NiTi Properties

. AVAILABILITY:
Conventional Nitinol is available as
- Nitinol classic - Unitek corporation.
- Titanal - Lancer pacific.
- Orthonol - Rocky mountain
orthodontics.
www.indiandentalacademy.com

PSEUDOELASTIC NITINOL:
In the late 1980s, new Nickel titanium wires with an
Active Austenitic grain structure appeared.
These wires exhibited the remarkable property of
NiTi alloys – SUPERELASTICITY.
1. SUPERELASTICITY: Manifested by very large
reversible strains and a nonelastic stress strain or force
deflection curve.

This group is also referred to as A-NiTi.
This group includes :
- Chinese NiTi.
- Japanese NiTi (Sentinol)
- 27°C superelastic Cu-NiTi.
In Austenitic active alloy both Martensite and
Austenitic phases play an important role during
its mechanical deformation

MECHANISM OF SUPERELASTICITY:
Stress Induced Martensitic Transformation : (SIM)
Unique force deflection curve for A-NiTi occurs because of phase
transition in grain structure from Austenite to Martensite, in
response not to temperature change but applied force.
This transformation is mechanical analogue of thermally induced
shape memory effect. ,the Austenitic alloy undergoes a transition
in internal structure in response to stress without requiring a
significant temperature change.

It is possible for these materials as their TTR is
close to room temperature.
Md
: It is the highest temperature at which
martensite formation can be induced by stress.
Md
of A-NiTi group is above mouth temperature
allowing formation of SIM at oral temperature.

• Af
(Austenitic finish) of these alloys is below mouth
temperature.
⇓
• Formation of SIM is reversible when stress is
reduced.
• These alloys cannot be easily cooled down below
their Ms.
⇓
Do not display clinically useful shape memory.

• To exploit superelasticity to its fullest potential the
working temperature of orthodontic appliances should
be greater than the Af
temperature.
• It is the differential between Af
temperature and mouth
temperature that determines the force generated by NiTi
alloys.
Af
can be controlled over wide range by affecting
composition, thermomechanical treatment and
manufacturing process of alloy

 . A superelastic material will not be superelastic at all
temperatures, but will exhibit good superelastic
properties in a temperature window extending from
the Active Af temperature upto a temperature which
is about 50°C above active Af.
 a material with an Active Af of about 15°C will exhibit
good superelasticity upto about 65°C which means
that the material will exhibit good superelasticity at
both room temperature and body temperature

CHINESE NiTi
Developed by Dr. Tien Hua Cheng and associates for
orthodontic applications at the General Research
Institute for Non ferrous metals in Beijing, China.
Reported by Burstone in 1985.
Spring Back :
At 80° of activation.
Chinese NiTi wire has :
- 1.4 times the springback of Nitinol wire.
- 4.6 times the springback of SS wire.

Activation (original 80°) and reactivation (to 40°) curves for
NiTi wire. The moment decreases to 383 gm-mm after 40° of
deactivation. If the wire is untied and retied into a bracket
(reactivation), the moment increases to 700 gm-mm.

 - stiffness of Chinese NiTi is 36% that of Nitinol wire.
 - temperature dependent effects are clinically insignificant.
 Chinese NiTi deformation is not particularly time dependent unlike
nitinol wire, will not continue to deform a significant amount in mouth
between adjustments.
The initial activation force required for austenitic NiTi can be 3
times greater than the force required to deflect a classic work
hardened martensitic wire (Nitinol).
once the SIM is formed, the horizontal plateau appears and the
alloy ‘absorbs’ any additional load stress and releases it in
constant amounts during the deactivation phase.

JAPANESE NiTi
In 1978 : Furukawa Electric Co. Ltd. of Japan produced a
new type of Japanese NiTi alloy.
In 1986 : Miura et al reported on Japanese NiTi
Superelasticity is produced by stress, not by temperature
change and is called stress induced Martensitic
transformation (SIM).
Provides light continuous force for physiologic tooth
movement

 The relationship between the temperature and
time of the heat treatment of the Japanese NiTi
alloy wire was studied to optimize the super-
elastic properties of the alloy. When the heat
application was raised to 500° C, the force level
indicating the super-elastic property could be
reduced.
 arch wires providing a different magnitude of
force can be fabricated from the wires of the
same diameter. In addition, in the preformed arch
wire, different magnitudes of force can be
produced by controlling the temperature and time
in the desired section of the arch wire.

Japanese NiTi is marketed as Sentalloy.

 Other SE niti wires
3M Unitek:Nitinol Super Elastic
American Orthodontics:Titanium Memory
Wire:Available in two force levels : Force I – low
force,Force II – high force.
Ortho Organizers:Nitanium
Masel Orthodontics Elastinol

 ADVANTAGES:
 1. Constant force over wide range of deflection.
2. Low stiffness.
3. High springback.
4. More effective in initial tooth alignment.
5. Less patient discomfort.
LIMITATIONS OF SUPERELASTIC NiTi:
1. Cannot be soldered or welded.
2. Poor formability.
3. Tendency for dentoalveolar expansion.
4. “Travels” around the arch.
5. Expensive.

Thermoelastic nitinol
Thermal analog of pseudoelasticity in which
martensitic phase transformation occurs from
Austenite as temperature is decreased. This
phase transformation can be reversed by
increasing the temperature to its original value.

CHARACTERISTICS OF AN IDEAL THERMODYNAMIC NITINOL
WIRE:
1.    Dead soft at room temperature so that it can be tied easily.
2.    Instantaneously activated by heat of mouth.
3.    Able to apply clinically acceptable orthodontic forces.
4.    Once fully activated would not be affected further by increased
heat in the mouth.
5.    A fairly narrow TTR i.e., it should be completely active at mouth
temperature yet completely passive at lower temperature. This
property would allow the clinician sufficient time to tie archwire
into the bracket slots before heat of mouth activates the wire.


 Thermoelastic Nitinol – formable at ice water temperatures.
⇓
 Ice water is below Ms of thermoelastic wires
⇓
 Martensite while engaging
 When warmed above Af
by mouth temp.
⇓
 Transformation is reversed to from Austenite
⇓
 Wire returns to its original shape thus displaying shape memory.

 Active Martensite Thermodynamic Wire:Included in the active
martensitic group are wires with an Af set at a temperature at or
above 37°C [CuNiTi 37°C and CuNiTi 40°C], which is almost
complete, transformed into martensite during clinical application.
 Martensitic alloy has a greater working range than austenite,
and it may therefore prove advantageous during the process of
alignment and leveling. The ability to vary transition
temperatures in martensitic wires of identical dimensions, allows
the clinician to apply appropriate levels of physiological force
during alignment, whilst maintaining archwire size.
‘Neosentalloy’ archwire marketed by GAC*, which has three
force levels for single arch dimensions.

This wire combines greater heat sensitivity, high
shape memory, and extremely low, constant
forces to provide a full-size wire that can be
inserted early in treatment

 Bioforce Sentalloy – A Graded Thermodynamic Wire The heat
treatment of selected sections of the archwire by
means of different electric current delivered by
electric pliers modified the values of the deactivation
forces by varying the amount of austenite present in
the alloy.After heating the anterior segment for 60
minutes, the linear plateau of the deactivation force
dropped to 80 g in a 3-point bending test at room
temperature. Similar manufacturing procedures have
been perfected to produce wires such as Bioforce
Sentalloy (GAC) that are able to deliver selective
forces according to the needs of the individual dental
arch segments

 BioForce (GAC) offers 80 grams of
force for anteriors and up to 320 grams
for molars

COPPER NiTi
Invented by Dr. Rohit Sachdeva – 1994.
COMPOSITION : Quaternary alloy containing.
* Nickel * Copper (5 – 6%)
* Titanium * Chromium (0.2 – 0.5%)
Copper:
-      Increases strength
-      Reduces hysteresis
-    these benefits occur at expense of increasing TTR above that of
oral cavity.
Chromium : to compensate for the above mentioned unwanted
effect 0.5% chromium is added to return TTR close to oral
temperature

TYPES OF CU-NITI:
1. Type I Af 15°C.
2. Type II Af 27°C
3. Type III Af 35°C
4. Type IV Af 40°C

 These 4 alloys form the basis for “Variable Transformation Temperature
Orthodontic
1. Type I – Af - 15°C
Not frequently used
Generates very heavy forces.
2. Type II – Af - 27°C
Generates highest forces of 3 types (II, III and IV)
Indications:
• In patients who have an average or higher pain threshold.
In patients who have normal periodontal health.
In patients where rapid tooth movement is required and force system generated
by archwire is constant


3. Type III Af 35°C
Generates forces in mid range.
Indications:
• Patients who have a low to normal pain threshold.
In patients whose periodontium is normal to slightly compromised.
Where relatively low forces are desired.
4. Type IV Af - 40°C
• These wires generate forces only when mouth temperature
exceeds 40°C.
Intermittent forces.

Indications:
• Patients who are sensitive to pain.
Patients who have compromised PDL conditions.
Where tooth movement is deliberately slowed down i.e when the
patient may not be able to visit the orthodontist regularly or poor
patient cooperation

ADVANTAGES OF Cu-NiTi OVER OTHER NiTi Alloys:
1.    Cu – NiTi generates more constant force over long activation
spans.
2.    More resistant to permanent deformation.
3.    Exhibits better springback properties.
4.    Exhibits smaller drop in unloading forces (reduced hysteresis).
Provides precise TTRs at 4 different levels – Enables Clinician to
select archwires on a case specific

Reflex wire (TP Orthodontics) -Af set at 27ºC,
2 superelastic copper NiTi wires (Copper Ni-Ti; Ormco) have Af
set at 27ºC and 35ºC
Heat Activated NiTi alloy (Highland Metals) has an Af set at 68ºC
and an Mf set at 24ºC; this alloy has a considerably extended
TTR, and the phase transition is present consistently during
clinical applications.
40ºC Thermo-Active Copper Ni-Ti (Ormco) can be considered truly
superelastic at oral temperature.
The Af of Sentalloy (GAC) is approximately 22ºC in the absence
of loading.and for neosentalloy 28 ºC
Other manufacturers generally claim an Af set at a nominal oral
temperature, approximately 35ºC.59

Clinical Choice of a Ni-Ti Alloy
ALIGNMENT:
Principles of choice for alignment arches:
1.    Arch wires for alignment should provide light, continuous force
of approx. 50 gms.
2.    Arch wires should be able to move freely within the brackets.
3.    Rectangular arch wires which fit tight within bracket slots so that
position of root apices could be affected – should be avoided.
4.     Springier the alignment arch wire, the more important is that
crowding be atleast reasonably symmetric. The flat load
deflection curve of superelastic NiTi makes it ideal for initial
alignment when degree of crowding is similar on two sides of
arch.

2. FINISHING:
In Finishing Stage:
Appropriate stiffness at relatively small deflections
rather than range is primary consideration.
If rectangular A-NiTi is used in finishing stage –
Torsional stiffness must be considered in choice of wire.
M-NiTi usually is better choice (21 x 25 M-NiTi for 0.022
slot) for rectangular NiTi wires

 True thermoelastic alloys may therefore be indicated
for early torque control during the alignment phase of
treatment and in periodontally compromised patients.

RECENT ADVANCES IN NICKEL TITANIUM
ARCH WIRES:
1. DUAL FLEX ARCHWIRES
Invented by James L Cannon.
Consists of anterior and posterior segments of different
stiffnesses.
a. Dual flex Archwire # 1
-      Anterior segment – 0.016 Titanal (Nickel titanium)
-      Posterior segment – 0.016 Stainless steel.
Advantages:
•     Anterior segment flexible – simplifies. Bracket in engagement in
crowded anterior teeth.
•      Posterior segment rigid – controls rotation, prevents tipping
from elastic traction and permits bite opening bends to be made
easily.

. Dual Flex Archwire # 2:
Anterior segment – 0.016 x 0.022 Titanal.
Posterior segment – 0.018 stainless steel

2. SPEED SUPERCABLE ARCHWIRES:
Speed system – developed by H.G. Hanson.
SPEED: An acronym of words : Spring loaded, Precision,
Edgewise, Energy and delivery
Two Types of Archwires are used in Speed System:
- “Speed” super cable.
- “Speed” D archwires.
a. Speed Super Cable Archwires:
Superelastic NiTi coaxial wire – 7 stranded.

b. Speed “D” archwires:
Unique half round square wires.
Suited for full 3-D control while sliding.
The unique D wire profile cooperates with the speed spring
clip to ensure highest degree of precision and control
during sliding mechanics.
AVAILABILITY:
Supplied by OREC corporation

3. NITROGEN COATED ARCHWIRES:
Appearance of Titanium alloys is not esthetic ,several methods of
surface hardening as well as several coatings have been
developed.
Implanting Nitrogen on surface of NiTi alloys by Ion implantation
process – NITRIDING.
Advantages:
-       Make Titanium more esthetically pleasing giving it gold like
aspect.
-      Hardens surface.
-      Reduces friction.
-      Reduces Nickel release into mouth.
e.g : Bioforce Ionguard - 3µm Nitrogen coating.

The IONGUARD process actually alters the
wire’s surface to provide a dramatically
reduced coefficient of friction for sliding
mechanics that are better than the same size
stainless steel wire and half the friction of
competitive NiTi wire. It also seals the
occlusal surface of the wire to eliminate
breakage and reduce nickel leaching. While
the IONGUARD process alters the surface of
the wire, none of the wire’s unique properties
is changed.

Recycling & Sterilization of Nickel Titanium
Archwires
The combined effects of repeated clinical use
and sterilization may subject the wire to
corrosion and cold working with a resultant
alteration in its properties Mayhew and Kusy
and Buckthal and Kusy have demonstrated
no appreciable loss in properties of nitinol
wires after as many as three cycles of various
forms of heat sterilization or chemical
disinfection,

. For effective sterilization, steam autoclaving (ideally
at 134ºC, 32 psi for 3 minutes) is the method
recommended. For instruments unable to withstand
autoclaving, an effective cold disinfection solution
such as 2% glutaraldehyde is an alternative.
investigation on the effects of a simulated oral
environment on 0.016” nickel titanium wires, Harris et
al noted a significant decrease in yield strength of
these wires over a period of four months.

nickel titanium wires, especially those of the
pseudoelastic type, undergo phase changes
as a result of heat treatment that substantially
alters their properties. Burstone et al and
Miura et al noted that temperatures greater
than 60ºC increased the susceptibility of
these austenitic nickel titanium wires to
plastic deformation and decreased their
springback.

BETA TITANIUM ARCH WIRES

In 1980 – Burstone and Goldberg developed Beta titanium alloy
for orthodontic use.
For orthodontic use Dr. Burstone’s Primary Objectives were to
develop an alloy which :
-      Has a good springback
-      Stiffness lower than SS wires which would allow wires to fill the
bracket for control and at same time produces lighter forces.
-      High formability.
Sold as TMA wire (Titanium Molybdenum Alloy) – By Ormco
Corporation.

COMPOSITION :
Titanium – 79%
Molybdenum – 11%
Zirconium – 6%
Tin – 4%

. METALLURGICAL ASPECTS :
Pure Titanium
At temp. below 885°C – HCP lattice or α-phase is stable
At higher temperature – BCC lattice or β-phase is stable
Addition of elements such as Molybdenum / Columbium
⇓
Stabilize β-phase at room temp
⇓
Beta Stabilized alloys

IV. PROPERTIES :
1. Stiffness:
β-Ti – Its MOE is less than ½ that of SS and approximately
twice that of Nitinol.
Clinical Relevance: This makes it use ideal in situations
in which forces less than that of SS are necessary and
in instances in which a lower modulus material such as
Nitinol is inadequate to produce the desired force
magnitudes.

2. Spring Back :
-      Superior to that of SS wire.
-       β-Ti can be deflected twice as much as SS wire without permanent
deformation.
-      Delivers half the amount of force as compared to SS wire.
Advantage: Of full bracket engagement and a resultant greater torque control
than smaller SS wire.
3. Formability:
-      Good formability
-      Allows loops and stops to be bent
-      Wires shouldn’t be bent over sharp radius.

4. Corrosion Resistance :
Comparable to SS and Co-Cr alloys.
5. Friction:
• Demonstrate highest levels of friction.
 Although NiTi has a greater surface roughness, Beta titanium has
greater frictional resistance.
 As titanium content of alloy increases its surface reactivity
increases and surface chemistry is a major influence on frictional
behaviour.
Beta titanium – 80% titanium
⇓

Wire “Cold Welds” itself to steel bracket, making sliding all but
impossible.
Possible Solution: Ion implantation – alteration of surface of
titanium wires by implantation of ions into the surface.
6. Joinability:
Allows direct welding of auxiliaries without reinforcement by
soldering.
- It is the only orthodontic wire alloy that possesses true
weldability

7. Heat Treatment:
- Heat treatment – not recommended for TMA wire.
Beta titanium alloy does respond to precipitation hardening
procedure.

Procedure:
Solution heat treatment between approximately 700°C and 730°C
followed by quenching. Then aging at approximately 450°C
Results in peak value for YS/E ratio

Wire Alloy Composition (wt%) Modulus
of
Elasticity
(GPa)
Yield
Strength
(MPa)a
Springbackb
Austenitic
stainless
steel
17-20% Cr. 8-12%
Ni. 0.15% C (max),
balance mainly Fe
160-180 1100-
1500
0.0060-0.0094
(AR) 0.0065-
0.0099 (HT)
Cobalt-
chromium-
nickel
(Elgiloy
Blue)
40% Co. 20%Cr.
15% Ni. 15.8% Fe,
7% Mo, 2% Mn,
0.15% C, 0.04%
Be
160-190 830-
1.000
0.0045-0.0065
(AR) 0.0054-
0.0074 (HT)
Beta-
titanium
(TMA)
77.8% Ti, 11.3%
Mo, 6.6 %Zr, 4.3%
Sn
62-69 690-970 0.0094-0.011
Nickel-
titanium
55% Ni, 45%Ti
(approx. and may
contain small
amounts of Cu or
other elements)
34 210-410 0.0058-0.016

PRINCIPLES OF TMA WELDING
a. Proper positioning
b. Minimum voltage
c. Small contact area
d. Single short pulse
e. Pressure.
Any welder that can variably control voltage can be used.
a. Positioning:
- Wires are constantly held in contact throughout the heating
process.
-

Broad flat electrodes are used rather than pointed electrodes –
assures that parts are properly held together before welding
process during heating.
- Application of current through two wires
⇓
Melting process occurs
⇓
 Actual merging in which one wire has “SET DOWN” about 80%
into second wire.
 25 – 60% “set down” is recommended for most applications.
b. Voltage :
Most important variable under control of orthodontist.
Low Voltage : Welded parts will not stick together

Correct Voltage : Weld will eventually occur and it is not possible to
delaminate the weld joint by twisting.
Greater Voltage :
Increased heat may lead to increased wire brittleness.
Springback properties wouldn’t be affected.
c. Contact Area:
• Greater contact area – greater voltage is required.
Smaller contact areas are desirable – higher localized heats are
produced giving an excellent weld without influencing remainder
of wire.
A ‘T’ joint is preferable for most orthodontic applications because it
has smallest contact area.

d. Pulse:
Basic weld can be accomplished with only one pulse.
Pulse should be of very short duration.
Additional pulses are rarely successful in producing the
desired weld as “Set Down” which occurs after initial
pulse produces large contact between two wires and
therefore heat is dissipated so that insufficient heat is
available to the parts

A good clinical weld is characterized by
(1) little discoloration,
(2) little weld flash
(3) a set down (the amount the welded wire merges into
the main wire) not greater than 25%.

CLINICAL APPLICATIONS :
Ideal edgewise arches fabricated of β-titanium have
significant superiority over stainless steel. They can be
deflected twice as far without permanent deformation
which allows greater range of action for either initial
tooth alignment or finishing arches.
For eg: 0.018 x 0.025 inch wire in Beta titanium delivers
about same force as an 0.014 x 0.020 inch SS wire.
Therefore advantage of full bracket engagement and
third order or torque control if used in 0.018 inch slot
bracket.

1. Use of β - Ti as Finishing Arches :
-       Steel finishing wires are too stiff in both 18 and 22 slot
appliances.
-      In 18 slot → 17 x 25 Beta – Ti.
-      For full expression of torque in 22 slot. Best finishing wire is
21x25 Beta – Ti torsional stiffness is less than that of SS.
1.       Beta Titanium can be formed into arches or segments with
complicated loop configurations
Eg: “T”, vertical, helical and “L” loops

. Specialized spring or auxiliaries can be fabricated from TMA wire.
e.g : Intrusion arch
Canine root spring
Torquing auxiliary
Intrusion Arch: Can be fabricated from 17 x 25 TMA or 16 x 22
TMA

. ADVANTAGES :
• Intermediate force delivery between SS or Elgiloy and Nickel
titanium.
Excellent formability.
Only orthodontic wire with true weldability.
Excellent spring back properties.
Excellent biocompatibility – High Ti Content.
DISADVANTAGE:
Expensive
High arch-wire bracket friction with original TMA.

AVAILABILITY:
1. Ormco Corporation:
- TMA arch wires.
Straight lengths (14”) and preformed arches
- Reverse Curve TMA :
Rectangular – 0.016 x 0.022, 0.017 x 0.025, 0.019 x 0.025

- Reverse Curve with “T” Loops :
Rectangular – 0.016 x 0.022, 0.017 x 0.025, 0.019 x 0.025

2. Dentaurum
Rematitan Special
Straight lengths
3. Unitek Corporation :
Unitek Beta III Titanium Archwire
Preformed arches.
4.Leone
BETA MEMORIA

ION IMPLANTATION OF TMA:
Ion implantation is a process by which various elements or compounds are
ionized and then accelerated toward a target and is deposited on the surface.
Procedure :
•     Takes place in vacuum chamber.
•     Vapor flux of ions is generated with an electron beam evaporator and
deposited on surface.
•     Nitrogen and oxygen ions are obtained from plasma and accelerated at
energies of several hundred to several thousands of volts.
⇓
Ions penetrate surface of wire on impact
⇓
React to produce TiO and TiN
⇓
Renders surface hard and smooth ↓ friction.

Advantages of Ion Implantation :
Produces no sharp interface between coating and wire which can
lead to bond failure or delamination.
Doesn’t alter wire dimension.
Depth, distribution and conc. profile can be controlled by varying ion
dosage and energy.
It can take place at low temperature. Hence doesn’t degrade basic
properties of archwire

 Effects on Friction (Burstone et al 1995)
Static Kinetic
•Untreated TMA
0.52 0.51
•SS
0.19 0.18
•Treated TMA
0.13 0.10 – 0.22

Other Findings:
1. No significant difference in tensile strength, MOE.
2. Ductility increased marginally.
Resistance to fracture and fatigue is increased.
Availability:
1. Ormco Corporation:Low Friction TMA :Preformed arches
2. . Colored TMA :
Preformed arches
Various colors Aqua
Violet
Purple
Honey dew

ALFA TITANIUM ARCHWIRES

These wires were developed by
A.J. Wilcock Jr. in 1988.
. COMPOSITION :
* Titanium - 88.9%
* Aluminium - 7.86%
* Vanadium - 4.05%

•      Hexagonal close packed lattice (HCP) in contrast to BCC
lattice of TMA.
•      Hexagonal lattice possesses fewer slip planes – less ductile
than β - Ti.
•     Alloy is strictly near alpha phase titanium alloy rather than pure
α-titanium alloy because there is certain amount of Beta phase
retained in at room temperature.
•      Manufactured by a technique called “Feed Centreless
Grinding”
•     Stabilizing elements – Aluminium and Vanadium.

• Wires are soft enough for initial gentle action on teeth inspite of
large wire dimension.
Wire is relatively soft while shaping and easier to bend.
Hardens and become brittle with passage of time in the mouth.
⇓
Due to absorption of hydrogen atoms
⇓
Formation of Titanium hydrides
Can be welded

The elastic modulus and yield strength at room
temperature for α-titanium is approximately 110 GPa
and 40 MPa respectively
CLINICAL APPLICATIONS:
Rectangular wires of sizes of 0.022 x 0.018 (Ribbon mode) or
0.20 x 0.020 (Square) are used as finishing wires in Begg
technique.
Alpha titanium combination wire with an Ant. Ribbon (0.022 x
0.018) and post. Round (0.018) sections – Excellent breaking
mechanism in second stage of Begg.

AVAILABILITY:
A.J. Wilcock
Alpha titanium wires.
Rectangular
Square
Combination

Titanium-Niobium Archwire
Made from Nickel free Titanium Niobium alloy
PROPERTIES :
According to manufacturers product information
TiNb is
- Soft and easy to form.
- Same working range as SS
Stiffness is 20% lower than TMA and 70% lower
than SS.

Dalstra et al (2000) :
Assessed mechanical properties of TiNb and compared them
with SS.
- Stiffness of TiNb in bending is roughly ½ that of SS whereas in
torsion it is roughly 1/3. These characteristics enable clinician to
use TiNb for creative bends without excessive force levels of
steel wires.
- Spring back:
In bending – 14% lower than that of SS
In torsion – same or even slightly higher than SS.
Weldability of TiNb wires was found to be good.

The average stiffness of Titanium Niobium was 8.6%
higher than TMA at 1266g/mm, although Titanium
Niobium is advertised as being 80%the stiffness of
TMA.32

AVAILABILITY :
Ormco Corporation :
Titanium Niobium / FA

NiTi Properties

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