Transcript Titanium Alloy

Titanium Alloy
Titanium and its alloys have proven to be
technically superior and cost-effective materials of
construction for a wide variety of aerospace,
industrial, marine and medical applications.
In North America, approximately 70% of the
titanium consumed is utilized for aerospace
applications.
Due to the expansion of existing applications and
the development of new uses, the greatest growth
will occur in the industrial, marine and commercial
sectors.
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Titanium Alloy
Titanium is a white metal, and has the best
strength to weight ratio among the metals.
Titanium is very reactive, and because of this
it is often used for alloying and deoxidizing
other metals.
Titanium is a more powerful deoxidizer of
steel than silicon or manganese.
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Titanium Alloy
Titanium is 40% lighter than steel and 60% heavier
than aluminum.
This combination of high strength and low weight
makes titanium a very useful structural metal.
Titanium also features excellent corrosion
resistance, which stems from a thin oxide surface
film which protects it from atmospheric and ocean
conditions as well as a wide variety of chemicals.
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Titanium Alloy Grade
There are five grades of what is known as
commercially pure or unalloyed titanium,
ASTM Grades 1 through 4, and 7.
Each grade has a different amount of
impurity content, with Grade 1 being the
most pure.
Tensile strengths vary from 172 MPa for
Grade 1 to 483 MPa for Grade 4.
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Titanium Alpha Alloy
Titanium alpha alloys are alloys that typically
contain aluminum and tin, though they can also
contain molybdenum, zirconium, nitrogen,
vanadium, columbium, tantalum, and silicon.
Alpha alloys do not generally respond to heat
treatment, but they are weldable and are commonly
used for cryogenic applications, airplane parts, and
chemical processing equipment.
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Titanium Alpha-Beta Alloy
Alpha-beta alloys can be strengthened by heat
treatment and aging, and therefore can undergo
manufacturing while the material is still ductile, then
undergo heat treatment to strengthen the material,
which is a big advantage.
The alloys are used in aircraft and aircraft turbine
parts, chemical processing equipment, marine
hardware, and prosthetic devices.
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Titanium Alpha-Beta Alloy
The smallest group of titanium alloys, beta alloys
have good hardenability, good cold formability
when they are solution-treated, and high strength
when they are aged.
Beta alloys are slightly more dense than other
titanium alloys, having densities ranging from 4840
to 5060 kg/m3.
They are the least creep resistant alloys, they are
weldable, and can have yield strengths up to 1345
MPa.
They are used for heavier duty purposes on
aircraft.
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Titanium Alloy Implants
Market:
Titanium is a standard material for medical devices
such as hip joints, bone screws, knee joints, bone
plates, dental implants, surgical devices,
pacemaker cases and centrifuges due to its total
resistance to attack by body fluids, high strength
and low modulus.
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Titanium Alloy Implants
Metal of choice:
The body readily accepts titanium since it is
more biocompatible than stainless steel or
cobalt chrome. Titanium also has a higher
fatigue strength than many other metals. The
unique qualities of titanium prove to be MRI
(Magnetic Resonance Imaging ) and CT
(Computed Tomography ) compatible.
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Titanium Alloy Implants
Machinability:
The machinability of titanium is comparable to most
stainless steels and better than cobalt chrome.
Sharp, clean tools with good chip removal and
ample coolant are recommended when Drilling,
Turning, Milling or Cold Sawing titanium. The work
hardening rate for titanium is less than stainless
steel.
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Titanium Alloy Implants
Medical Specifications for Titanium Alloy:
ASTM F-67-68(94)E1
Unalloyed titanium for surgical implant applications.
ASTM F-136-92E1
Wrought titanium 6Al-4V ELi Alloy for surgical implant
applications
ASTM F 1472-93
Wrought titanium 6Al-4V Alloy for surgical implant applications.
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Titanium in Medical Applications
Bone and Joint Replacement:
About one million patients worldwide are treated
annually for total replacement of arthritic hips and
knee joints.
The prostheses come in many shapes and sizes.
Hip joints normally have a metallic femoral stem
and head which locates into an ultrahigh molecular
weight low friction polyethylene socket, both
secured in position with polymethyl methacrylate
bone cement.
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Titanium in Medical Applications
Bone and Joint Replacement:
Some designs, including cementless joints, use
roughened bioactive surfaces (including
hydroxyapatite) to stimulate osseointegration, limit
resorption and thus increase the implant lifetime for
younger recipients.
Internal and external bone-fracture fixation provides
a further major application for titanium as spinal
fusion devices, pins, bone-plates, screws,
intramedullary nails, and external fixators.
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Titanium in Medical Applications
Dental Implants:
A major change in restorative dental practice
worldwide has been possible through the use of
titanium implants.
A titanium 'root' is introduced into the jaw bone with
time subsequently allowed for osseointegration.
The superstructure of the tooth is then built onto the
implant to give an effective replacement.
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Titanium in Medical Applications
Cardiovascular devices:
Titanium is regularly used for pacemaker
cases and defibrillators, as the carrier
structure for replacement heart valves, and
for intra-vascular stents.
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Titanium in Medical Applications
External Prostheses:
Titanium is suitable for both temporary and
long term external fixations and devices as
well as for orthotic calipers and artificial
limbs, both of which use titanium extensively
for its light weight, toughness and corrosion
resistance.
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Titanium in Medical Applications
Surgical Instruments:
A wide range of surgical instruments are made in
titanium.
The metal's lightness is a positive aid to reducing
any fatigue of the surgeon.
Instruments are frequently anodised to provide a
non reflecting surface, essential in microsurgical
operations, for example in eye surgery.
Titanium instruments withstand repeat sterilisation
without compromise to edge or surface quality,
corrosion resistance or strength.
Titanium is non magnetic, and there is therefore no
threat of damage to small and sensitive implanted
electronic devices.
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