Mechanical properties and cytotoxic evaluation of the Ti-3Nb-13Zr alloy

Ti-13Nb-13Zr is a new titanium alloy that was originally developed for medical implant applications. This alloy combines a low elastic modulus, high strength, excellent hot and cold workability, and superior corrosion resistance. Research on this alloy has shown that the mechanical properties can be controlled over a significant range through hot working, heat treatment and cold-working. The present study describes the mechanical properties and cytotoxic evaluation of the Ti-13Nb-13Zr alloy, which was produced by furnace arc melting in argon atmosphere. The elemental constituents were unalloyed Ti, Nb and Zr sheets. The obtained ingots, which initial diameter were about 15 mm, have undergone sequences of cold-working and heat treatments in order to achieve a final diameter of 6 mm. The tensile strength of Ti-13Nb-13Zr achieved 1270 MPa (cold-worked – 60% reduction in area) and 860 MPa after heat treatment (60% reduction in area + 1000 o C/1h + water quenched). The elastic module were 52 GPa and 60 GPa respectively. Furthermore, the toxic effect of this alloy on cells was evaluated by a cytotoxicity test, a quantitative method of colony suppression assay using Chinese Hamster Ovary (CHO) cultured cells in contact with diluted extracts of the biomaterials. The results showed that Ti-13Nb-13Zr alloy obtained by furnace arc melting isn’t cytotoxic.Peer Reviewe

Development of the microstructure of the silicon nitride based ceramics

Basic regularities of silicon nitride based materials microstructure formation and development in interrelation with processing conditions, type of sintering additives, and starting powders properties are discussed. Models of abnormal or exaggerated grain growth are critically reassessed. Results of several model experiments conducted in order to determine the most important factors directing the microstructure formation processes in RE-fluxed Si3N4 ceramics are reviewed. Existing data on the mechanisms governing the microstructure development of Si3N4-based ceramics are analyzed and several principles of microstructure tailoring are formulated

Mixture Design And Response Surface Analysis Of Densification Of Silicon Carbide Ceramics With (sio2-dy2o3-al 2o3) Additives

Statistical mixture designs are used to systematically study the densification properties of silicon carbide (SiC) ceramics sintered with SiO2, Dy2O3, and Al2O3. Mixture models for percentage theoretical density and SiC weight loss as a function of the SiO2, Dy2O3, and Al 2O3 oxide proportions have been determined and validated by analysis of variance. The results indicate a region confined by about 0-20 mol% silica, 50-65 mol% dysprosia, and 40-65 mol% alumina, with all samples containing 10% by volume of additives, and simultaneously maximization of density values and minimization of weight loss during SiC-based ceramic sintering. © 2009 The American Ceramic Society.74493501Yamada, K., Mohri, M., Properties and Applications of Silicon Carbide Ceramics Silicon Carbide Ceramics Vol. 1: Fundamental and Solid Reaction, , eds. S. Somiya. Y. Inomata. Elsevier Applied SciencePanpuch, R., Stuijts Memorial Lecture 1997: Ceramic Science and Technology Facing Changing Paradigms (1998) J. Eur. Ceram. Soc., 18, pp. 993-1000Negita, K., Effective Sintering Aids for Silicon Carbide Ceramics: Reactivities of Silicon Carbide with Various Additives (1986) J. Am. Ceram. Soc., 69, pp. 308-c310Rifskijk, W.V., Shanefield, D.J., Effects of Carbon as a Sintering Aid in Silicon Carbide (1990) J. Am. Ceram. Soc., 73, pp. 148-149Prochazka, S., The Role of Boron and Carbon in the Sintering of Silicon Carbide (1975) Br. Ceram. Res., pp. 171-181. , Special Ceramics 6Keppeler, M., Reichert, H.G., Broadley, J.M., Thurn, G., Wiedmann, I., Aldinger, F.J., High Temperature Mechanical Behavior of Liquid Phase Sintered Silicon Carbide (1998) J. Eur. Ceram. Soc., 18, pp. 521-526Pan, Y., Baptista, J.L., Low-Temperature Sintering of Silicon Carbide with Li2O-Al 2O3-SiO2 Melts as Sintering Aids (1996) J. Eur. Ceram. Soc., 16, pp. 1221-1230Dijen, F.K.V., Mayer, E., Liquid Phase Sintering of Silicon Carbide (1996) J. Eur. Ceram. Soc., 16, pp. 413-420Grande, T., Sommerset, H., Hagen, E., Wiik, K., Einarsrud, M.A., Effect of Weight Loss on Liquid-Phase Sintered Silicon Carbide (1997) J. Am. Ceram. Soc., 80, pp. 1047-1052Izhevskyi, V.A., Bressiani, A.H.A., Bressiani, J.C., Effect of Liquid Phase Sintering on Microstructure and Mechanical Properties of Yb2O3-AlN containing SiC-Based Ceramics (2005) J. Am. Ceram. Soc., 88, pp. 1115-1121Lee, J.K., Tanaka, H., Kim, H., Kim, D.J., Microstructural Changes in Liquid-Phase Sintered α-Silicon Carbide (1996) Mater. Lett., 29, pp. 135-142Omori, M., Takei, H., Preparation of Pressureless-Sintered SiC-Y2O 3-Al2O3 (1988) J. Mater. Sci., 23, pp. 3744-3749Mulla, M.A., Krstic, V.D., Low Temperature Pressureless Sintering of β-Silicon Carbide with Aluminium Oxide and Yttrium Oxide Additions (1991) Ceram. Bull., 70, pp. 439-443Wiley, F.L., Silicon Nitride and Related Materials (2000) J. Am. Ceram. Soc., 83, pp. 245-265Petzow, G., Hermann, M., Silicon Nitride Ceramics High Performance Non-Oxide Ceramics II. Structure and Bonding, 102. , eds. M. Jansen. F. Aldinger. D. M. P. Mingos. R. Haubner. SpringerShelby, J.E., Rare Earth as Major Components in Oxide Glasses (1994) Key Eng. Mater., 9495, pp. 81-208Shelby, J.E., Kohli, J.T., Rare-Earth Aluminosilicate Glasses (1990) J. Am. Ceram. Soc., 73, pp. 39-42Sun, W.Y., Tu, H.Y., Wang, P.L., Yan, D.S., Nitrogen-Rich Liquid Phase Regions in the Ln-Si-Al-O-N (Ln=Nd, Sm, Gd, Dy, Er and Yb) Systems (1997) J. Eur. Ceram. Soc., 17, pp. 789-796Berroth, K., Prescher, T., Development and Industrial Application of Silicon Nitride Based Ceramics (2005) Key Eng. Mater., 287, pp. 3-9Becher, P.F., Painter, G.S., Shibata, N., Satet, R.L., Hoffmann, M.J., Pennycook, S.J., Influence of Additives on Anisotropic Grain Growth in Silicon Nitride Ceramics (2006) Mater. Sci. Eng. A, 422, pp. 85-91Satet, R.L., Hoffmann, M.J., Grain Growth Anisotropy of Beta-Silicon Nitride in Rare-Earth Doped Oxynitride Glasses (2004) J. Eur. Ceram. Soc., 24, pp. 3437-3445Schneider, S.J., Engineering Materials Handbook. Ceramics and Glasses, 4. , ASM InternationalBruns, R.E., Scarminio, I.S., De Barros Neto, B., Statiastical Design - Chemometrics, , ElsevierCochran, W.G., Cox, G.M., Experimental Design, , WileyKhuri, A.I., Cornell, J.A., Response Surface. Design and Analysis, , John Wiley & SonsMarchi, J., Bressiani, J.C., Bressiani, A.H.A., Experimental Design Applied to Silicon Carbide Sintering (2003) J. Am. Ceram. Soc., 86, pp. 1208-1210Correia, S.L., Hotza, D., Segadães, A.M., Simultaneous Optimization of Linear Firing Shrinkage and Water Absorption of Triaxial Ceramic Bodies Using Experiments Design (2004) Ceram. Int., 30, pp. 917-922Nardi, J.V., Acchar, W., Hotza, D., Enhancing the Properties of Ceramic Products Through Mixture Design and Response Surface Analysis (2004) J. Eur. Ceram. Soc., 24, pp. 375-379Zárate, J., Juárez, H., Contreras, M.E., Pérez, R., Experimental Design and Results from the Preparation of Precursory Powders of ZrO2(3%Y2O3)/(10-95)% Al 2O3 Composite (2005) Powder Technol., 159, pp. 135-141Chiang, Y.M., Birnie III, D.P., Kingery, W.D., Physical Ceramics, , Wiley(2004), Statsoft Inc. Statistica (data analysis software system, version 6)De Barros Neto, B., Scarminio, I.S., Bruns, R.E., Planejamento e Otimização de Experiments, , Editora da UnicampTanabe, S., Hirao, K., Soga, N., Elastic Properties and Molar Volume of Rare-Earth Aluminosilicate Glasses (1992) J. Am. Ceram. Soc., 75, pp. 503-509Becher, P.F., Sun, E.Y., Hsueh, C.H., Alexander, K.B., Hwang, S.L., Waters, S.B., Westmouland, C.G., Debonding of Interfaces between Beta-Silicon Nitride Whiskers and Si Al y Oxynitride Glasses (1996) Acta Mater., 44, p. 388

Ceramic Composites Derived From Polysiloxane/al/nb By Afcop Process

In this work, ceramic matrix composites (CMC) were prepared by AFCOP process, using a polysiloxane network filled with metallic niobium and aluminum powders as active fillers. The liquid polysiloxane precursor was loaded with a suitable polymer/filler ratio in relation to stoichiometric Nb: C and Al: O molar ratios. Changing Al for α-Al2O3, which acted as an inert filler, non-stoichiometric conditions were obtained. The mixtures were blended, uniaxially warm pressed, and pyrolysed in flowing argon at 800, 1000 and 1200°C Thermogravimetry was used to follow the weight changes during the pyrolysis process. X-ray diffraction was used to identify the formation of new crystalline phases, such as Al2O3, NbC, Nb2C and Al3Nb in the composites. Sintered specimens were also characterized by SEM and EDS. The results indicated good potential for this system to obtain multiphasic composite material in the Al-Nb system at lower temperatures.498-499375380Greil, P., (2000) Adv. Eng. Mater, 2, p. 339Wei, Q., Pippel, E., Woltersdorf, J., Scheffler, M., Greil, P., (2002) Mater. Chem. and Phys, 73, p. 281Greil, P., (1995) J. Am. Ceram. Soc, 78, p. 835Schiavon, M.A., Radovanovic, E., Yoshida, I.V.P., (2002) Powder Technol, 123, p. 232Dernovsek, O., Bressiani, J.C., Bressiani, A.H.A., Aechar, W., Greil, P., (2000) J. Mater. Sci, 35, p. 2201Schiavon, M.A., Pardini, L.C., Yoshida, I.V.P., (2001) Key Eng. Mater, 189, p. 48Schiavon, M.A., Redondo, S.A.U., Pina, S.R.O., Yoshida, I.V.P., (2002) J. Non-Cryst. Solids, 304, p. 92. , 10Powder Diffraction File Search Manual, Joint Committee on Powder Diffraction Standarts, Swarthmore, (1973)Michalet, T., Parlier, M., Beclin, F., Duelos, R., Crampon, J., (2002) J. Eur. Ceram. Soc, 22, p. 14

Mechanical properties and cytotoxic evaluation of the Ti-3Nb-13Zr alloy

Ti-13Nb-13Zr is a new titanium alloy that was originally developed for medical implant applications. This alloy combines a low elastic modulus, high strength, excellent hot and cold workability, and superior corrosion resistance. Research on this alloy has shown that the mechanical properties can be controlled over a significant range through hot working, heat treatment and cold-working. The present study describes the mechanical properties and cytotoxic evaluation of the Ti-13Nb-13Zr alloy, which was produced by furnace arc melting in argon atmosphere. The elemental constituents were unalloyed Ti, Nb and Zr sheets. The obtained ingots, which initial diameter were about 15 mm, have undergone sequences of cold-working and heat treatments in order to achieve a final diameter of 6 mm. The tensile strength of Ti-13Nb-13Zr achieved 1270 MPa (cold-worked – 60% reduction in area) and 860 MPa after heat treatment (60% reduction in area + 1000 o C/1h + water quenched). The elastic module were 52 GPa and 60 GPa respectively. Furthermore, the toxic effect of this alloy on cells was evaluated by a cytotoxicity test, a quantitative method of colony suppression assay using Chinese Hamster Ovary (CHO) cultured cells in contact with diluted extracts of the biomaterials. The results showed that Ti-13Nb-13Zr alloy obtained by furnace arc melting isn’t cytotoxic.Peer Reviewe

Liquid phase sintered SiC. Processing and transformation controlled microstructure tailoring

Microstructure development and phase formation processes during sintering of silicon carbide based materials with AlN-Y2O3, AlN-Yb2O3, and AlN-La2O3 sintering additives were investigated. Densification of the materials occurred by liquid-phase sintering mechanism. Proportion of alpha- and beta-SiC powders in the initial mixtures was a variable parameter, while the molar ratio of AlN/RE2O3, and the total amount of additives (10 vol. %) were kept constant. Shrinkage behavior during sintering in interrelation with the starting composition of the material and the sintering atmosphere was investigated by high temperature dilatometry. Kinetics of b-SiC to a-SiC phase transformation during post-sintering heat treatment at temperatures 1900-1950 °C was studied, the degree of phase transformation being determined by quantitative x-ray analysis using internal standard technique. Evolution of microstructure resulting from beta-SiC to alpha-SiC transformation was followed up by scanning electron microscopy on polished and chemically etched samples. Transformation-controlled grain growth mechanism similar to the one observed for silicon nitride based ceramics was established. Possibility of in-situ platelet reinforced dense SiC-based ceramics fabrication with improved mechanical properties by means of sintering was shown

Densification studies of silicon carbide-based ceramics with yttria, silica and alumina as sintering additives

Silicon carbide has been extensively used in structural applications, especially at high temperatures. In this work, Y2O3, Al2O3 and SiO2 were added to beta-SiC in order to obtain highly dense ceramics. Sintering was conducted in a dilatometer and in a graphite resistance furnace and the densification behaviour was studied. Sintered samples were characterised by density measurements, the crystalline phases were identified by X-ray diffraction. Microstructural observation of polished and polished/etched samples was carried out with help of scanning electron microscopy. Silicon carbide ceramics with more than 90% of the theoretical density were obtained by pressureless sintering if a suitable proportion of the additives is used