development of pure titanium‐ based high‐strength wires€¦ · may 17‐19, 2017 •grand...
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Presenter’s Name, Presentation Title
May 17‐19, 2017 • Grand Hotel Krasnapolsky • Amsterdam, The Netherlands
Development of pure titanium‐based high‐strength wires
Possibilities for the medical industryJan Palán
Presenter’s Name, Presentation Title
May 17‐19, 2017 • Grand Hotel Krasnapolsky • Amsterdam, The Netherlands
Importance of the topic• Pure Titanium is considered the most biocompatible (corrosion from bodily
fluids, bio‐inertness, capacity for osseointegration, and high fatigue limit)• For some applications, the pure titanium has not got sufficient mechanical
properties• One way how to improve mechanical properties is an alloying, this could
negatively affect biocompatibilityAnother way how to increase the mechanical properties is to refine the structure to the level of nanometres using Severe Plastic Deformation
Presenter’s Name, Presentation Title
May 17‐19, 2017 • Grand Hotel Krasnapolsky • Amsterdam, The Netherlands
Company introduction
Presenter’s Name, Presentation Title
May 17‐19, 2017 • Grand Hotel Krasnapolsky • Amsterdam, The Netherlands
COMTES FHT a.s.
• COMTES FHT s.r.o. was established in December 2000• Company have been located in Dobřany, Czech Republic• Development of forming and heat treatment processes
Presenter’s Name, Presentation Title
May 17‐19, 2017 • Grand Hotel Krasnapolsky • Amsterdam, The Netherlands
Company structure and activities
• Comprehensive solution is provided by co‐operation between four departments
Mechanical testing
Materials analysis
Metallurgical technologies
Computer modelling
Presenter’s Name, Presentation Title
May 17‐19, 2017 • Grand Hotel Krasnapolsky • Amsterdam, The Netherlands
Metallurgical plant
Vacuum induction melting furnace up to 500 kg Universal hydraulic forging press for closed and open dies forging
Rolling mill for hot and cold rolling with options for thermo‐mechanical treatment
Layout
Presenter’s Name, Presentation Title
May 17‐19, 2017 • Grand Hotel Krasnapolsky • Amsterdam, The Netherlands
Bulk nanostructured materials from severe
plastic deformation (top down strategy)
Presenter’s Name, Presentation Title
May 17‐19, 2017 • Grand Hotel Krasnapolsky • Amsterdam, The Netherlands
Bulk nanostructured materials background
σy is the yield stress, σo is a materials constant,ky is the strengthening coefficient d is the average grain diameter
As the grain size decrease, the yield strength increase.As the amount of grain boundaries increase, the external load is then spread out among the larger interface, thus mechanical properties are increased.
Hall – Petch equation
Presenter’s Name, Presentation Title
May 17‐19, 2017 • Grand Hotel Krasnapolsky • Amsterdam, The Netherlands
Severe Plastic Deformation (SPD)• Way how to refine the structure to the level of nanometers, thus improve
mechanical properties• Grain refinement could be realized by SPD methods providing:Large deformation (logarithmic deformation = 7)Low temperatures in order to prevent softening processesHigh hydrostatic pressures• The well known method is equal channel angular pressing (ECAP). The
disadvantage is the low productivity of the method.
If these conditions are met, the method leads to formation of equiaxed refined grains
Presenter’s Name, Presentation Title
May 17‐19, 2017 • Grand Hotel Krasnapolsky • Amsterdam, The Netherlands
Development of the continuous production of nanostructured high
strength wires
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May 17‐19, 2017 • Grand Hotel Krasnapolsky • Amsterdam, The Netherlands
CONFORM technology• The CONFORM is usually used for continuous extrusion of
various profiles from non‐ferrous alloys • Various profiles are processed from a wire feedstock with
diameter from 5 to 13 mm. Another way is to use the powder or scrap as a feedstock (development scale).
Ni plate extrusion
Powder extrusion
Presenter’s Name, Presentation Title
May 17‐19, 2017 • Grand Hotel Krasnapolsky • Amsterdam, The Netherlands
CONFORM SPD technology
• COMTES FHT have been developing the technology CONFORM SPD• The technology combines the ECAP method with the CONFORM
technology and enables the cold extrusion of titaniumChamber die detail
CONFORM SPD principle
Presenter’s Name, Presentation Title
May 17‐19, 2017 • Grand Hotel Krasnapolsky • Amsterdam, The Netherlands
Microstructure evolution
• Ti Grade 2 (as‐received)• Typical microstructure with
annealing twins• Mean grain size 5390 nm
• 1 pass throughout the CONFORM SPD• Equiaxed grains with non‐homogenous
dislocation distribution• Mean grain size 320 nm
• 2 passes throughout the CONFORM SPD
• Mean grain size 250 nm
• 3 passes throughout the CONFORM SPD
• Mean grain size 330 nm
• Processing throughout the CONFORM SPD + Cold Working (CW)
• Mean grain size 220 nm
Deformation heat generation
Presenter’s Name, Presentation Title
May 17‐19, 2017 • Grand Hotel Krasnapolsky • Amsterdam, The Netherlands
Mechanical propertiesCondition
0.2 OYS UTS A5 RAMpa Mpa % %
as received 370 480 25 52CON SPD – 1 pass 644 675 20 62CON SPD – 2 passes 607 612 25 65CON SPD – 3 passes 600 607 28 63
CON SPD – 1 pass + CW (75%) 970 1072 10 52
CW only (75 %) 780 850 12 50
• Processing leads to more than twice higher mechanical properties
• CONFORM SPD process does not reduce the plasticity
• More than one pass leads to decrease of mechanical properties (post dynamic recrystallization)
• Subsequent cold working leads to further increase of mechanical properties
• Mechanical properties are related to the final diameter(cold reduction)
Condition0.2 OYS UTS A5 RAMPa MPa % %
as received 563 650 24 460CON SPD – 1 pass 759 791 26 64
CON SPD – 1 pass + CW (75%) 1115 1200 11 46
CON SPD – 1 pass + CW (88%) 1283 1320 9 50
CW only (75 %) 918 1003 7,8 40
Ti Grade 2
Ti Grade 4
Condition0.2 OYS UTS A5 RAMPa MPa % %
as received 880 950 15 45
Ti6Al4V (Ti Grade 5)
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May 17‐19, 2017 • Grand Hotel Krasnapolsky • Amsterdam, The Netherlands
Why nanostructured commercially pure titanium?
• The most common Ti alloy is Ti6Al4V is potencionaly dangerous for human body. V can cause potential citotoxicity and adverse tissue reactions (Steinemann, 1980), and Al ions from the alloy might cause long‐term Alzheimer diseases.
• The nanostructured cp titanium offers excellent biocompatibility combined with even higher strength then Ti6Al4V alloy.
• As mechanical properties are improved without changing the chemistry, so it is not necessary to verify its biocompatibility
• Improved mechanical properties allows to construct a smaller implants• The price of feedstock for making dental implants accounts for approx. 1–2%
of the implant price. This is a product with high added value, where the use of nanostructured titanium delivers improved properties, and therefore increases the price. The effect of the higher material prices on manufacturing costs will be minimal.
Presenter’s Name, Presentation Title
May 17‐19, 2017 • Grand Hotel Krasnapolsky • Amsterdam, The Netherlands
Thank you for your attention