This paper describes manufacture of nano-structural titanium, its structure and properties. Nano-titanium has higher specific strength properties than ordinary (coarse-grained) titanium. Nano-titanium was produced by the equal-channel angular pressing (ETAP) process. The research it self was focused on physical base of strengthening and softening processes and developments occurring at the grain boundaries during the ECAP process at half-hot temperature. Strength of nano-titanium varies around 960 MPa, grain size around 300 nm.Rad opisuje proizvodnju nanostrukturnog titana te njegovu strukturu i svojstva. Nanotitan se odlikuje višom čvrstoćom od običnog, krupnozrnatog, i proizveden je kanalno kutnim prešanjem (KKP). Samo istraživanje bilo je usmjereno na fizikalne osnove procesa očvršćavanja i omekšavanja na granicama zrna tijekom procesa kanalno kutnim prešanjem (KKP) na srednjim temperaturama. Čvrstoća nanotitana varira oko 960 MPa, a veličina zrna je oko 300 nm

J. Kliber

L. Kander

M. Greger

M. Černý

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M. GREGER, M. ^ERNÝ, L. KANDER, J. KLIBERSTRUCTURE AND PROPERTIESOF TITANIUM FOR DENTAL IMPLANTSReceived – Prispjelo: 2008-09-09Received – Prihva}eno: 2009-01-20Original Scientific Paper – Izvorni znanstveni radINTRODUCTIONIt is required that a material for dental implants is biocompatible, it must not be toxic and it may not cause al-lergic reactions 1. It must have high ultimate strengthRm and yield value Rp at low density and low modulusof elasticity E 2. Metallic materials used for dental im-plants comprise alloys of stainless steels, cobalt alloys, ti-tanium (coarse-grained) and titanium alloys 3. Se-mi-products in the form of coarse-grained Ti or Ti alloysare used as bio-material for medical and dental implantssince the second half of the sixties of the last century 4.Titanium is at present preferred to stainless steels and co-balt alloys namely thanks to its excellent bio-compa-tibility 5. Together with high bio-compatibility of Ti itsresistance to corrosion evaluated by polarisation resis-tance varies around the value 103 R/·m 6.It therefore occupies a dominant position from thisviewpoint among materials used for dental implants.In the past years a higher attention was paid also to ti-tanium alloys due to requirements to higher strengthproperties. The reason was the fact that titanium alloyshad higher strength properties in comparison with puretitanium 7. Typical representative of these alloys is du-plex alloy ( a  Ti6Al4V 8. After application of den-tal implants made of these alloys toxicity of vanadiumwas confirmed 9. Aluminium, too, can be categorisedamong potentially toxic elements.During the following development of dental implan-ts the efforts were concentrated on replacement of tita-nium alloys the toxic and potentially toxic elements bynon-toxic elements. That’s why new alloys of the typeTiTa, TiMo, TiNb and TiZr began to be used. Singlephase  Ti alloys were developed at the same time,which are characterised by the low value of the modulusof elasticity 10. Ti alloys with elements with very dif-ferent density and melting temperature (TiTa, TiMo) re-quire special technology of manufacture, by which theysignificantly increase production costs and price ofsemi-products for dental implants.The problem at the development of metallic bio-ma-terials consists not only in their real or potential toxicity,but also in their allergenic potential 11. Sensitivity ofpopulation to allergies keeps increasing. Allergies to met-als is caused by metallic ions which are released frommetals by body fluids. Share of individual metals on initi-ation of allergies is different. What concerns the alloyingelements for dental implants special attention is paidnamely to Ni and Co, as their allergenic effect variesaround (13,5 %) and Cr (9,5 %). Some titanium alloysalso contain the elements classified as allergens. Theseare e.g. the following alloys: Ti13Cu4,5Ni; Ti20Pd5Cr;Ti20Cr0,2Si. Sensitivity of population to Ni is increasing.For these reasons pure titanium still remains to be apreferred material for dental applications. DevelopmentMETALURGIJA 48 (2009) 4, 249-252 249This paper describes manufacture of nano-structural titanium, its structure and properties. Nano-titanium hashigher specific strength properties than ordinary (coarse-grained) titanium. Nano-titanium was produced bythe equal-channel angular pressing (ETAP) process. The research it self was focused on physical base ofstrengthening and softening processes and developments occurring at the grain boundaries during the ECAPprocess at half-hot temperature. Strength of nano-titanium varies around 960 MPa, grain size around 300 nm.Key words:submicrocrystalline structure, severe plastic deformation (SPD), ECAP, structure and properties, ti-taniumStruktura i svojstva titana za zubne umetke (implantate). Rad opisuje proizvodnju nanostrukturnog ti-tana te njegovu strukturu i svojstva. Nanotitan se odlikuje vi{om ~vrsto}om od obi~nog, krupnozrnatog, i proiz-veden je kanalno kutnim pre{anjem (KKP). Samo istra`ivanje bilo je usmjereno na fizikalne osnove procesao~vr{}avanja i omek{avanja na granicama zrna tijekom procesa kanalno kutnim pre{anjem (KKP) na srednjimtemperaturama. ^vrsto}a nanotitana varira oko 960 MPa, a veli~ina zrna je oko 300 nm.Klju~ne rije~i: submikrokristalne strukture, intenzivna plasti~na deformacija (JPD), KKP, strukture i svojstva, ti-tanISSN 0543-5846METABK 48(4) 249-252 (2009)UDC-UDK 539.377:669-122.2:620.17=111M. Greger, M. ^erný, J. Kliber, Faculty of Metallurgy and Materials En-gineering, V[B-TU Ostrava,, Czech RepublicL. Kander, Material & Metallurgical Research Ltd., Ostrava, Czech Re-publictrend in case of this material is oriented on preservationof low value of the modulus of elasticity and on increaseof mechanical properties, especially strength. Accord-ing to the Hall-Petch relation it is possible to increaseconsiderably strength properties of metals by grain re-finement. That’s why it is appropriate to use for dentalimplants rather fine-grained Ti instead of coarse-grai-ned Ti. Use of nano-materials concerns numerous fieldsincluding medicine. Bulk nano-structural metallic mate-rials are used for dental applications. These are materi-als with the grain size smaller than approx. 100 to 300nm 12. High-purity titanium is used for dental im-plants. Chemical composition of CP Ti for dental im-plants must be within the following interval 3.STRUCTURE AND PROPERTIES OF CP TiCommercially pure titanium (CP) bars and sheetswere used in this study. The average grain size of theas-received CP titanium is ASTM no. 4. Tensile speci-mens with a gauge of 50 mm length, 10 mm width and 3,5mm thickness were machined with the tensile axis ori-ented parallel to the final rolling direction. The specimenswere deformed at room temperature with different initialstrain rates. After testing, the deformed specimens in or-der to preserve the microstructure Figure 1- 4. Specimenswere sectioned along the gauge and grip parts of the de-formed sample. The samples were then polished etchedusing 10 % HF, 10 % HNO3 and 80 % H2O for 20 second.Chemical analysis and mechanical properties commer-cially pure (CP) titanium are given in the Table 1-3.PROPERTIES OF NANO-TITANIUM (N)TiNano-titanium is characterised by exceptional me-chanical properties, among which high ultimate strengthand high yield value are of utmost importance. Strengthproperties of (n)Ti must have the following values: Rm >1000 MPa, Rp0,2 > 850 MPa 6. Apart from the strength,another important properties of dental implants is theirso called specific strength (strength related to density).Mechanical properties of metallic material for implants250 METALURGIJA 48 (2009) 4, 249-252M. GREGER et al.: STRUCTURE AND PROPERTIES OF TITANIUM FOR DENTAL IMPLANTSFigure 1. Initial microstructure of CP Ti (longitudinal di-rection)Figure 2. Initial microstructure of Ti (transverse direction)Table 1. Chemical analysis commercially pur etita-nium (CP), (weight %)N O C Fe Al Cr Ti0,004 0,068 0,008 0,03 0,01 0,01 Rest.Table 2. Tensile properties of CP titanium after anne-aling 649 C °/1 hour (ASTM E8)Tensilestrength RmRp0,2 YieldstrengthElongation 2“gageReduction ofarea/ MPa / MPa / % / %365 212 51 71Table 3. Initial hardness of commercially pure Ti andhardness after cold rollingLabelDiagonal of inden-tion d / mHV30Sample nr. 1659 128632 139652 131Sample nr. 2658 128655 130658 128Sample nr. 3.527 200525 202535 194Figure 3. Microstructure of Ti after cold rolling (longitu-dinal direction)are evaluated in relation to its density as so called spe-cific properties. In case of classical coarse-grained tita-nium the relation (Rm/) varies around 70 to 120 N·m/g,for the alloy Ti6Al4V it varies around 200 N·m/g13,14, and for (n)Ti it is possible to predict the valuesRm/ = 270 Ν·m/g. As a matter of interest it is possible togive the specific strength also for some other dental ma-terials: steel AISI 316L- Rm/ = 65 Ν·m/g, cobalt alloys -Rm/ = 160 ·m/g, Ti (Ti15Mo5Zr) - Rm/ = 180N·m/g. Disadvantage of dental implants based on steelor cobalt alloys is their high tensile modulus of elastic-ity: E = 200 to 240 GPa, while in case of titanium and itsalloys this value varies between 80 and 120 GPa 15,16.At present only few companies in the world manu-facture commercially bulk nano-materials.THE TECHNOLOGY FOR MANUFACTUREOF NANOSTRUCTURE TITANIUM (N)TiThe main objective of experiments was manufactureof (n)Ti, description and optimisation of its propertiesfrom the viewpoint of their bio-compability, resistance tocorrosion, strength and other mechanical properties fromthe viewpoint of its application in dental implants. Chem-ical purity of semi products for (n)Ti was ensured bytechnology of melting in vacuum and by zonal remelting.The obtained semi-product was under defined parametersof forming processed by the ECAP technology. The out-put was nano-structural titanium with strength about1050 MPa. The obtained (n)Ti was further processed bytechnology (of rotation forging) and drawing to the shapesuitable for dental implants. Sequence of production of(n)Ti is described in the Table 4.OBTAINED RESULTSAND THEIR ANALYSISSemi products from individual heats were processedaccording to modified programs by the ECAP technol-ogy and then drawn to a wire. Wire diameter variedabout 4 - 5 mm 17-19.ECAP technology and drawing was made in severalvariants:a) 2 to 5 passes ECAP at a temperatures of 450 oC.b) 2 to 5 passes ECAP at a temperatures of 370 oC.c) 10 passes ECAP at a temperatures of 280 oC; withannealing between individual passes.d) rotation re-forging to a diameter of 10 mm (coldforming : e = 2,2).e) rotation re-forging to a diameter of 6 mm (coldforming : e = 1,02).f) The following technology of drawing was real-ised at increased temperatures.The samples for mechanical tests and for mi-cro-structural analyses were prepared from individualvariants of processing. On the basis of the results, partic-ularly the obtained strength values, several variantswere chosen for more detailed investigation of develop-ments occurring in the structure at application of theECAP and subsequent drawing after heat treatment.Structure of (n)Ti after application of the ECAP processis shown in the Figure 5, 6 and Figure 7. The structurewas analysed apart from light microscopy also by theX-ray diffraction. Table 5 summarises the obtained ba-sic mechanical properties.METALURGIJA 48 (2009) 4, 249-252 251M. GREGER et al.: STRUCTURE AND PROPERTIES OF TITANIUM FOR DENTAL IMPLANTSFigure 4. Microstructure of Ti after cold rolling (transver-se direction)Table 4. Basic diagram of manufacture of (n)Tin Operation1.Melting and casting of Ti in vacuum furnace.Semi product in the form of a bar:Dmin = 35 mm.Lmin = 130 mm.2.Refining. Production of high purity semi product forECAP.Chemical composition – Table 1.3.ECAP process:• Bar with  30 mm• Number of passes: 12• Load on extruding punch – Pmax = 1500 MPa,• T = 280 °C• Time = 120 s.4.Mechanical properties:• Rm = 960 MPa,• E = 100 GPa,• A = 12 %,• dz = 100 to 300 nm.5.Rotation re-forging and drawing of (n)Ti to a wire:Dd = 6 mm.6.Mechanical properties:• Rm  1030 MPa,• Structure strengthened by deformation.Table 5. Mechanical properties (n)Ti after ecap and dra-wingFormingprocessedRm/MPaA/%E/GPadz/nmECAP(10 passes)960 12 100100 to300Drawing(Dd = 6 mm)1030 to10509 100100 to300CONCLUSIONTechnology of manufacture of nano-titanium wasproposed and experimentally verified. Grain refinementin input materials was obtained using the ECAP process.In conformity with the Hall-Petch, relation the strengthproperties of Ti increased significantly as a result ofgrain refinement. The obtained mechanical propertiescorrespond with the declared requirements. Nano-tita-nium has higher specific strength properties than ordi-nary titanium. Strength of nano-titanium varies around1250 MPa, grain size around 300 nm.The authors would like to express their gratitude forfinancial support of the Grant Agency of Czech Republic106/091598, 106/07/0631, MSM6198910013.REFERENCES1 J. Marciniak, Biomaterials, Edited by Silesian University ofTechnology, Gliwice, 2002.2 M. Gierzyòskia-Dolna et al, Titanium and its alloys. Proces-sing and application in technology and medicine, Edited byCzestochowa University of Technology, Czestochowa, 2002.3 R. Hunter, F. Alister, J. Mõller, J. Alister, Journal of Achie-vements in Materials and Manufacturing Engineering 22(2007) 1, 77-80.4 V. Stoyka, F. Kovac, B. Julius, Metalurgija, 48 (2009) 2,99-102.5 D. Krupa, J. Baszkiewicz, J. Sobczak, A. Bilinsk, A. Barcz,Journal of Materials Processing Technology 143-144(2003), 158-163.6 P. Fajfar, Metalurgija 45 (2006) 3, 239-241.7 A. Kieizkowska, E. Krasicka-Cydzik, M. Jenek, Biomate-rials Engineering 47-53 (2005), 146-148.8 M. @itòanský, L. ^aplovi~, M. Greger, Proceedings of the10th Scientific International Conference “Achievements inMechanical and Materials Engeneering” AMME ´2002,Gliwice – Zakopane, 2002, 631-636.9 M. J. Tan, X. J. Zhu, Journal of Achievements and Manu-facturing Engineering 18,1-2 (2006), 183-186.10 D. Kurda, M. Nikomu, M. Morinaga, Y. Kato, T. Yashiro,Materials Science and Engineering A243 (1998), 244-249.11 A. Baron, D. Szewieczek, R. Nowosielski, Journal ofAchievements in Materials and Manufacturing Engineering20 (2007) 1-2, 83-86.12 J. Zrník, I. Mamuzi}, S. V. Dobatkin, Z. Stejskal, L. Kraus,Metallurgia 46 (2007) 1, 21-27.13 S. V. Dobatkin, J. Zrník, I. Mamuzi}, Metalurgija 45 (2006)4, 313-321.14 M. @itòansky, L. ^aplovi~, L. Rehák, F. Makai, Journal ofAchievements in Materials and Manufacturing Engineering24 (2007) 1, 146-152.15 J. Adamus, Archives of Materials Science and Engineering28 (2007) 5, 313-316.16 J. Zrník, I. Mamuzi}, S. V. Dobatkin, Metalurgija 45 (2006)4, 323-331.17 M. Greger, R. Kocich, L. ^í`ek, L. A. Dobrzanski, M.Wi-domská, Science and Engineering 28 (2007), 709-716.18 L. Kander, M. Greger : Fatique Properties of AISI 316 Gra-de Steel after ECAP Technology, Proceedings of 17th Euro-pean Conference on Fracture Multilevel Approach to Frac-ture of Materials, Components and Structures. VUTIUM,Brno 2008, 2429-2436.19 M. Greger, R. Kocich, L. ^í`ek, L. A. Dobrzanski, M. Wi-domská, B. Kuøetová, A. Silbernagel, Journal of Achieve-ments in Materials and Manufacturing Engineering 18(2006) 1-2, 103-106.Note: Translation of the paper: Ing. B. [kandera, Dobrá, Czech Republic252 METALURGIJA 48 (2009) 4, 249-252M. GREGER et al.: STRUCTURE AND PROPERTIES OF TITANIUM FOR DENTAL IMPLANTSFigure 5. Microstructure of (n)Ti after ECAP (2 passes;longitudinal direction)Figure 6. Microstructure of (n)Ti after ECAP (2 passes;transverse direction)Figure 7. Microstructure of (n)Ti after ECAP (10 passes)

English

Struktura i svojstva titana za zubne umetke (implantate)

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M. GREGER, M. ^ERNÝ, L. KANDER, J. KLIBERSTRUCTURE AND PROPERTIESOF TITANIUM FOR DENTAL IMPLANTSReceived – Prispjelo: 2008-09-09Received – Prihva}eno: 2009-01-20Original Scientific Paper – Izvorni znanstveni radINTRODUCTIONIt is required that a material for dental implants is biocompatible, it must not be toxic and it may not cause al-lergic reactions 1. It must have high ultimate strengthRm and yield value Rp at low density and low modulusof elasticity E 2. Metallic materials used for dental im-plants comprise alloys of stainless steels, cobalt alloys, ti-tanium (coarse-grained) and titanium alloys 3. Se-mi-products in the form of coarse-grained Ti or Ti alloysare used as bio-material for medical and dental implantssince the second half of the sixties of the last century 4.Titanium is at present preferred to stainless steels and co-balt alloys namely thanks to its excellent bio-compa-tibility 5. Together with high bio-compatibility of Ti itsresistance to corrosion evaluated by polarisation resis-tance varies around the value 103 R/·m 6.It therefore occupies a dominant position from thisviewpoint among materials used for dental implants.In the past years a higher attention was paid also to ti-tanium alloys due to requirements to higher strengthproperties. The reason was the fact that titanium alloyshad higher strength properties in comparison with puretitanium 7. Typical representative of these alloys is du-plex alloy ( a  Ti6Al4V 8. After application of den-tal implants made of these alloys toxicity of vanadiumwas confirmed 9. Aluminium, too, can be categorisedamong potentially toxic elements.During the following development of dental implan-ts the efforts were concentrated on replacement of tita-nium alloys the toxic and potentially toxic elements bynon-toxic elements. That’s why new alloys of the typeTiTa, TiMo, TiNb and TiZr began to be used. Singlephase  Ti alloys were developed at the same time,which are characterised by the low value of the modulusof elasticity 10. Ti alloys with elements with very dif-ferent density and melting temperature (TiTa, TiMo) re-quire special technology of manufacture, by which theysignificantly increase production costs and price ofsemi-products for dental implants.The problem at the development of metallic bio-ma-terials consists not only in their real or potential toxicity,but also in their allergenic potential 11. Sensitivity ofpopulation to allergies keeps increasing. Allergies to met-als is caused by metallic ions which are released frommetals by body fluids. Share of individual metals on initi-ation of allergies is different. What concerns the alloyingelements for dental implants special attention is paidnamely to Ni and Co, as their allergenic effect variesaround (13,5 %) and Cr (9,5 %). Some titanium alloysalso contain the elements classified as allergens. Theseare e.g. the following alloys: Ti13Cu4,5Ni; Ti20Pd5Cr;Ti20Cr0,2Si. Sensitivity of population to Ni is increasing.For these reasons pure titanium still remains to be apreferred material for dental applications. DevelopmentMETALURGIJA 48 (2009) 4, 249-252 249This paper describes manufacture of nano-structural titanium, its structure and properties. Nano-titanium hashigher specific strength properties than ordinary (coarse-grained) titanium. Nano-titanium was produced bythe equal-channel angular pressing (ETAP) process. The research it self was focused on physical base ofstrengthening and softening processes and developments occurring at the grain boundaries during the ECAPprocess at half-hot temperature. Strength of nano-titanium varies around 960 MPa, grain size around 300 nm.Key words:submicrocrystalline structure, severe plastic deformation (SPD), ECAP, structure and properties, ti-taniumStruktura i svojstva titana za zubne umetke (implantate). Rad opisuje proizvodnju nanostrukturnog ti-tana te njegovu strukturu i svojstva. Nanotitan se odlikuje vi{om ~vrsto}om od obi~nog, krupnozrnatog, i proiz-veden je kanalno kutnim pre{anjem (KKP). Samo istra`ivanje bilo je usmjereno na fizikalne osnove procesao~vr{}avanja i omek{avanja na granicama zrna tijekom procesa kanalno kutnim pre{anjem (KKP) na srednjimtemperaturama. ^vrsto}a nanotitana varira oko 960 MPa, a veli~ina zrna je oko 300 nm.Klju~ne rije~i: submikrokristalne strukture, intenzivna plasti~na deformacija (JPD), KKP, strukture i svojstva, ti-tanISSN 0543-5846METABK 48(4) 249-252 (2009)UDC-UDK 539.377:669-122.2:620.17=111M. Greger, M. ^erný, J. Kliber, Faculty of Metallurgy and Materials En-gineering, V[B-TU Ostrava,, Czech RepublicL. Kander, Material & Metallurgical Research Ltd., Ostrava, Czech Re-publictrend in case of this material is oriented on preservationof low value of the modulus of elasticity and on increaseof mechanical properties, especially strength. Accord-ing to the Hall-Petch relation it is possible to increaseconsiderably strength properties of metals by grain re-finement. That’s why it is appropriate to use for dentalimplants rather fine-grained Ti instead of coarse-grai-ned Ti. Use of nano-materials concerns numerous fieldsincluding medicine. Bulk nano-structural metallic mate-rials are used for dental applications. These are materi-als with the grain size smaller than approx. 100 to 300nm 12. High-purity titanium is used for dental im-plants. Chemical composition of CP Ti for dental im-plants must be within the following interval 3.STRUCTURE AND PROPERTIES OF CP TiCommercially pure titanium (CP) bars and sheetswere used in this study. The average grain size of theas-received CP titanium is ASTM no. 4. Tensile speci-mens with a gauge of 50 mm length, 10 mm width and 3,5mm thickness were machined with the tensile axis ori-ented parallel to the final rolling direction. The specimenswere deformed at room temperature with different initialstrain rates. After testing, the deformed specimens in or-der to preserve the microstructure Figure 1- 4. Specimenswere sectioned along the gauge and grip parts of the de-formed sample. The samples were then polished etchedusing 10 % HF, 10 % HNO3 and 80 % H2O for 20 second.Chemical analysis and mechanical properties commer-cially pure (CP) titanium are given in the Table 1-3.PROPERTIES OF NANO-TITANIUM (N)TiNano-titanium is characterised by exceptional me-chanical properties, among which high ultimate strengthand high yield value are of utmost importance. Strengthproperties of (n)Ti must have the following values: Rm >1000 MPa, Rp0,2 > 850 MPa 6. Apart from the strength,another important properties of dental implants is theirso called specific strength (strength related to density).Mechanical properties of metallic material for implants250 METALURGIJA 48 (2009) 4, 249-252M. GREGER et al.: STRUCTURE AND PROPERTIES OF TITANIUM FOR DENTAL IMPLANTSFigure 1. Initial microstructure of CP Ti (longitudinal di-rection)Figure 2. Initial microstructure of Ti (transverse direction)Table 1. Chemical analysis commercially pur etita-nium (CP), (weight %)N O C Fe Al Cr Ti0,004 0,068 0,008 0,03 0,01 0,01 Rest.Table 2. Tensile properties of CP titanium after anne-aling 649 C °/1 hour (ASTM E8)Tensilestrength RmRp0,2 YieldstrengthElongation 2“gageReduction ofarea/ MPa / MPa / % / %365 212 51 71Table 3. Initial hardness of commercially pure Ti andhardness after cold rollingLabelDiagonal of inden-tion d / mHV30Sample nr. 1659 128632 139652 131Sample nr. 2658 128655 130658 128Sample nr. 3.527 200525 202535 194Figure 3. Microstructure of Ti after cold rolling (longitu-dinal direction)are evaluated in relation to its density as so called spe-cific properties. In case of classical coarse-grained tita-nium the relation (Rm/) varies around 70 to 120 N·m/g,for the alloy Ti6Al4V it varies around 200 N·m/g13,14, and for (n)Ti it is possible to predict the valuesRm/ = 270 Ν·m/g. As a matter of interest it is possible togive the specific strength also for some other dental ma-terials: steel AISI 316L- Rm/ = 65 Ν·m/g, cobalt alloys -Rm/ = 160 ·m/g, Ti (Ti15Mo5Zr) - Rm/ = 180N·m/g. Disadvantage of dental implants based on steelor cobalt alloys is their high tensile modulus of elastic-ity: E = 200 to 240 GPa, while in case of titanium and itsalloys this value varies between 80 and 120 GPa 15,16.At present only few companies in the world manu-facture commercially bulk nano-materials.THE TECHNOLOGY FOR MANUFACTUREOF NANOSTRUCTURE TITANIUM (N)TiThe main objective of experiments was manufactureof (n)Ti, description and optimisation of its propertiesfrom the viewpoint of their bio-compability, resistance tocorrosion, strength and other mechanical properties fromthe viewpoint of its application in dental implants. Chem-ical purity of semi products for (n)Ti was ensured bytechnology of melting in vacuum and by zonal remelting.The obtained semi-product was under defined parametersof forming processed by the ECAP technology. The out-put was nano-structural titanium with strength about1050 MPa. The obtained (n)Ti was further processed bytechnology (of rotation forging) and drawing to the shapesuitable for dental implants. Sequence of production of(n)Ti is described in the Table 4.OBTAINED RESULTSAND THEIR ANALYSISSemi products from individual heats were processedaccording to modified programs by the ECAP technol-ogy and then drawn to a wire. Wire diameter variedabout 4 - 5 mm 17-19.ECAP technology and drawing was made in severalvariants:a) 2 to 5 passes ECAP at a temperatures of 450 oC.b) 2 to 5 passes ECAP at a temperatures of 370 oC.c) 10 passes ECAP at a temperatures of 280 oC; withannealing between individual passes.d) rotation re-forging to a diameter of 10 mm (coldforming : e = 2,2).e) rotation re-forging to a diameter of 6 mm (coldforming : e = 1,02).f) The following technology of drawing was real-ised at increased temperatures.The samples for mechanical tests and for mi-cro-structural analyses were prepared from individualvariants of processing. On the basis of the results, partic-ularly the obtained strength values, several variantswere chosen for more detailed investigation of develop-ments occurring in the structure at application of theECAP and subsequent drawing after heat treatment.Structure of (n)Ti after application of the ECAP processis shown in the Figure 5, 6 and Figure 7. The structurewas analysed apart from light microscopy also by theX-ray diffraction. Table 5 summarises the obtained ba-sic mechanical properties.METALURGIJA 48 (2009) 4, 249-252 251M. GREGER et al.: STRUCTURE AND PROPERTIES OF TITANIUM FOR DENTAL IMPLANTSFigure 4. Microstructure of Ti after cold rolling (transver-se direction)Table 4. Basic diagram of manufacture of (n)Tin Operation1.Melting and casting of Ti in vacuum furnace.Semi product in the form of a bar:Dmin = 35 mm.Lmin = 130 mm.2.Refining. Production of high purity semi product forECAP.Chemical composition – Table 1.3.ECAP process:• Bar with  30 mm• Number of passes: 12• Load on extruding punch – Pmax = 1500 MPa,• T = 280 °C• Time = 120 s.4.Mechanical properties:• Rm = 960 MPa,• E = 100 GPa,• A = 12 %,• dz = 100 to 300 nm.5.Rotation re-forging and drawing of (n)Ti to a wire:Dd = 6 mm.6.Mechanical properties:• Rm  1030 MPa,• Structure strengthened by deformation.Table 5. Mechanical properties (n)Ti after ecap and dra-wingFormingprocessedRm/MPaA/%E/GPadz/nmECAP(10 passes)960 12 100100 to300Drawing(Dd = 6 mm)1030 to10509 100100 to300CONCLUSIONTechnology of manufacture of nano-titanium wasproposed and experimentally verified. Grain refinementin input materials was obtained using the ECAP process.In conformity with the Hall-Petch, relation the strengthproperties of Ti increased significantly as a result ofgrain refinement. The obtained mechanical propertiescorrespond with the declared requirements. Nano-tita-nium has higher specific strength properties than ordi-nary titanium. Strength of nano-titanium varies around1250 MPa, grain size around 300 nm.The authors would like to express their gratitude forfinancial support of the Grant Agency of Czech Republic106/091598, 106/07/0631, MSM6198910013.REFERENCES1 J. Marciniak, Biomaterials, Edited by Silesian University ofTechnology, Gliwice, 2002.2 M. Gierzyòskia-Dolna et al, Titanium and its alloys. Proces-sing and application in technology and medicine, Edited byCzestochowa University of Technology, Czestochowa, 2002.3 R. Hunter, F. Alister, J. Mõller, J. Alister, Journal of Achie-vements in Materials and Manufacturing Engineering 22(2007) 1, 77-80.4 V. Stoyka, F. Kovac, B. Julius, Metalurgija, 48 (2009) 2,99-102.5 D. Krupa, J. Baszkiewicz, J. Sobczak, A. Bilinsk, A. Barcz,Journal of Materials Processing Technology 143-144(2003), 158-163.6 P. Fajfar, Metalurgija 45 (2006) 3, 239-241.7 A. Kieizkowska, E. Krasicka-Cydzik, M. Jenek, Biomate-rials Engineering 47-53 (2005), 146-148.8 M. @itòanský, L. ^aplovi~, M. Greger, Proceedings of the10th Scientific International Conference “Achievements inMechanical and Materials Engeneering” AMME ´2002,Gliwice – Zakopane, 2002, 631-636.9 M. J. Tan, X. J. Zhu, Journal of Achievements and Manu-facturing Engineering 18,1-2 (2006), 183-186.10 D. Kurda, M. Nikomu, M. Morinaga, Y. Kato, T. Yashiro,Materials Science and Engineering A243 (1998), 244-249.11 A. Baron, D. Szewieczek, R. Nowosielski, Journal ofAchievements in Materials and Manufacturing Engineering20 (2007) 1-2, 83-86.12 J. Zrník, I. Mamuzi}, S. V. Dobatkin, Z. Stejskal, L. Kraus,Metallurgia 46 (2007) 1, 21-27.13 S. V. Dobatkin, J. Zrník, I. Mamuzi}, Metalurgija 45 (2006)4, 313-321.14 M. @itòansky, L. ^aplovi~, L. Rehák, F. Makai, Journal ofAchievements in Materials and Manufacturing Engineering24 (2007) 1, 146-152.15 J. Adamus, Archives of Materials Science and Engineering28 (2007) 5, 313-316.16 J. Zrník, I. Mamuzi}, S. V. Dobatkin, Metalurgija 45 (2006)4, 323-331.17 M. Greger, R. Kocich, L. ^í`ek, L. A. Dobrzanski, M.Wi-domská, Science and Engineering 28 (2007), 709-716.18 L. Kander, M. Greger : Fatique Properties of AISI 316 Gra-de Steel after ECAP Technology, Proceedings of 17th Euro-pean Conference on Fracture Multilevel Approach to Frac-ture of Materials, Components and Structures. VUTIUM,Brno 2008, 2429-2436.19 M. Greger, R. Kocich, L. ^í`ek, L. A. Dobrzanski, M. Wi-domská, B. Kuøetová, A. Silbernagel, Journal of Achieve-ments in Materials and Manufacturing Engineering 18(2006) 1-2, 103-106.Note:Translation of the paper: Ing. B. [kandera, Dobrá, Czech Republic252 METALURGIJA 48 (2009) 4, 249-252M. GREGER et al.: STRUCTURE AND PROPERTIES OF TITANIUM FOR DENTAL IMPLANTSFigure 5. Microstructure of (n)Ti after ECAP (2 passes;longitudinal direction)Figure 6. Microstructure of (n)Ti after ECAP (2 passes;transverse direction)Figure 7. Microstructure of (n)Ti after ECAP (10 passes)

Struktura i svojstva titana za zubne umetke (implantate)

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