. L. Yahia,
Springer 2000
ISBN 3-540-67229-X
Books on Shape Memory Alloys
SHAPE MEMORY ALLOYS:MODELING AND ENGINEERING
APPLICATIONS
Ed. C. Lagoudas
Springer 2008
THIN FILM SHAPE MEMORY ALLOYS
FUNDAMENTALS AND DEVICE APPLICATIONS
Ed. S. Miyazaki, Yong Qing Fu and Wei Min Huang
Cambridge University Press 2009
ISBN 978-0-521-88576-8
SHAPE MEMORY ALLOYS FOR BIOMEDICAL APPLICATIONS
Ed. T. Yoneyama and S. Miyazaki,
Woodhead Publ., CRC, 2009
ISBN 978-1-84569-344-2
SHAPE MEMORY ALLOYS
Ed. C. Cismasiu
Published by Siyo (Croatia), 2010
ISBN 978-953-307-106-0
SHAPE MEMORY AND SUPERELASTIC ALLOYS/ TECHNOLOGIES AND
APPLICATIONS
Ed. By K. Yamauchi, I. Ohkata, K. Tsuchiya, S. Miyazaki,
Woodhead publ. Cie, 2011
ISBN 978-1-84569-705-5
SHAPE MEMORY MICROACTUATORS
M. Kohl,
Springer 2004
ISBN 3-540-20635-3
SHAPE MEMORY ALLOYS-PROCESSING? CHARCTERISATION AND
APPLICATIONS
Ed. By F.M. Braz Fernandez
Publ. by In Tech (Croatia), March 2013
ISBN 978-953-51-1084-2
PHYSICAL METALLURGY OF NiTi BASED SHAPE
MEMORY ALLOYS
K. Otsuka and X. Ren
Progress in materials Science 50(200() pp. 511-678
SHAPE MEMORY ALLOYS HANDBOOK
Christan Lexcellent
ISBN: 978-1-84821-434-7
Wiley-ISTE, March 2013
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Important properties of Biomaterials
• Biocompatibilty
– Ion-exchange,
– Toxicity,
– Corrosion (passivation)
• Surface properties:
– Roughness
– Surface energy
• Mechanocompatibility
– E-modulus
– Fatigue
– Wear
• Manufacturability (machinability)
Requirements for Medical Implants
(biomaterials)
• The reliability of the mechanical functions and
functional properties
• The chemical reliability (the resistance to
deterioration of their properties in a biological
medium, the resistance to expansion, dissolution,
corrosion)
• Biological reliability-biological compatibility, lack of
toxicity and carcenogenicity, resistance to the
formation of thrombus and antigens.
NiTi alloys
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NiTi shape memory alloys
(Nitinol)
• Ni50Ti50 is an intermetallic compound which exhibits a
thermoelastic martensitic transformation around room
temperature
• The hot phase is called beta, the cold phase is called
martensite.
• This transformation is characterized by its transformation
temperatures.
• The martensitic variants can reorient through deformation of
the martensite or induced in the beta phase under loading.
• This special deformation mode forms the basis of the
functional properties: shape memory effect, pseudo-elasticity
and damping.
• NiTi-shape memory alloys are very biocompatible :
- intermetallic compound (strong bounds between Ni and Ti)
- passivation by Ti02 –surface layer
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Influence of the composition on the transformation temperatures (TT):
400°C and 500°C give the TT after cold deformation and
recovery annealing at those temperatures
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NiTi-alloys
The transformation temperatures of those alloys
are controlled by
•
•
•
•
Composition
Impurities
Degree of cold deformation
Recovery annealing temperature (controls
precipitates and defects concentrations and distributions)
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Alloying of NiTi
• To decrease the hysteresis (Cu) or to increase
(Nb)
• To decrease the TT (Fe, Cr, Co, Al), i.e.
Ni39,8Ti49,8Cu10Cr0,4
• To increase the TT (Hf, Zr, Pd, Pt, Au)
• To increase the strength of the matrix (Mo, W,
O, C)
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Properties of NiTi SMA
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Biocompatibility of NiTi
• NiTi is bio-inert (osteopermissive)
– intermetallic compound
– Ti02 passivation
• Deviation of stoechiometry (more or less than 2% Ni)
decreases slightly the corrosion resistance
• Alloying with elements of the Pt-group (Ru, Rh, Os,
Ir, Pd, Pt) or Mo improves the corrosion resistance.
TiNi-Mo has a better passivation.
• Alloying with Cu, Fe, Mn, Al decreases the corrosion
resistance
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Table 3
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Corrosion resistance
13
Influence of sterilisation techniques on Ni-release
14
Difference due to variable Ni surface concentrations reported on NiTi wires (0.4-15at%)
High-temperature treatments, which promote the formation of a thicker external
Ti-oxide layer, result in Ni accumulation in the internal surface layers.
S. Shabalovskaya and J. Van Humbeeck, “Biocompatibility for biomedical applications”,
Chapter 9, SHAPE MEMORY ALLOYS FOR BIOMEDICAL APPLICATIONS
Ed. T. Yoneyama and S. Miyazaki,Woodhead Publ., CRC, 2009, ISBN 978-1-84569-344-2
a:TEM image of a cross section of the microwire.
b: Schematic of the average Ni and Ti contents at different spot locations in
the wire as determined by EDXS.
H. Tian,1 D. Schryvers, S. Shabalovskaya, and J. Van Humbeeck
“Microstructure of Surface and Subsurface Layers of a Ni-Ti Shape Memory Microwire”
Microsc. Microanal. 15, 62–70, 2009
Beta-Ti alloys
• Ti melts at 1668°C and exhibits during further cooling an allotropic solid
state transformation from the bcc (β) to the hcp (α) phase at 882,5°C.
• Depending on the alloying elements, one defines α, α+β or β alloys related
to the microstructure at room temperature.
• The most important alloys used as biomaterials are Cp-Titanium (α -alloy)
(commercial pure) (ASTM F67), Ti-6Al-4V (α+β ) (ASTM F136) and TMA (β)
(ASTM 1713).
• Ti-alloys are sensitive to hydrogen brittleness.
• Ti-alloys are passivated by a TiO2 ( 10 nm) surface layer which forms
spontaneously in air.
• Ti-alloys have a very high pitting corrosion potential and are few sensitive
to galvanic and stress corrosion.
• Titanium is also interesting due to its low density (4.51 ton/m3) and low Emodulus (order of 100 GPa) and very good fatigue properties.
• Titanium and its alloys exhibit a poor wear resistance.
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Beta-Ti alloys
• β (bcc)-stabilizing elements to be added. α(hcp)/α+β
border decreases with increasing concentration of
the alloying element.
• Quenching of β leads to martensite formation (α’ or
α”.
• α”-martensite (orthorombic) is required. α’martensite (hexagonal) does not show SME.
• α”-martensite is favoured by higher alloying content
and higher quenching rate.
• ω phase has to be avoided.
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19
Ti-alloys
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Compositions and electron/atom ratios
of the α’/ α” boundary
in some Ti-TM binary alloys
“The Physical Metallurgy of Titanium Alloys”, E.W. Collings, ASME ISBN 0-87170-181-2, 1984
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How to obtain α’’-martensite
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Biocompatibility of beta-Ti alloys?
• E. Eisenbarth et al., “Biocompatibility of betastabilizing elements of Titanium alloys”,
Biomaterials 25 (2004) 5705-5713
– Decreasing biocompatibility: Nb-Ta-Ti-Zr-Al-316LMo
– Al: potentially necrotic
– Mo: cytotoxic effects, moderate toxic,
– Nb, Ta, Ti, Zr: inertness
Compositions of beta-Ti alloys for
biomedical applications
• Ti-(10-12)Mo-(2,8-4)Al-(0-2)Cr-(0-2)V-(0-4)Nb
US Patent 6,258,182 BI, July 10, 2001
• Ti-10V-2Fe-3Al-0.2N
• Ti-(20-30)Nb-(2-15)Zr-(2-12)Sn-(0-2)Al
• Ti-30nb-(8-10)Ta-5Zr
• Ti-(8-10)Mo-(2.8-6)Al-2V-4Nb
• ………….
Summary and a future direction
Ti-Nb superelastic alloy
+ Zr: increases transformation strain but accelerate the formation of w phase.
+ Sn(Al) : suppresses formation of w phase and increases transformation strain.
+ O, N: create nano-domains and increase critical stress for slip deformation.
Ti-Nb-Zr-(Sn, Al)-(O,N) alloys
Further improvement by thermomechanical treatment and texture control.
More than 6% of superelastic recovery.
Stress (MPa)
600
Ti-Nb-Zr-Sn
400
200
0
0
1
2
3
4
5
6
7
8
9
10
11
12
Strain (%)
Slide obtained from prof. S. Miyazaki
Biomedical Applications
•
•
•
•
•
•
•
•
Orthodontic devices
Guidewires
Non-invasive surgical instruments
Orthopaedic implants
Stents
Filters
Exo-prosthesis
…
Securing the Human Body
28
Applications of SMA as biomaterials
29
Orthodontic
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Compare the stored energy of a
stainless steel wire and a
pseudoelastic NiTi.
Moreover during the tooth movement
the stress in NiTi will remain constant
for along time while for SS the stress
decreases fast.
The frequency of correction is thus
lower for NiTi alloys
.
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Orthodontic wires
32
Medical instruments
A 1-mm-diam urological grasper (Bacher, Tuttlingen, Germany)
demonstrates kink resistance.
The shaft comprises a nitinol wire concentrically
placed in a nitinol tube;
the distal end is a hinged, stainless-steel grasper,
which opens to an approximately 90° included angle.
A Simon filter,
shown in longitudinal and transverse views of the deployed state
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Guidewires:
-high flexibility and high kink resistance
Superelastic NiTi endodontic files for root canal surgery
•Steerable biliary guidewire (Director)
34
Stents
• Self expanding stents on the basis of the
pseudo-elastic property.
• Balloon-expandable stents
• Expansion on the basis of the shape memory
effect
• “Drug delivery” stents
• (Removable stents as long the stent is not
encapsulated.)
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Stents produced by laser cutting of a tube
Self expandable (Angiomed)
Wire-stent
36
Mounting a stent trough
balloon dilatation
A self expanding stent pushed out
of the catheter
37
NDC
“Stents”
Amplatzer
39
Bone grafts
Fracture recovery by applying
special NiTi grafts
After the
operation
After one
month
41
Biorthex porous NiTi for bone reconstruction
42
Porous structures by “3D-printing”
Biomedical
porosity
Generating
Test
Samples
3D
printing
Evaluating
Performance
43
From design to biomedical application
 NiTi; Porous Acetabular Cup; Cellular Gyroid
Generating
Porous
Architecture
Biomedical
component
44
Market prospects: 14,24% growth 2013-2018
• Global Shape Memory Alloy Market 20142018
– Published: July 2014
– 58 pages
– Price: 1953 EURO
• Global Shape Memory Material Market
Research Report
– Publish Date: 28 Sep 2014
– Next Update Date: 28 Dec 2014
– Price: 3425 EURO
You do not have to ask questions,
but if you feel a need for it please do so.
Thank you
https://www.uantwerpen.be/en/conferences/esomat-2015/newsletter/
Keynote speakers:
Ryosuke Kainuma (TU, Japan) “martensitic transformations at low T in high Ni-content alloys”
Francesca Caballero (CENIM, Spain) “martensite and bainite in nanostructured steels”
Hanus Seiner (CTU, Czech Rep.) “mobile interfacial microstructures in SMAs”
Elisabeth Gautier (CNRS, France) “diffusionless transformations in Ti alloys“:
Yinong Liu (UWA, Australia) “new directions for SMAs in composite systems”
Richard James (UMN, USA) “future directions in martensitic and multi-ferroic systems”