Malzeme Bilimi ve Mühendisliği Bölümü

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Citation Count: Kuntsmann, J...et al. (2011). Stability of edge states and edge magnetism in graphene nanoribbons. Physical Review B, 83(4). http://dx.doi.org/10.1103/PhysRevB.83.045414
Stability of edge states and edge magnetism in graphene nanoribbons
(Amer Physical Soc, 2011) Kuntsmann, Jens; Özdoğan, Cem; Quandt, Alexander; Fehske, Holger
We critically discuss the stability of edge states and edge magnetism in zigzag edge graphene nanoribbons (ZGNRs). We point out that magnetic edge states might not exist in real systems and show that there are at least three very natural mechanisms-edge reconstruction, edge passivation, and edge closure-which dramatically reduce the effect of edge states in ZGNRs or even totally eliminate them. Even if systems with magnetic edge states could be made, the intrinsic magnetism would not be stable at room temperature. Charge doping and the presence of edge defects further destabilize the intrinsic magnetism of such systems
Citation Count: Akman, N...et al. (2011). Ionization energies, Coulomb explosion, fragmentation, geometric, and electronic structures of multicharged boron clusters B-n (n=2-13). Physical Review B , 84(7). http://dx.doi.org/10.1103/PhysRevB.84.075463
Ionization energies, Coulomb explosion, fragmentation, geometric, and electronic structures of multicharged boron clusters B-n (n=2-13)
(Amer Physical Soc, 2011) Akman, Nurten; Taş, Murat; Özdoğan, Cem; Boustani, Ihsan; 27617
Based on the ab initio quantum chemical methods, we have determined fragmentation channels, ionization energies, and the Coulomb explosion of multicharged boron clusters B-n (n = 2-13), where n is the cluster size. The electron-deficient boron clusters sustain more stability and hardly fragment when they are negatively charged. Stability of boron clusters decreases with increasing ionization. Only by the first ionization the odd-size clusters are more stable than the even-size clusters. Further ionizations cause the repulsive Coulomb force between the constituent atoms to get stronger, and lead first to metastable states, then to the Coulomb explosion of clusters. None of the cationic boron clusters studied remain stable after six times ionization. The critical charge for metastability is estimated as Q(m) <= n/2 for even-size clusters, and Q(m) <= 1/2 (n - 1) for odd-size clusters. In addition, the critical charge for the Coulomb explosion is found to be Q(c) = n/2 + 1 for even-size clusters, and Q(c) = 1/2(n + 1) for odd-size clusters. Relative stability of clusters with respect to their nearest neighbors is determined from the analysis of their second energy difference data. Several dissociation channels of B-n(+) and B-13(Q) isomers with the lowest fragmentation energies are presented. All of the vibrational frequencies are found positive indicating that no transition state is possible for the clusters studied. Reliability of our data is verified with a good agreement with experimental results
Citation Count: Yüksektepe, Ç...et al. (2011). "Synthesis, molecular structure and DFT study of 2-(N-Benzoylbenzamido)pyridine-3-yl benzoate". Journal of Chemical Crystallograpy, 41(10), 1520-1527. http://dx.doi.org/10.1007/s10870-011-0134-3
Synthesis, molecular structure and DFT study of 2-(N-Benzoylbenzamido)pyridine-3-yl benzoate
(Springer/Plenum Publishers, 2011) Yüksektepe, Çiğdem; Kazak, Canan; Özdoğan, Cem; Güvenç, Ziya B.; Büyükgüngör, Orhan; Arslan, Figen; Odabaşoğlu, Mustafa; 42359; 22620; 4292; 49272; 13249
The biologically important 2-amino-3-hydroxypyridine reacts with benzoyl chloride to give 2-(N-benzoylbenzamido)pyridine-3-yl benzoate. This synthesized compound has been studied by elemental analysis, X-ray crystallography and also theoretically by density functional theory (DFT) framework with B3LYP/6-311++G(d, p) level of theory. The molecules of this compound crystallize in the orthorhombic space group of P2(1)2(1)2(1) and the crystal packing involves both hydrogen-bonding and C-Ha <-pi interaction. The vibrational normal modes of the molecular structure are investigated by ab initio method for both infrared intensities (IR) and for Raman activities. Furthermore, the corresponding assignments are discussed. Hydrogen and carbon atoms of the benzene rings are found to be highly active. Also, experimentally obtained IR spectrum is presented and compared with the available theoretical data. Experimentally and theoretically obtained IR spectrum are in good agreement
Citation Count: Esen, Ziya, "TiNi Reinforced Magnesium Composites by Powder Metallurgy", Magnesium Technology 2011, pp. 457-462, (2011)
Tini Reinforced Magnesium Composites By Powder Metallurgy
(John Wiley and Sons LTD., 2011) Esen, Ziya; 52373
Rod shaped Mg-TiNi composite samples were manufactured bypowder metallurgical route in which the samples were heated and deformed simultaneously using rotary hot swaging technique. Firstly, encapsulated argon filled copper tubes which contained compacts of pure magnesium and pre-alloyed TiNi alloy powder mixtures were deformed about 45% in two steps at 450 degrees C. Pre/post annealing heat treatments were applied at 450 degrees C for 20 mins between the stages of coaxial deformation to enhance the sintering degree and to homogenize the heavily deformed composite structures. Next, copper peeled and machined samples were compression tested under quasi-static conditions to investigate the mechanical properties, i.e. yield and peak strength, and ductility. Transmission and Scanning Electron Microscopy studies were carried out to examine the Mg-TiNi interface and fracture surfaces of the compression tested composites, respectively.
Citation Count: Esen, Z., Bor, Ş. (2011). Characterization of Ti-6Al-4V alloy foams synthesized by space holder technique. Materials science and engineering a-structural materials properties microstructure and processing, 528(7-8), 3200-3209. http://dx.doi.org/10.1016/j.msea.2011.01.008
Characterization of Ti-6Al-4V alloy foams synthesized by space holder technique
(Elsevier Science S A, 2011) Esen, Ziya; Bor, Şakir; 52373
Ti-6Al-4V foams, biomedical candidate materials, were synthesized by powder metallurgical space holder technique as a result of evaporation of magnesium to achieve desired porosity content. Final products contained porosities in the range similar to 43-64% with an average macropore size between 485 and 572 mu m and a lamellar type Widmanstatten microstructure composed of alpha-platelets and beta-laths. Unlike the case of bulk Ti-6Al-4V alloy tested under compression loading, compression stress-strain curves of manufactured Ti-6Al-4V foams were similar to those of elastic-plastic foams, which contain a linear elastic region; a plateau stage: and a densification stage. In the plateau region deformation bands perpendicular to the compression axis were developed and cell collapsing took place together with the buckling and fracture of some of the cell walls and edges in a ductile manner. Calculated elastic modulus and yield strength were in the range 1.42-14.7 GPa and 28.2-150 MPa, respectively, and the foam mechanical properties were found to be dependent on micro porous cell wall properties, which in turn depends on neck size between powder particles. Around 330 MPa yield strength value was calculated for porous cell walls by the use of Ti-6Al-4V alloy powder samples sintered in loose and compacted conditions, which were utilized to simulate the cell wall structure of foams. In addition, overall mechanical properties of foam s were investigated considering macro porosity fraction, p(macro), and the yield strength of foams exhibited a power law dependence, similar to commonly used minimum solid area models, in the form of A*(1 - p(marco))(n), where the proportionality constant "A" was found to be the yield strength of micro porous cell walls
Citation Count: Esen, Ziya, "The effect of processing routes on the structure and properties of magnesium-TiNi composites", Vol. 558, pp. 632-640, (2012)
The Effect of Processing Routes On the Structure and Properties of Magnesium-Tini Composites
(Elsevier Science SA, 2012) Esen, Ziya; 52373
TiNi particulate-reinforced magnesium matrix composites were fabricated by rotary hot swaging and post-annealing heat treatment. The magnesium matrix of the processed composites was observed to contain elongated grains comprised of equiaxed recrystallised grains. Each elongated grain was surrounded by thin, non-continuous magnesium oxide layers composed of nanometric magnesium oxide particles. The TiNi reinforcement particles preserved their starting spherical shape during processing and testing. However, the hot deformation and annealing heat treatment changed the underlying room temperature microstructures and transformation behaviours of the reinforcements. In contrast to the majority of the ceramic reinforcements, the ductility of the composites was not significantly degraded by the addition of TiNi reinforcements; conversely, an approximately 25% enhancement was recorded in the elongation values for the Mg-5 vol% TiNi alloy. While the yield strengths of the composites changed linearly with increasing reinforcement content, the highest compression peak strength value was obtained with the addition of 5 vol% TiNi, beyond which the strength was slightly decreased. During mechanical testing, the TiNi particles debonded due to insufficient bonding between the matrix and reinforcement, and fracture resulted largely within the oxide layers present in the interfacial region and the magnesium oxide film in the magnesium grain boundaries. (C) 2012 Elsevier B.V. All rights reserved.
Citation Count: Taş, Murat..at all (2012). "Fragmentation and Coulomb explosion of multicharged small boron clusters", Physical Review B - Condensed Matter and Materials Physics, Vol. 85, No. 23.
Fragmentation and Coulomb explosion of multicharged small boron clusters
(2012) Taş, Murat; Akman, Nurten; Özdoǧan, Cem; Boustani, Ihsan; 40569
We extensively study the fragmentation and Coulomb explosion of multiply charged small boron clusters B n (n=2-13), where n is the cluster size. Our calculations are based on ab initio quantum-chemistry methods. Highly charged unstable clusters dissociate spontaneously into several neutral or charged fragments, and large amounts of energy are produced, depending on the charge of the parent cluster. We argue that this mechanism makes boron clusters a clean, safe, and cheap energetic material. © 2012 American Physical Society.
Citation Count: Kalay, Y. E...et al. "Local chemical and topological order in Al-Tb and its role in controlling nanocrystal formation", Acta Materialia, Vol. 60, No. 3, pp. 994-1003, (2012)
Local Chemical and Topological Order in Al-Tb And its Role in Controlling Nanocrystal Formation
(Pergamon-Elsevier Science LTD, 2012) Kalay, Y. E.; Kalay, I.; Hwang, Jinwoo; Voyles, P. M.; Kramer, M. J.; 101579
How the chemical and topological short- to medium-range order develops in Al-Tb glass and its ultimate effect on the control of the high number density of face-centered-cubic-Al (fcc-Al) nuclei during devitrification are described. A combined study using high-energy X-ray diffraction (HEXRD), atom probe tomography (APT), transmission electron microscopy and fluctuation electron microscopy (FEM) was conducted in order to resolve the local structure in amorphous Al90Tb10. Reverse Monte Carlo simulations and Voronoi tessellation analysis based on HEXRD experiments revealed a high coordination of Al around Tb atoms in both liquid and amorphous states. APT results show Al-rich and Al-depleted regions within the as-quenched alloy. A network structure of Tb-rich clusters divides the matrix into nanoscale regions where Al-rich clusters are isolated. It is this finely divided network which allows the amorphous structure to form. Al-rich regions are the locus for fcc-Al crystallization, which occurs before the intermetallic crystallization. FEM reveals medium-range ordered regions similar to 2 nm in diameter, consistent with fcc-Al and trigonal-like Al3Tb crystal structures. We propose that the high coordination of Al around Tb limits diffusion in the intermetallic network, allowing for the isolated Al-rich regions to form at high density. These regions are responsible for the extremely high density of Al nanocrystal nuclei. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Citation Count: Hwang, Jinwoo...et al. (2012). "Nanoscale structure and structural relaxation in Zr 50Cu 45Al 5 bulk metallic glass", Physical Review Letters, Vol. 108, No. 19.
Nanoscale structure and structural relaxation in Zr 50Cu 45Al 5 bulk metallic glass
(2012) Hwang, Jinwoo; Melgarejo, Z.H.; Kalay, Y.E.; Kalay, İlkay; Kramer, M.J.; Stone, D.S.; Voyles, P.M.; 101579
Hybrid reverse Monte Carlo simulations of the structure of Zr 50Cu 45Al 5 bulk metallic glass incorporating medium-range structure from fluctuation electron microscopy data and short-range structure from an embedded atom potential produce structures with significant fractions of icosahedral- and crystal-like atomic clusters. Similar clusters group together into nanometer-scale regions, and relaxation transforms crystal-like clusters into icosahedral clusters. A model refined against only the potential does not agree with the fluctuation microscopy data and contains few crystal-like clusters. © 2012 American Physical Society.
Citation Count: 8Esen, Z.; Dikici, Burak; Duygulu, Ozgur;..et.al., "Titanium-magnesium based composites: mechanical propertiesand in-vitro corrosion response in ringer's solution" Materials Science And Engineering A-Structural Materials Properties Microstructure And Processing, Vol.573, pp.119-126, (2013).
Titanium-magnesium based composites: mechanical propertiesand in-vitro corrosion response in ringer's solution
(Elsevier Science BV, 2013) Esen, Z; Dikici, Burak; Duygulu, Özgür; Dericioğlu, Arcan F.; 52373
Ti-Mg composite rods exhibiting both bioinert and biodegradable characteristics have been manufactured by hot rotary swaging from elemental powders of titanium and magnesium. As a result of processing, spherical magnesium powders elongated in the direction of deformation and the dendritic structure in starting magnesium powders transformed into highly equiaxed grains. Magnesium particles in the outer layer of the composites were decorated by thin layer of MgO while the interior parts were free from oxides. As expected, Young's moduli, yield and peak strengths of the composites were observed to decrease with an increase in the magnesium content, while ductility of composites was enhanced by decreasing the amount of titanium. Composites fractured at an angle 45 to the loading axis along the titanium particle boundaries and through the magnesium particles via transgranular type of fracture with the accumulation of twins near the fracture surface of magnesium. Mechanical properties of the composites were observed to be comparable to that of bone and the composites exhibited biodegradable and bioinert character upon testing in Ringer's solution such that magnesium was selectively corroded and pores were formed at prior magnesium powder sites while titanium preserved its starting skeleton structure. In addition, it was found that volume ratio of titanium and magnesium, and continuous MgO layer are the most important parameters which should be considered in designing biodegradable magnesium alloys with an appropriate corrosion rate. (C) 2013 Elsevier B.V. All rights reserved.
Citation Count: Guler, I.; Gasanly, N. M., "Compositional Dependence of Raman-Active Mode Frequencies and Line Widths in Tlıns2xse2(1-X) Mixed Crystals", Applied Surface Science, 318, pp. 113-115, (2014).
Compositional Dependence of Raman-Active Mode Frequencies and Line Widths in Tlıns2xse2(1-X) Mixed Crystals
(Elsevier Science, 2014) Güler, I.; Gasanly, N. M.; Korkmaz, F.
The Raman spectra of mixed crystals TlInS2xSe2(1-x) have been investigated in the composition range of 0.25 <= x <= 0.75 and in the high-frequency region of 250-350 cm(-1) at room temperature. It was observed that Raman-active mode frequencies decrease as the selenium atoms content increases in the mixed crystals. The effect of crystal disorder on the line broadening of three high-frequency modes is reported. (C) 2014 Elsevier B.V. All rights reserved.
Citation Count: Buke, Goknur C., "Epitaxial Graphene and Carbon Nanotubes on Silicon Carbide", Carbon Nanomaterials, 2nd Edition, pp. 115-133, (2014).
Epitaxial Graphene and Carbon Nanotubes on Silicon Carbide
(CRC Press-Taylor & Francis Group, 2014) Buke, Göknur Cambaz
Citation Count: Karataş, Mustafa Serdar...et al. "A Comparison of Radiation Shielding of Stainless Steel With Different Magnetic Properties", Nuclear Technology and Radiation Protection, Vol. 29, No. 3, pp. 186-189, (2014).
A Comparison of Radiation Shielding of Stainless Steel With Different Magnetic Properties
(Vinca Inst Nuclear Sci, 2014) Çalık, Adnan; Akbunar, Şahin; Uçar, Nazim; Yılmaz, Nihat; Karakaş, Mustafa Serdar; Akkurt, İskender; 48915
The radiation shielding properties of three different stainless steels have been investigated. For this purpose, linear attenuation coefficients at photon energy levels of 662 keV and 1250 keV have been mea sured. The obtained results showed that ferritic stainless steel was more capable in stopping the high energy photons than its non-magnetic counterpart. © 2014 Vinca Inst Nuclear Sci. All rights reserved.
Citation Count: Kalay, Ilkay; Kramer, Matthew J.; Napolitano, RE., "Crystallization kinetics and phase transformation mechanisms incu56zr44 glassy alloy" Metallurgical And Materials Transactions A-Physical Metallurgy And Materials Science, Vol.46A, No.6, pp.3356-3364, (2015).
Crystallization kinetics and phase transformation mechanisms incu56zr44 glassy alloy
(Springer, 2015) Kalay, İlkay; Kramer, Matthew J.; Napolitano, R. E.; 101579
The kinetics and phase selection mechanisms involved in the crystallization of an amorphous Cu-Zr alloy of eutectic composition (Cu56Zr44) were investigated using in situ high-energy X-ray diffraction (HEXRD), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC) under isothermal and constant heating rate conditions. In situ HEXRD results for 10 K/min (10 A degrees C/min) heating indicate that the amorphous alloy devitrifies into CuZr2 and mainly Cu10Zr7 at the crystallization temperature of 725 K (452 A degrees C). The sequence continues with the precipitation of CuZr (B2) at 1004 K (731 A degrees C), where these three phases coexist until the decomposition of CuZr2 is observed at 1030 K (757 A degrees C). The two equilibrium phases Cu10Zr7 and CuZr (B2) remain present on further heating until melting at the eutectic temperature for the Cu56Zr44 alloy. TEM investigation of the isothermal [705 K (432 A degrees C)] crystallization sequence reveals primary nucleation and growth of the Cu10Zr7 phase, where growth of the Cu10Zr7 crystals is initially planar with a transition to a cellular morphology, associated with partitioning of Zr at the growth front. Related cellular structures and composition profiles are quantified. (C) The Minerals, Metals & Materials Society and ASM International 2015
Citation Count: Cullinan, Tim...et.al., "Kinetics and mechanisms of isothermal devitrification inamorphous cu50zr50" Metallurgical And Materials Transactions A-Physical Metallurgy And Materials Science, Vol.46A, No.2, pp.600-613, (2015).
Kinetics and mechanisms of isothermal devitrification inamorphous cu50zr50
(Springer, 2015) Cullinan, Tim; Kalay, İlkay; Kalay, Y. Eren; Kramer, Matt; Napolitano, Ralph; 101579
The crystallization kinetics and microstructural dynamics associated with devitrifying a melt-spun Cu50Zr50 metallic glass were investigated using isothermal treatments, in situ high-energy synchrotron X-ray diffraction, conventional and high-resolution transmission electron microscopy, and differential scanning calorimetry. The analysis of isothermal transformations allows us to more clearly unravel the complex interplay between nucleation and growth of competing stable and metastable phases. The isothermal devitrification response was found to involve the Cu10Zr7, CuZr2, and CuZr phases, consistent with previously reported constant heating rate experiments, but here we have resolved the phase evolution and structural characteristics of the transformation, including the very early stages of crystallization. At 671 K (398 A degrees C), the isothermal transformation starts with the formation of the Cu10Zr7 phase, which grows in a generally equiaxed morphology. At a size of approximately 100 nm, the growth of the Cu10Zr7 particles is interrupted by the precipitation of a thin layer of the CuZr2 phase, upon which the metastable CuZr (B2) grows epitaxially. Crystallization kinetics are quantified here though in situ measurements (HEXRD, DSC) and ex situ microstructural analysis (TEM, HRTEM). Finally, the influences of chemical partitioning, diffusion, and crystallographic orientation on this sequence are examined.
Corrosion of Metallic Biomaterials
(Springer Verlag, 2015) Dikici, Burak; Esen, Ziya; Duygulu, Özgür; Güngör, Serap; 52373
Metallic materials have been used as biomedical implants for various parts of the human body for many decades. The physiological environment (body fluid) is considered to be extremely corrosive to metallic surfaces; and corrosion is one of the major problems to the widespread use of the metals in the human body since the corrosion products can cause infections, local pain, swelling, and loosening of the implants. Recently, the most common corrosion-resistant metallic biomaterials are made of stainless steels and titanium and its alloys along with cobalt chromium molybdenum alloys. It is well known that protective surface films of the alloys play a key role in corrosion of the metallic implants. Key documents on the corrosion behavior of the metallic biomaterials in human body have been compiled under this chapter as a review.
Citation Count: Kiraci, Ali; Yurtseven, F.; Korkmaz, C. Sisman, "Temperature Dependence of the Brillouin Frequency Shift and the Linewidth of the LA Mode in the Ferroelectric Phase of PZT-x (PbZr1-xTixO3)", Joint IEEE International Symposium on the Applications of Ferroelectric / International Symposium on Integrated Functionalities / Piezoelectric Force Microscopy Workshop (ISAF/ISIF/PFM), pp. 1-4, (2015).
Temperature Dependence of the Brillouin Frequency Shift and the Linewidth of the LA Mode in the Ferroelectric Phase of PZT-x (PbZr1-xTixO3)
(IEEE, 2015) Yurtseven, F.; Korkmaz, C. Şişman; 42475
The temperature dependence of the Brillouin frequency and the linewidth of the LA mode is studied for the concentration of x=0.45 in the ferroelectric phase of PbZr1-xTixO3 (PZT-x) within the temperature range of 443 to 656 K (T-C=657 K). Using the experimental data for the Brillouin frequency of the LA mode as an order parameter below T-C the temperature dependence of the linewidth (FWHM) is calculated by the pseudospin-phonon coupled model and the energy fluctuation model for the lead titanate zirconate (x=0.45). Additionally, the activation energies are compared from the damping constant (linewidth) using both models for the temperature range of 443 to 656 K in the ferroelectric phase of PbZr1-xTixO3. Our calculated values for the damping constant are in agreement with the observed data for the ferroelectric phase of PbZr1-xTixO3 single crystals. The activation energies calculated from both models are much higher in the ferroelectric phase than the value of k(B)T(C)=0.056 eV at the transition temperature for PbZr1-xTixO3 (x=0.45).
Citation Count: Cullinan, Tim...et al. (2015). "Kinetics and Mechanisms of Isothermal Devitrification in Amorphous Cu50Zr50", Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, Vol. 46, No. 2, pp. 600-613.
Kinetics and Mechanisms of Isothermal Devitrification in Amorphous Cu50Zr50
(2015) Cullinan, Tim; Kalay, İlkay; Kalay, Y. Eren; Kramer, Matt; Napolitano, Ralph; 101579
The crystallization kinetics and microstructural dynamics associated with devitrifying a meltspun Cu50Zr50 metallic glass were investigated using isothermal treatments, in situ high-energy synchrotron X-ray diffraction, conventional and high-resolution transmission electron microscopy, and differential scanning calorimetry. The analysis of isothermal transformations allows us to more clearly unravel the complex interplay between nucleation and growth of competing stable and metastable phases. The isothermal devitrification response was found to involve the Cu10Zr7, CuZr2, and CuZr phases, consistent with previously reported constant heating rate experiments, but here we have resolved the phase evolution and structural characteristics of the transformation,including the very early stages of crystallization. At 671 K (398C),the isothermal transformation starts with the formation of the Cu10Zr7 phase, which grows in a generally equiaxed morphology. At a size of approximately 100 nm, the growth of the Cu10Zr7 particles is interrupted by the precipitation of a thin layer of the CuZr2 phase, upon which the metastable CuZr (B2) grows epitaxially. Crystallization kinetics are quantified here though in situ measurements (HEXRD, DSC) and ex situ microstructural analysis (TEM, HRTEM). Finally, the influences of chemical partitioning, diffusion, and crystallographic orientation on this sequence are examined. © 2014, The Minerals, Metals & Materials Society and ASM International.
Citation Count: Butev, Ezgi; Esen, Ziya; Bor, Sakir, "In Vitro Bioactivity Investigation of Alkali Treated Ti6al7nb Alloy Foams", Applied Surface Science, 327, pp. 437-443, (2015).
In Vitro Bioactivity Investigation of Alkali Treated Ti6al7nb Alloy Foams
(Elsevier, 2015) Bütev, Ezgi; Esen, Ziya; Bor, Şakir; 47423
Biocompatible Ti6Al7Nb alloy foams with 70% porosity manufactured by space holder method were activated via alkali treatment using 5 M NaOH solution at 60 degrees C. The interconnected pore structures enabled formation of homogenous sodium rich coating on the foam surfaces by allowing penetration of alkali solution throughout the pores which had average size of 200 mu m. The resulted coating layer having 500 nm thickness exhibited porous network morphology with 100 nm pore size. On the other hand, heat treatment conducted subsequent to alkali treatment at 600 degrees C in air transformed sodium rich coating into crystalline bioactive sodium titanate phases. Although the coatings obtained by additional heat treatment were mechanically stable and preserved their morphology, oxidation of the samples deteriorated the compressive strength significantly without affecting the elastic modulus. However, heat treated samples revealed better hydroxyapatite formation when soaked in simulated body fluid (SBF) compared to alkali treated foams. On the other hand, untreated surfaces containing bioactive TiO2 layer were observed to comprise of Ca and P rich precipitates only rather than hydroxyapatite within 15 days. The apatite formed on the treated porous surfaces was observed to have flower-like structure with Ca/P ratio around 1.5 close to that of natural bone. (C) 2014 Elsevier B.V. All rights reserved.
Citation Count: Bilgin, Güney Mert...et al. "Microstructural Refinement of Ti-6Al-4V Alloy Fabricated by Additive Manufacturing Using Thermochemical Processes", 18th International Metallurgy & Materials Congress, İstanbul, Türkiye, (29 Eylül - 01 Ekim 2016).
Microstructural Refinement of Ti-6Al-4V Alloy Fabricated by Additive Manufacturing Using Thermochemical Processes
(2016) Bilgin, Güney Mert; Esen, Ziya; Kuşhan Akın, Şeniz Reyhan; Dericioğlu, Arcan Fehmi; 52373; 224219

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