Sample records for hardened beta titanium

  1. Phase transformations in titanium alloys hardened by rapid heating

    Gridnev, V.N.; Ivasishin, O.M.; Oshkaderov, S.P.; Smirnov, A.M. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)

    Features of phase transformations in titanium alloys, which subjected to hardening by rapid heating, are studied. The model for mathematical description of ..cap alpha..+..beta.. ..-->.. ..beta..- transformation under the conditions of continuous heating with different rate, is proposed. The increase of the polymorphic transformation temperature with the heating rate, is predicted and confirmed experimentally. Under certain conditions this fact can result in a two-stage process, of ..cap alpha..+..beta.. ..-->.. ..beta..-transformation, which begins according to difussion mechanism, and completes according to the non-diffusion one. It is shown, that ..cap alpha..+..beta.. ..-->.. ..beta..-transformation under non-equilibrium conditions is followed by appearing of concentration non-uniformity in reacting phases, that essentially affects the grain and intragranular structure of hardened alloys, and their phase composition. Variants of phase composition of the alloys of different classes quenched after rapid heating in the ..beta..-field, are analyzed. Possible aspects of the effect of increased heating rates on the ageing process are considered.

  2. An Oxygen-Permeation Treatment for Hardening Titanium Alloys

    MA Hong-yan; WANG Mao-cai; WEI Zheng; XIN Gong-chun


    In this paper, the characterization of oxygen permeation (OP) in titanium alloy TC11 at high temperature and the influence of oxygen solution layer on performances of substrate were characterized with the help of apparatus, such as TGA,SEM/EDAX, XRD, EPMA, Micro-hardness Tester, Two-body Abrasion Tester, Amsler Wear Test Machine, Potentiostat/Galvanostat Model 273 system. The results showed that there was a little shift in X-ray diffraction peaks of α and β phase during the OPT process as a result of oxygen solution. The OP treatment can significantly increase the surface hardness of titanium alloys and, accordingly, the abrasive wear resistance was improved. Titanium alloys with oxygen solution layer exhibited improved corrosion resistance both in 3.5 % NaCl and in 5 % HCl solution. Oxidation resistance of TC11 with oxygen solution layer at high temperature was also enhanced. The solution and hardening mechanisms were discussed based on the experimental results.

  3. Influence of. beta. -phase unhomogeneity on titanium martensite structure

    Gridnev, V.N.; Ivasishin, O.M.; Markovskij, P.E.; Oshkaderov, S.P.; Svechnikov, V.L. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)

    Martensite structure is studied, formed by the hardening of unhomogeneous ..beta..-solid solution, its concentration unhomogeneity being formed under accelerated heating while hardening. It is established that changes in morphology and crystal geometry of martensite are observed with hardening temperature increasing. The concentration unhomogeneity of ..beta..-phase may lead to the simultaneous existence of various types of martensite together with the increased quantity of the residual ..beta..-phase.

  4. Hardening of the surface layers of commercial pure titanium VT1-0 under combined treatment

    Bashchenko, Lyudmila P.; Gromov, Viktor E.; Budovskikh, Evgenii A.; Ivanov, Yurii F.; Soskova, Nina A.


    The treatment of VT1-0 titanium samples was carried out by concentrated energy fluxes. The combined treatment included surface carburizing with the joint use of powder samples of compounds with high physical and mechanical properties (namely, titanium diboride TiB2, silicon carbide SiC and zirconium oxide ZrO2) and subsequent electron beam treatment of surface layers formed in electroexplosive treatment. The combined treatment of surface layers resulted in the multifold increase in microhardness, which reduces depending on the depth of hardening zone. After electron-beam treatment, the depth of hardening zone is increased. During electron-beam treatment, the two-layer hardening zone forms.

  5. Hardening of the surface layers of commercial pure titanium VT1-0 under combined treatment

    Bashchenko, Lyudmila P., E-mail:; Gromov, Viktor E., E-mail:; Budovskikh, Evgenii A., E-mail:; Soskova, Nina A., E-mail: [Siberian State Industrial University, Novokuznetsk, 654007 (Russian Federation); Ivanov, Yurii F., E-mail: [Institute of High Current Electronics SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation)


    The treatment of VT1-0 titanium samples was carried out by concentrated energy fluxes. The combined treatment included surface carburizing with the joint use of powder samples of compounds with high physical and mechanical properties (namely, titanium diboride TiB{sub 2}, silicon carbide SiC and zirconium oxide ZrO{sub 2}) and subsequent electron beam treatment of surface layers formed in electroexplosive treatment. The combined treatment of surface layers resulted in the multifold increase in microhardness, which reduces depending on the depth of hardening zone. After electron-beam treatment, the depth of hardening zone is increased. During electron-beam treatment, the two-layer hardening zone forms.

  6. Devising Strain Hardening Models Using Kocks–Mecking Plots—A Comparison of Model Development for Titanium Aluminides and Case Hardening Steel

    Markus Bambach


    Full Text Available The present study focuses on the development of strain hardening models taking into account the peculiarities of titanium aluminides. In comparison to steels, whose behavior has been studied extensively in the past, titanium aluminides possess a much larger initial work hardening rate, a sharp peak stress and pronounced softening. The work hardening behavior of a TNB-V4 (Ti–44.5Al–6.25Nb–0.8Mo–0.1B alloy is studied using isothermal hot compression tests conducted on a Gleeble 3500 simulator, and compared to the typical case hardening steel 25MoCrS4. The behavior is analyzed with the help of the Kocks-Mecking plots. In contrast to steel the TNB-V4 alloy shows a non-linear course of θ (i.e., no stage-III hardening initially and exhibits neither a plateau (stage IV hardening nor an inflection point at all deformation conditions. The present paper describes the development and application of a methodology for the design of strain hardening models for the TNB-V4 alloy and the 25CrMoS4 steel by taking the course of the Kocks-Mecking plots into account. Both models use different approaches for the hardening and softening mechanisms and accurately predict the flow stress over a wide range of deformation conditions. The methodology may hence assist in further developments of more sophisticated physically-based strain hardening models for TiAl-alloys.

  7. Implantation induced hardening of nanocrystalline titanium thin films.

    Krishnan, R; Amirthapandian, S; Mangamma, G; Ramaseshan, R; Dash, S; Tyagi, A K; Jayaram, V; Raj, Baldev


    Formation of nanocrystalline TiN at low temperatures was demonstrated by combining Pulsed Laser Deposition (PLD) and ion implantation techniques. The Ti films of nominal thickness approximatly 250 nm were deposited at a substrate temperature of 200 degrees C by ablating a high pure titanium target in UHV conditions using a nanosecond pulsed Nd:YAG laser operating at 1064 nm. These films were implanted with 100 keV N+ ions with fluence ranging from 1.0 x 10(16) ions/cm2 to 1.0 x 10(17) ions/cm2 The structural, compositional and morphological evolutions were tracked using Transmission Electron Microscopy (TEM), Secondary Ion Mass Spectrometry (SIMS) and Atomic Force Microscopy (AFM), respectively. TEM analysis revealed that the as-deposited titanium film is an fcc phase. With increasing ion fluence, its structure becomes amorphous phase before precipitation of nanocrystalline fcc TIN phase. Compositional depth profiles obtained from SIMS have shown the extent of nitrogen concentration gradient in the implantation zone. Both as-deposited and ion implanted films showed much higher hardness as compared to the bulk titanium. AFM studies revealed a gradual increase in surface roughness leading to surface patterning with increase in ion fluence.

  8. Biocompatibility of beta-stabilizing elements of titanium alloys.

    Eisenbarth, E; Velten, D; Müller, M; Thull, R; Breme, J


    In comparison to the presently used alpha + beta titanium alloys for biomedical applications, beta-titanium alloys have many advantageous mechanical properties, such as an improved wear resistance, a high elasticity and an excellent cold and hot formability. This will promote their future increased application as materials for orthopaedic joint replacements. Not all elements with beta-stabilizing properties in titanium alloys are suitable for biomaterial applications-corrosion and wear processes cause a release of these alloying elements to the surrounding tissue. In this investigation, the biocompability of alloying elements for beta- and near beta-titanium alloys was tested in order to estimate their suitability for biomaterial components. Titanium (grade 2) and the implant steel X2CrNiMo18153 (AISI 316 L) were tested as reference materials. The investigation included the corrosion properties of the elements, proliferation, mitochondrial activity, cell morphology and the size of MC3T3-E1 cells and GM7373 cells after 7 days incubation in direct contact with polished slices of the metals. The statistical significance was considered by Weir-test and Lord-test (alpha = 0.05). The biocompatibility range of the investigated metals is (decreasing biocompatibility): niobium-tantalum, titanium, zirconium-aluminium-316 L-molybdenum.

  9. Corrosion wear fracture of new {beta} biomedical titanium alloys

    Niinomi, M.; Fukunaga, K.-I. [Toyohashi Univ. of Technol. (Japan). Dept. of Production Syst. Eng.; Kuroda, D.; Morinaga, M.; Kato, Y.; Yashiro, T.; Suzuki, A.


    Metallic materials such as stainless steel, Co-Cr alloy, pure titanium and titanium alloys have been used for surgical implant materials. The {alpha} + {beta} type titanium alloy such as Ti-6Al-4V ELI has been most widely used as an implant material for artificial hip joint and dental implant because of its high strength and excellent corrosion resistance. Toxicity of alloying elements in conventional biomedical titanium alloys like Al and V, and the high modulus of elasticity of these alloy as compared to that of bone have been, however, pointed out [1,2]. New {beta} type titanium alloys composed of non-toxic elements like Nb, Ta, Zr, Mo and Sn with lower moduli of elasticity, greater strength and greater corrosion resistance were, therefore, designed in this study. The friction wear properties of titanium alloys are, however, low as compared to those of other conventional metallic implant materials such as stainless steels and Co-Cr alloy. Tensile tests and friction wear tests in Ringer`s solution were conducted in order to investigate the mechanical properties of designed alloys. The friction wear characteristics of designed alloys and typical conventional biomedical titanium alloys were evaluated using a pin-on-disk type friction wear testing system and measuring the weight loss and width of groove of the specimen. (orig.) 8 refs.

  10. Low-Temperature Forming of Beta Titanium Alloys

    Kaneko, R. S.; Woods, C. A.


    Low cost methods for titanium structural fabrication using advanced cold-formable beta alloys were investigated for application in a Mach 2.7 supersonic cruise vehicle. This work focuses on improving processing and structural efficiencies as compared with standard hot formed and riveted construction of alpha-beta alloy sheet structure. Mechanical property data and manufacturing parameters were developed for cold forming, brazing, welding, and processing Ti-15V-3Cr-3Sn-3Al sheet, and Ti-3Al-8V-6Cr-4Zr on a more limited basis. Cost and structural benefits were assessed through the fabrication and evaluation of large structural panels. The feasibility of increasing structural efficiency of beta titanium structure by selective reinforcement with metal matrix composite was also explored.

  11. Optimal welding of beta titanium orthodontic wires.

    Nelson, K R; Burstone, C J; Goldberg, A J


    Today the orthodontist is confronted by an array of new orthodontic wire materials that, when applied to appliance design, can vastly increase the flexibility and versatility of therapy. Welded joints, especially for the newer titanium alloy wires, provide a means to extend the useful applications of these materials. The purpose of this study was to determine the optimum settings for electrical resistance welding of various configurations of titanium-molybdenum (TMA) wires. Specimens were of a t-joint configuration and were mechanically tested in torsion to simulate the failure mode most often observed in clinical practice. Variables included wire size, wire orientation, and welding voltage. Results indicated that excellent welds can be obtained with very little loss of strength and ductility in the area of the weld joint. Torsional loads at failure were at least 90% of the unwelded base material. Although a wide range of voltage settings resulted in high-strength welds, typically a narrow range of voltages yielded optimal ductility.

  12. Hydrogen trapping in aged {beta}-titanium alloys

    Pound, B.G. [SRI International, Menlo Park, CA (United States). Materials Research Center


    Hydrogen trapping in three {beta}-titanium alloys (unaged and aged Ti-15V-3Cr-3Al-3Sn and Beta-21S, and partially aged Beta-C) was investigated using a potentiostatic pulse technique. The apparent trapping constant ({kappa}{sub a}) and hydrogen entry flux were determined for each alloy in 1 mol l{sup {minus}1} acetic acid/1 mol l{sup {minus}1} sodium acetate. The results were compared with those for other {beta}-Ti alloys (Ti-10V-2Fe-3Al, Ti-13V-11Cr-3Al and fully aged Beta-C) studied previously. Aging caused a negligible change in {kappa}{sub a} for Ti-15-3, whereas a marked increase was observed for Beta-21S and the other {beta}-Ti alloys. Among the aged alloys, Ti-13-11-3 had the highest value of {kappa}{sub a} and Ti-15-3 had the lowest value. The intrinsic susceptibilities of Beta-C and Beta-21S to hydrogen embrittlement (HE), as represented by the trapping constants, were comparable and significantly higher than that of Ti-15-3. The susceptibilities were consistent with the relative resistances to HE observed for these alloys.

  13. Measurement and material modeling of biaxial work-hardening behavior for pure titanium sheet

    Sumita, Takeshi; Kuwabara, Toshihiko


    Biaxial tensile tests of a commercial pure titanium sheet (JIS ♯1) were performed using a servo-controlled multiaxial tube expansion testing machine developed by one of the authors [Kuwabara, T. and Sugawara, F., Multiaxial tube expansion test method for measurement of sheet metal deformation behavior under biaxial tension for a large strain range, Int. J. Plasticity, 45 (2013), 103-118]. Tubular specimens with an inner diameter of 54 mm were fabricated by roller bending and TIG welding the as-received test material with a thickness of 0.5 mm. Several linear stress paths in the first quadrant of the stress space were applied to the tubular specimens to measure the contours of plastic work and the directions of the plastic strain rates for an equivalent plastic strain range of 0.05 ≤ ɛ0p ≤ 0.30. It was found that the shapes of the work contours significantly changed with an increase in ɛ0p and that the Yld2000-2d yield function could reproduce the differential work hardening behavior of the test material by changing the material parameters and the exponent as functions of ɛ0p.

  14. High strength beta titanium alloys: New design approach

    Okulov, I.V., E-mail: [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); TU Dresden, Institut für Werkstoffwissenschaft, D-01062 Dresden (Germany); Wendrock, H. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Volegov, A.S. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Institute of Natural Sciences, Ural Federal University, 620000 Ekaterinburg (Russian Federation); Attar, H. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); School of Engineering, Edith Cowan University, 270 Joondalup Drive, Joondalup, Perth, WA 6027 (Australia); Kühn, U. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Skrotzki, W. [TU Dresden, Institut für Strukturphysik, D-01062 Dresden (Germany); Eckert, J. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); TU Dresden, Institut für Werkstoffwissenschaft, D-01062 Dresden (Germany)


    A novel approach for development of high strength and ductile beta titanium alloys was proposed and successfully applied. The microstructure of the designed alloys is fully composed of a bcc β-Ti phase exhibiting dendritic morphology. The new Ti{sub 68.8}Nb{sub 13.6}Cr{sub 5.1}Co{sub 6}Al{sub 6.5} (at%) alloy (BETA{sup tough} alloy) exhibits a maximum tensile strength of 1290±50 MPa along with 21±3% of fracture strain. The specific energy absorption value upon mechanical deformation of the BETA{sup tough} alloy exceeds that of Ti-based metallic glass composites and commercial high strength Ti-based alloys. The deformation behavior of the new alloys was correlated with their microstructure by means of in-situ studies of the microstructure evolution upon tensile loading in a scanning electron microscope.

  15. Newly developed Ti-Nb-Zr-Ta-Si-Fe biomedical beta titanium alloys with increased strength and enhanced biocompatibility.

    Kopova, Ivana; Stráský, Josef; Harcuba, Petr; Landa, Michal; Janeček, Miloš; Bačákova, Lucie


    Beta titanium alloys are promising materials for load-bearing orthopaedic implants due to their excellent corrosion resistance and biocompatibility, low elastic modulus and moderate strength. Metastable beta-Ti alloys can be hardened via precipitation of the alpha phase; however, this has an adverse effect on the elastic modulus. Small amounts of Fe (0-2 wt.%) and Si (0-1 wt.%) were added to Ti-35Nb-7Zr-6Ta (TNZT) biocompatible alloy to increase its strength in beta solution treated condition. Fe and Si additions were shown to cause a significant increase in tensile strength and also in the elastic modulus (from 65 GPa to 85 GPa). However, the elastic modulus of TNZT alloy with Fe and Si additions is still much lower than that of widely used Ti-6Al-4V alloy (115 GPa), and thus closer to that of the bone (10-30 GPa). Si decreases the elongation to failure, whereas Fe increases the uniform elongation thanks to increased work hardening. Primary human osteoblasts cultivated for 21 days on TNZT with 0.5Si+2Fe (wt.%) reached a significantly higher cell population density and significantly higher collagen I production than cells cultured on the standard Ti-6Al-4V alloy. In conclusion, the Ti-35Nb-7Zr-6Ta-2Fe-0.5Si alloy proves to be the best combination of elastic modulus, strength and also biological properties, which makes it a viable candidate for use in load-bearing implants.

  16. Peculiarities of high-temperature. beta. -phase formation during rapid heating of titanium-molybdenum alloys

    Gridnev, V.N.; Zhuravlev, A.F.; Zhuravlev, B.F.; Ivasishin, O.M.; Oshkaderov, S.P. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)


    In the framework of the diffusion mechanism of ..cap alpha..+..beta.. ..-->.. ..beta.. transformation the model for calculating interface location determining the degree of transformation and concentration of the formed ..beta..-phase during continuous heating under different rates in titanium alloys with ..beta..-isomorphous alloying elements is suggested. On the example of Ti-10% Mo alloy the comparison of calculation and experimental results of determining parameters of ..cap alpha..+..beta.. ..-->.. ..beta.. transformation is performed.

  17. Microstructure and corrosion behavior of binary titanium alloys with beta-stabilizing elements.

    Takada, Y; Nakajima, H; Okuno, O; Okabe, T


    Binary titanium alloys with the beta-stabilizing elements of Co, Cr, Cu, Fe, Mn and Pd (up to 30%) and Ag (up to 45%) were examined through metallographic observation and X-ray diffractometry to determine whether beta phases that are advantageous for dental use could be retained. Corrosion behavior was also investigated electrochemically and discussed thermodynamically. Some cast alloys with Co, Cr, Fe, Mn, and Pd retained the beta phase, whereas those with Ag and Cu had no beta phase. In some alloys, an intermetallic compound formed, based on information from the phase diagram. The corrosion resistance deteriorated in the TiAg alloys because Ti2Ag and/or TiAg intermetallic compounds preferentially dissolved in 0.9% NaCl solution. On the other hand, the remaining titanium alloys became easily passive and revealed good corrosion resistance similar to pure titanium since their matrices seemed to thermodynamically form titanium oxides as did pure titanium.

  18. Enhancement of wear and corrosion resistance of beta titanium alloy by laser gas alloying with nitrogen

    Chan, Chi-Wai, E-mail: [School of Mechanical and Aerospace Engineering, Queen' s University Belfast, BT9 5AH (United Kingdom); Lee, Seunghwan [Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Smith, Graham [Department of Natural Sciences, University of Chester, Thornton Science Park, Chester CH2 4NU (United Kingdom); Sarri, Gianluca [School of Mathematics and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Ng, Chi-Ho [School of Mechanical and Aerospace Engineering, Queen' s University Belfast, BT9 5AH (United Kingdom); Laser Engineering and Manufacturing Research Centre, Faculty of Science and Engineering, University of Chester, Parkgate Road, Chester CH1 4BJ (United Kingdom); Sharba, Ahmed [School of Mathematics and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Man, Hau-Chung [Department of Industrial and Systems Engineering, Faculty of Engineering, The Hong Kong Polytechnic University, Hong Kong (China)


    Graphical abstract: - Highlights: • Laser technology is a fast, clean and flexible method for surface hardening of TNZT. • Laser can form a protective hard layer on TNZT surface without altering surface roughness. • The laser-formed layer is metallurgically bonded to the substrate. • Laser-treated TNZT is highly resistant to corrosion and wear in Hank's solution. - Abstract: The relatively high elastic modulus coupled with the presence of toxic vanadium (V) in Ti6Al4V alloy has long been a concern in orthopaedic applications. To solve the problem, a variety of non-toxic and low modulus beta-titanium (beta-Ti) alloys have been developed. Among the beta-Ti alloy family, the quaternary Ti–Nb–Zr–Ta (TNZT) alloys have received the highest attention as a promising replacement for Ti6Al4V due to their lower elastic modulus and outstanding long term stability against corrosion in biological environments. However, the inferior wear resistance of TNZT is still a problem that must be resolved before commercialising in the orthopaedic market. In this work, a newly developed laser surface treatment technique was employed to improve the surface properties of Ti–35.3Nb–7.3Zr–5.7Ta alloy. The surface structure and composition of the laser-treated TNZT surface were examined by grazing incidence X-ray diffraction (GI-XRD) and X-ray photoelectron spectroscopy (XPS). The wear and corrosion resistance were evaluated by pin-on-plate sliding test and anodic polarisation test in Hanks’ solution. The experimental results were compared with the untreated (or base) TNZT material. The research findings showed that the laser surface treatment technique reported in this work can effectively improve the wear and corrosion resistance of TNZT.

  19. Effect of heating rate on temperature of titanium alloy (. cap alpha. +. beta. ). -->. beta. transformaton

    Gridnev, V.N.; Ivasishin, O.M.; Markovskij, P.E. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)


    The effect of doping of two-phase titaniums alloys and morphology of initial structure on the Tsub(t) temperature shift value of (..cap alpha..+..beta..)..--> beta.. transformation depending on heating rate is investigated. It has been found that the Tsub(t) shift occurs in the strictly determined temperature range depending on chemical alloy composition. The Tsub(t) shift is directly proportional to the Ksub(..beta..) coefficient applied as a quantitative alloying characteristic as well as a dimensional factor equal either to the plate thickness or the ..cap alpha..-phase globule diameter depending on the type of initial structure. In the limits of this temperature range the (..cap alpha..+..beta..)..--> beta..-transformation occurs completely according to the diffusion mechanism. The critical heating rate at which maximum permissible Tsub(t) value is attained and above which its stabilization is observed is determined by the same parameters - the alloy doping degree characterized by the Ksub(..beta..) coefficient and the ..cap alpha..-phase crystal dimensions in the initial structure.

  20. Incorporation of titanium dioxide nanoparticles in mortars - Influence of microstructure in the hardened state properties and photocatalytic activity

    Lucas, S.S., E-mail: [University of Aveiro/CICECO, Department of Civil Engineering, 3810-193 Aveiro (Portugal); Ferreira, V.M., E-mail: [University of Aveiro/CICECO, Department of Civil Engineering, 3810-193 Aveiro (Portugal); Barroso de Aguiar, J.L., E-mail: [University of Minho, Department of Civil Engineering, Campus de Azurem, 4800-058 Guimaraes (Portugal)


    The environmental pollution in urban areas is one of the causes for poor indoor air quality in buildings, particularly in suburban areas. The development of photocatalytic construction materials can contribute to clean the air and improve sustainability levels. Previous studies have focused mainly in cement and concrete materials, disregarding the potential application in historic buildings. In this work, a photocatalytic additive (titanium dioxide) was added to mortars prepared with aerial lime, cement and gypsum binders. The main goal was to study the way that microstructural changes affect the photocatalytic efficiency. The photocatalytic activity was determined using a reactor developed to assess the degradation rate with a common urban pollutant, NO{sub x}. The laboratory results show that all the compositions tested exhibited high photocatalytic efficiency. It was demonstrated that photocatalytic mortars can be applied in new and old buildings, because the nanoadditives do not compromise the mortar hardened state properties.

  1. Microstructures of beta-titanium orthodontic wires joined by infrared brazing.

    Iijima, Masahiro; Brantley, William A; Kawashima, Isao; Baba, Naoki; Alapati, Satish B; Yuasa, Toshihiro; Ohno, Hiroki; Mizoguchi, Itaru


    The microstructures and interdiffusion in brazed beta-titanium orthodontic wires were investigated by scanning electron microscopy and electron probe microanalysis, respectively. Beta-titanium wire (Ti-11Mo-6Zr-4Sn) with cross-section dimensions of 0.032 in. x 0.032 in., titanium-based braze alloy (Ti-30Ni-20Cu), and silver-based braze alloy (Ag-22Cu-17Zn-5Sn) were selected for the study. Brazing was performed using infrared radiation (RS-1) under an argon atmosphere. Specimens were etched with two solutions (2.5% HF + 2.5% HNO(3) + 95% H(2)O; 25% HN(4)OH + 30% H(2)O(2) + 45%H(2)O). It was found that the silver-based braze alloy has a eutectic structure. In the diffusion layer between the beta-titanium wire and this silver-based braze alloy, Cu and Ti were enriched on the wire side, and Sn and Ti were enriched on the braze alloy side. The titanium-based braze alloy has a dendritic structure. Beta-titanium wire specimens brazed with the titanium-based braze alloy had a thicker intermediate area compared to the silver alloy; Ti in the diffusion layer had an irregular concentration gradient, and the braze alloy side had higher Ti concentration. The original microstructure of the beta-titanium wire was not altered with the use of either braze alloy. Infrared brazing of beta-titanium orthodontic wire is acceptable for clinical use, since the wire microstructure did not deteriorate with either the titanium-based or silver-based braze alloy. The differing microstructures of the joint regions for the two braze alloys suggest that the joint strengths may also differ.

  2. Influence of heating rate on the temperature of the (alpha+beta)-beta transformation of titanium alloys

    Gridnev, V.N.; Ivasishin, O.M.; Markovskii, P.E.


    Results of a systematic experimental study of the effect of the heating rate, composition, and structure on the temperature of the (alpha+beta)-beta transformation in titanium alloys VT6, VT14, VT3-1, VT23, and VT22 are presented. It is shown that the transformation temperature of the alloys increases proportionally to the coefficient k-beta, which characterizes the alloy content, and to the size of the alpha-phase grains in the original structure. All other conditions being equal, the transformation is completed sooner in alloys with a spheroidal structure. 8 references.

  3. Prediction of the martensite start temperature for {beta} titanium alloys as a function of composition

    Neelakantan, Suresh [Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS, Delft (Netherlands); Materials Innovation Institute, Kluyverweg 1, 2629 HS, Delft (Netherlands)], E-mail:; Rivera-Diaz-del-Castillo, P.E.J.; Zwaag, Sybrand van der [Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS, Delft (Netherlands)


    A thermodynamics-based model to predict the martensite start temperature of {beta} titanium alloys is presented. The tendency of the {beta} phase to transform into martensite is estimated by applying the Ghosh-Olson approach to martensite nucleation modelling. The energetics and M{sub s} temperature for binary alloys are predicted with good accuracy. A succinct formula predicting M{sub s} temperature in multicomponent {beta} alloys is presented. The new equation is compared to the classical Mo equivalence criterion for assessing {beta} stability.

  4. Homogenization of. beta. -solid solution during fast heating of two-phase titanium alloys

    Gridnev, V.N.; Zhuravlev, A.F.; Zhuravlev, B.F.; Ivasishin, O.M.; Markovskij, P.E. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)


    Using model alloy Ti-10%Mo as an example the homogenization of high-temperature ..beta..-phase during fast heating has been studied by calculational and experimental methods. The effect of heating rate and the initial structure disoersion on the homogenization is shown. A method is suggested for evaluation of the concentration state of ..beta..-solid solution depleted parts of commercial two-phase titanium alloys. The method has been used to study the homogenization process.

  5. Mechanical properties of ({alpha}+{beta})-titanium alloy at cryogenic temperatures

    Ivasishin, O.M. [Institute for Metal Physics, 36 Vernadsky str, Kiev 252142 (Ukraine); Markovsky, P.E. [Institute for Metal Physics, 36 Vernadsky str, Kiev 252142 (Ukraine); Pakharenko, G.A. [Institute for Metal Physics, 36 Vernadsky str, Kiev 252142 (Ukraine); Shevchenko, A.V. [Institute for Metal Physics, 36 Vernadsky str, Kiev 252142 (Ukraine)


    The influence of microstructure, fine surface stress concentrators and weak surface gas saturation on the mechanical properties of high-strength ({alpha}+{beta})-titanium alloy at cryogenics temperatures was studied. The results are discussed in terms of a new microcleavage model of brittle fracture. (orig.)

  6. Knowledge-based artificial neural network model to predict the properties of alpha+ beta titanium alloys

    Banu, P. S. Noori; Rani, S. Devaki [Dept. of Metallurgical Engineering, Jawaharlal Nehru Technological University, HyderabadI (India)


    In view of emerging applications of alpha+beta titanium alloys in aerospace and defense, we have aimed to develop a Back propagation neural network (BPNN) model capable of predicting the properties of these alloys as functions of alloy composition and/or thermomechanical processing parameters. The optimized BPNN model architecture was based on the sigmoid transfer function and has one hidden layer with ten nodes. The BPNN model showed excellent predictability of five properties: Tensile strength (r: 0.96), yield strength (r: 0.93), beta transus (r: 0.96), specific heat capacity (r: 1.00) and density (r: 0.99). The developed BPNN model was in agreement with the experimental data in demonstrating the individual effects of alloying elements in modulating the above properties. This model can serve as the platform for the design and development of new alpha+beta titanium alloys in order to attain desired strength, density and specific heat capacity.

  7. Trace Carbon in Biomedical Beta-Titanium Alloys: Recent Progress

    Zhao, D.; Ebel, T.; Yan, M.; Qian, M.


    Owing to their relatively low Young's modulus, high strength, good resistance to corrosion, and excellent biocompatibility, β-titanium (Ti) alloys have shown great potential for biomedical applications. In β-Ti alloys, carbon can exist in the form of titanium carbide (TiC x ) as well as interstitial atoms. The Ti-C binary phase diagram predicts a carbon solubility value of 0.08 wt.% in β-Ti, which has been used as the carbon limit for a variety of β-Ti alloys. However, noticeable grain boundary TiC x particles have been observed in β-Ti alloys containing impurity levels of carbon well below the predicted 0.08 wt.%. This review focuses its attention on trace carbon (≤0.08 wt.%) in biomedical β-Ti alloys containing niobium (Nb) and molybdenum (Mo), and it discusses the nature and precipitation mechanism of the TiC x particles in these alloys.

  8. STA heat treatment of beta-titanium alloys after various thermomechanical processing

    Ivasishin, O.M.; Markovsky, P.E.; Teliovich, R.V.; Matviychuk, Yu.V. [AN Ukrainskoj SSR, Kiev (Ukraine). Inst. Fiziki Metallov


    Commercial beta-titanium alloys are promising material for a wide range of applications due to essentially high strength/density ratio, sufficient fatigue performance and crack propagation resistance. Present work was aimed at systematical study the microstructure and mechanical properties of two commercial beta-titanium alloys VT22 and TIMETAL {sup trademark} -LCB in STA condition produced by special heat treatment, comprising from rapid heating into a single-phase beta field and subsequent aging, depending on previous thermomechanical processing employed. Three types of such a processing were studied: hot deformation at temperatures of alpha+beta field, hot deformation in single-phase beta field and cold deformation of as-quenched metastable beta phase. Solid solutionizing by rapid heating has proved to be efficient in receiving fine-grained beta microstructure with average grain size, which varies from 50 {mu}m to 12 {mu}m depending on initial microstructure. Such treatment allowed to obtain on subsequent aging yield strengths up to 1470 MPa while maintaining sufficient ductility. (orig.)

  9. Alloy Design and Thermomechanical Processing of a Beta Titanium Alloy for a Heavy Vehicle Application

    Blue, C.A.; Peter, W.H.


    With the strength of steel, but at half the weight, titanium has the potential to offer significant benefits in the weight reduction of heavy vehicle components while possibly improving performance. However, the cost of conventional titanium fabrication is a major barrier in implementation. New reduction technologies are now available that have the potential to create a paradigm shift in the way the United States uses titanium, and the economics associated with fabrication of titanium components. This CRADA project evaluated the potential to develop a heavy vehicle component from titanium powders. The project included alloy design, development of manufacturing practices, and modeling the economics associated with the new component. New Beta alloys were designed for this project to provide the required mechanical specifications while utilizing the benefits of the new fabrication approach. Manufacturing procedures were developed specific to the heavy vehicle component. Ageing and thermal treatment optimization was performed to provide the desired microstructures. The CRADA partner established fabrication practices and targeted capital investment required for fabricating the component out of titanium. Though initial results were promising, the full project was not executed due to termination of the effort by the CRADA partner and economic trends observed in the heavy vehicle market.

  10. The effect of aging on hydrogen trapping in [beta]-titanium alloys

    Pound, B.G. (SRI International, Menlo Park, CA (United States). Materials Research Center)


    The ingress of hydrogen in three [beta]-titanium alloys (Beta-C, Ti-10V-2Fe-3Al, and Ti-13V-11Cr-3Al) and an [alpha]-[beta] titanium alloy (Ti-6Al-4V) was investigated with a view to characterizing their interaction with hydrogen. A technique referred to as hydrogen ingress analysis by potentiostatic pulsing (HIAPP) was used to obtain anodic current transients for the unaged and aged [beta]-Ti alloys and as-received Ti-6-4 in an acetate buffer (1 mol L[sup [minus]1] HAc/l mol L[sup [minus]1] NaAc, where Ac = acetate). The transients were analyzed using a diffusion/trapping model under interface control conditions to evaluate the trapping constants and hydrogen entry flux in each case. A marked increase in irreversible trapping was observed for the [beta]-titanium alloys with aging and was attributed to precipitation of secondary [alpha] phase. Aging also induced changes in the passive film and hence the hydrogen entry flux. Ti-13-11-3 and Ti-10-2-3 are predicted to become less resistant to hydrogen embrittlement with aging as a result of increase in both the trapping constant (at least for Ti-13-11-3) and the flux. In contrast, the change in resistance of Beta-C Ti with aging is subject to the opposing effects of a reduced flux and an enhanced trapping capability, though the latter appears to have the primary effect, rendering aged Beta-C Ti less resistance to hydrogen embrittlement than the unaged alloy.

  11. Structure of (alpha + beta)-titanium alloys subjected to laser heating

    Ivasishin, O.M.; Markovskii, P.E.; Svechnikov, V.L.; Krasavin, A.P.; Oshkaderov, S.P. (Institut Metallofiziki, Kiev (Ukrainian SSR))


    The structure of surface layers formed in the industrial (alpha + beta)-titanium alloys subjected to pulse-laser treatment with energy density of 5 J/mm is examined. It is shown that as the temperature in the alloys increases, the following sequence of processes occurs: nondiffusion alpha-to-beta transformation; the diffusion redistribution of alloying components in the chemically inhomogeneous beta-phase; and melting and homogenization of the melt. The effect of the initial state of alloys and elastic stresses on the final structure is examined. It is established that the laser treatment with melting, combined with subsequent annealing in the (alpha + beta) region, makes it possible to create the dispersed high-strength state in the surface layer. 11 refs.

  12. Aging response of coarse- and fine-grained {beta} titanium alloys

    Ivasishin, O.M. [G.V.Kurdyumov Institute for Metal Physics, National Academy of Sciences, 03142 Kyiv (Ukraine)]. E-mail:; Markovsky, P.E. [G.V.Kurdyumov Institute for Metal Physics, National Academy of Sciences, 03142 Kyiv (Ukraine); Semiatin, S.L. [Air Force Research Laboratory, AFRL/ML, Wright-Patterson Air Force Base, OH 45433-7817 (United States); Ward, C.H. [Air Force Research Laboratory, AFRL/ML, Wright-Patterson Air Force Base, OH 45433-7817 (United States)


    The effect of heating rate to aging temperature and {beta} grain size on the aging behavior of three metastable {beta} titanium alloys, TIMETAL-LCB, VT22 and Ti-15-3-3-3 ('Ti-15-3'), was established using in situ resistivity measurements, X-ray diffraction, optical microscopy, SEM, TEM and STEM characterization. The results revealed the alloys could be divided into two classes based on their aging behavior. TIMETAL-LCB and VT-22 formed fine plate-like {alpha} at slow heating rates to the aging temperature. This behavior was determined to be due to the precipitation of isothermal {omega} at low temperatures, which serves as nucleation sites for {alpha}. The slow heating rate yielded the best balance of strength and ductility, particularly in alloys with a fine ({approx}10 {mu}m) {beta} grain size. At high heating rates, the formation of isothermal {omega} was avoided, leading to coarse, plate-like {alpha} microstructures with less desirable properties. Ti-15-3, on the other hand, exhibited {beta} phase separation during isothermal aging rather than isothermal {omega} formation. Much slower cooling rates were required to form fine {alpha} laths in Ti-15-3 compared to the other two alloys. The importance of specifying heating rate and aging temperature for the industrial heat treatment of {beta} titanium alloys was thus established.

  13. Influence of beta instabilities on the early stages of nucleation and growth of alpha in beta titanium alloys

    Nag, Soumya

    Microstructural evolution in beta Titanium alloys is an important factor that governs the properties exhibited by them. Intricate understanding of complex phase transformations in these alloys is vital to tailor their microstructures and in turn their properties to our advantage. One such important subject of study is the nucleation and growth of alpha precipitates triggered by the compositional instabilities in the beta matrix, instilled in them during non equilibrium heat treatments. The present work is an effort to investigate such a phenomenon. Here studies have been conducted primarily on two different beta-Titanium alloys of commercial relevance- Ti5553 (Ti-5Al-5Mo-5V-3Cr-0.5Fe), an alloy used in the aerospace industry for landing gear applications and, TNZT (Ti-35Nb-7Zr-5Ta), a potential load bearing orthopedic implant alloy. Apart from the effect of thermal treatment on these alloys, the focus of this work is to study the interplay between different alpha and beta stabilizers present in them. For this, advanced nano-scale characterization tools such as High Resolution STEM, High Resolution TEM, EFTEM and 3D Atom Probe have been used to determine the structure, distribution and composition of the non equilibrium instabilities such as beta' and o, and also to investigate the subsequent nucleation of stable alpha. Thus in this work, very early stages of phase separation via spinodal decomposition and second phase nucleation in titanium alloys are successfully probed at an atomic resolution. For the first time, atomically resolved HRSTEM 'Z'-contrast image is recorded showing modulated structures within the as-quenched beta matrix. Also in the same condition HRTEM results showed the presence of nanoscale alpha regions. These studies are revalidated by conventional selected area diffraction and 3D atom probe reconstruction results. Also TEM dark field and selected are diffraction studies are conducted to understand the effect of quenching and subsequent aging of

  14. A Critical Assessment of Cyclic Softening and Hardening Behavior in a Near- α Titanium Alloy During Thermomechanical Fatigue

    Prasad, Kartik; Sarkar, Rajdeep; Rao, K. Bhanu Sankara; Sundararaman, M.


    Thermomechanical fatigue behavior of Ti-alloy Timetal 834 has been studied at two temperature intervals viz. 573 K to 723 K (300 °C to 450 °C) and 723 K to 873 K (450 °C to 600 °C) under mechanical strain-controlled cycling. Among the temperatures studied, the alloy exhibited initial cyclic softening followed by cyclic hardening at 723 K (450 °C) in the temperature interval of 573 K to 723 K (300 °C to 450 °C). However, continuous cyclic hardening was observed at 723 K (450 °C) in 723 K to 873 K (450 °C to 600 °C). At 573 K (300 °C) and 873 K (600 °C), cyclic softening was observed in the cyclic stress response curves in both the temperature intervals. The dislocation substructure was observed to be planar in both the modes of TMF loading. Based on TEM microstructures and few unconventional fatigue tests, the observed cyclic hardening is attributed to dynamic strain aging. The reduced fatigue life at 723 K to 873 K (450 °C to 600 °C) under OP-TMF loading was attributed to the combined effect of cyclic hardening (leading to early strain localization and crack initiation), oxidation, and development of tensile mean stresses.

  15. Microstructural refinement of weld fusion zones in {alpha}-{beta} titanium alloys using pulsed current welding

    Sundaresan, S.; Janaki Ram, G.D. [Indian Inst. of Technol., Chennai (India). Dept. of Metallurgical Engineering; Madhusudhan Reddy, G. [Defence Metallurgical Research Lab., Hyderabad (India)


    Pulsing of the welding current is one approach for refining the fusion zone grain structure in {alpha}-{beta} titanium alloy welds. This paper reports work in which gas tungsten-arc welds were produced in two {alpha}-{beta} titanium alloys under a variety of conditions including direct current (d.c.) pulsing and alternating current (a.c.) pulsing. The results show that, while d.c. pulsing did also refine the weld metal {beta} grain structure, the effect of a.c. pulsing was much greater. Current pulsing enhances fluid flow, reduces temperature gradients and causes a continual change in the weld pool size and shape. These effects, which are believed to be responsible for refining the solidification structure, are much stronger in a.c. pulsing than in d.c. pulsing. The observed grain refinement was shown to result in an appreciable increase in fusion zone tensile ductility. Post-weld heat treatment improved ductility both in pulsed and unpulsed welds, but pulsed welds showed greater tensile elongation even in the heat treated condition. (orig.) 27 refs.

  16. Formation of L1{sub 0}-type ordered {beta} Prime phase in as-solutionized dental Ag-Pd-Au-Cu alloys and hardening behavior

    Kim, Yonghwan [Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6 Aoba, Aramaki Aza, Aoba-ku, Sendai 980-8579 (Japan); Niinomi, Mitsuo, E-mail: [Department of Biomaterials Science, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Hieda, Junko; Nakai, Masaaki [Department of Biomaterials Science, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Fukui, Hisao [Department of Dental Materials Science, School of Dentistry, Aichi-Gakuin University, Nagoya 464-0045 (Japan)


    The relationship between the microstrucutural changes of L1{sub 0}-type ordered {beta} Prime phase and hardening behavior in as-solutionized dental Ag-Pd-Au-Cu alloys was investigated by changing the cooling rate and the solution treatment temperature. Additionally, the formation process of the {beta} Prime phase in as-solutionized Ag-Pd-Au-Cu alloy was attempted to clarify. The microstructural changes were observed by X-ray diffraction (XRD) method and transmission electron microscopy (TEM). The hardness was evaluated using a Vickers microhardness tester. The {beta} Prime phase is precipitated regardless of the cooling rate, after solution treatment at 1123 K. TEM dark field images show that the size of the {beta} Prime phase decreases and the number of {beta} Prime phase increases with an increase in the cooling rate. The Vickers hardness value increases with an increase in cooling rate. TEM dark field images show that the microstructure of {beta} Prime phase is similar when the solution treatment temperature increases from 1123 K to 1173 K. However, the Vickers hardness increases with an increase of solution treatment temperature. It is of great significance to reveal that the {beta} Prime phase precipitated in as-solutionized Ag-Pd-Au-Cu alloy is formed during cooling after high-temperature solution treatment and that the growth of the {beta} Prime phase is diffusion controlled. - Highlights: Black-Right-Pointing-Pointer The microstructure of {beta} Prime phase of Ag-Pd-Au-Cu alloy is changed by cooling rates. Black-Right-Pointing-Pointer The {beta} Prime phase is formed during the cooling process. Black-Right-Pointing-Pointer Growth of the {beta} Prime phase is dominated by diffusion. Black-Right-Pointing-Pointer Hardness of Ag-Pd-Au-Cu alloy increases remarkably with precipitation of the {beta} Prime phase.

  17. Mechanical properties of low modulus beta titanium alloys designed from the electronic approach.

    Laheurte, P; Prima, F; Eberhardt, A; Gloriant, T; Wary, M; Patoor, E


    Titanium alloys dedicated to biomedical applications may display both clinical and mechanical biocompatibility. Based on nontoxic elements such as Ti, Zr, Nb, Ta, they should combine high mechanical resistance with a low elastic modulus close to the bone elasticity (E=20 GPa) to significantly improve bone remodelling and osseointegration processes. These elastic properties can be reached using both lowering of the intrinsic modulus by specific chemical alloying and superelasticity effects associated with a stress-induced phase transformation from the BCC metastable beta phase to the orthorhombic alpha(″) martensite. It is shown that the stability of the beta phase can be triggered using a chemical formulation strategy based on the electronic design method initially developed by Morinaga. This method is based on the calculation of two electronic parameters respectively called the bond order (B(o)) and the d orbital level (M(d)) for each alloy. By this method, two titanium alloys with various tantalum contents, Ti-29Nb-11Ta-5Zr and Ti-29Nb-6Ta-5Zr (wt%) were prepared. In this paper, the effect of the tantalum content on the elastic modulus/yield strength balance has been investigated and discussed regarding the deformation modes. The martensitic transformation beta-->alpha(″) has been observed on Ti-29Nb-6Ta-5Zr in contrast to Ti-29Nb-11Ta-5Zr highlighting the chemical influence of the Ta element on the initial beta phase stability. A formulation strategy is discussed regarding the as-mentioned electronic parameters. Respective influence of cold rolling and flash thermal treatments (in the isothermal omega phase precipitation domain) on the tensile properties has been investigated.

  18. State of the Art in Beta Titanium Alloys for Airframe Applications

    Cotton, James D.; Briggs, Robert D.; Boyer, Rodney R.; Tamirisakandala, Sesh; Russo, Patrick; Shchetnikov, Nikolay; Fanning, John C.


    Beta titanium alloys were recognized as a distinct materials class in the 1950s, and following the introduction of Ti-13V-11Cr-3Al in the early 1960s, intensive research occurred for decades thereafter. By the 1980s, dozens of compositions had been explored and sufficient work had been accomplished to warrant the first major conference in 1983. Metallurgists of the time recognized beta alloys as highly versatile and capable of remarkable property development at much lower component weights than steels, coupled with excellent corrosion resistance. Although alloys such as Ti-15V-3Al-3Sn-3Cr, Ti-10V-2Fe-3Al and Ti-3AI-8V-6Cr-4Mo-4Zr (Beta C) were commercialized into well-known airframe systems by the 1980s, Ti-13V-11Cr-3Al was largely discarded following extensive employment on the SR-71 Blackbird. The 1990s saw the implementation of specialty beta alloys such as Beta 21S and Alloy C, in large part for their chemical and oxidation resistance. It was also predicted that by the 1990s, cost would be the major limitation on expansion into new applications. This turned out to be true and is part of the reason for some stagnation in commercialization of new such compositions over the past two decades, despite a good understanding of the relationships among chemistry, processing, and performance and some very attractive offerings. Since then, only a single additional metastable beta alloy, Ti-5Al-5V-5Mo-3Cr-0.5Fe, has been commercialized in aerospace, although low volumes of other chemistries have found a place in the biomedical implant market. This article examines the evolution of this important class of materials and the current status in airframe applications. It speculates on challenges for expanding their use.

  19. Fatigue of Beta Processed and Beta Heat-treated Titanium Alloys

    Wanhill, Russell


    This publication reviews most of the available literature on the fatigue properties of β annealed Ti-6Al-4V and titanium alloys with similar microstructures. The focus is on β processed and β heat-treated alloys because β annealed Ti-6Al-4V has been selected for highly loaded and fatigue-critical structures, including the main wing-carry-through bulkheads and vertical tail stubs, of advanced high-performance military aircraft.   An important aspect of the review is a concise survey of fatigue life assessment methods and the required types of fatigue data. This survey provides the background to recommendations for further research, especially on the fatigue behaviour of β annealed Ti-6Al-4V under realistic fatigue load histories, including the essential topic of short/small fatigue crack growth. Such research is required for independent fatigue life assessments that conform to the aircraft manufacturer’s design requirements, and also for life reassessments that most probably will have to be made during...

  20. Studies on single and duplex aging of metastable beta titanium alloy Ti–15V–3Cr–3Al–3Sn

    Santhosh, R. [School of Advanced Sciences, VIT University, Vellore 632 014 (India); Geetha, M. [School of Mechanical and Building Sciences, VIT University, Vellore 632 014 (India); Saxena, V.K. [Defence Metallurgical Research Laboratory, Hyderabad 500 058 (India); Nageswararao, M., E-mail: [School of Mechanical and Building Sciences, VIT University, Vellore 632 014 (India)


    Highlights: • Preaging at 300 °C for 10 h led to an accelerating effect on α precipitation in Ti–15–3 alloy. • Preaging at 250 °C for 24 h led to a finer size and higher density of α precipitates. • Precipitate free zones were seen in the microstructure on aging at 400 and 450 °C. • Duplex aging results in four to five fold higher HCF life compared to single aging. - Abstract: This paper presents the age hardening behavior of metastable beta titanium alloy Ti–15 V–3Cr–3Al–3Sn subjected to various single and duplex aging treatments. Single aging was carried out in the range 200–550 °C for times up to 150 h (h). For duplex aging first step was performed in two different ways: (i) 250 °C for 24 h (ii) 300 °C for 10 h; second step was carried in the range 350–500 °C, for times up to 150 h. The decomposition of alpha (α) phase during aging was monitored by hardness measurements, tensile testing, different microscopic techniques and X-ray diffraction. Duplex aging treatments resulted in higher hardness and strength compared to single aging. There was a good balance of tensile strength and ductility after two duplex aging treatments 300 °C/10 h + 500 °C/10 h and 250 °C/24 h + 500 °C/8 h. Precipitate free zones (PFZs) were observed when aged at ⩽450 °C in the microstructure; aging at ⩾500 °C gave freedom from such zones. Duplex aging resulted in a finer size and higher density of α precipitates compared to single aging. Duplex aging 250 °C/24 h + 500 °C/8 h led to a four to five fold improvement in high cycle fatigue (HCF) life compared to single aging at 500 °C/10 h. The observed improvement in HCF life could thus be related to smaller size and larger density of α precipitates resulting from duplex aging. Optical microscopy and X-ray diffraction studies clearly revealed that preaging for 10 h at 300 °C accelerated the α-phase precipitation reaction during aging.

  1. Fatigue properties of a metastable beta-type titanium alloy with reversible phase transformation.

    Li, S J; Cui, T C; Hao, Y L; Yang, R


    Due to recent concern about allergic and toxic effects of Ni ions released from TiNi alloy into human body, much attention has been focused on the development of new Ni-free, metastable beta-type biomedical titanium alloys with a reversible phase transformation between the beta phase and the alpha'' martensite. This study investigates the effect of the stress-induced alpha'' martensite on the mechanical and fatigue properties of Ti-24Nb-4Zr-7.6Sn (wt.%) alloy. The results show that the as-forged alloy has a low dynamic Young's modulus of 55GPa and a recoverable tensile strain of approximately 3%. Compared with Ti-6Al-4V ELI, the studied alloy has quite a high low-cycle fatigue strength because of the effective suppression of microplastic deformation by the reversible martensitic transformation. Due to the low critical stress required to induce the martensitic transformation, it has low fatigue endurance comparable to that of Ti-6Al-4V ELI. Cold rolling produces a beta+alpha'' two-phase microstructure that is characterized by regions of nano-size beta grains interspersed with coarse grains containing alpha'' martensite plates. Cold rolling increases fatigue endurance by approximately 50% while decreasing the Young's modulus to 49GPa along the rolling direction but increasing it to 68GPa along the transverse direction. Due to the effective suppression of the brittle isothermal omega phase, balanced properties of high strength, low Young's modulus and good ductility can be achieved through ageing treatment at intermediate temperature.

  2. Kinetics and thermodynamics of hydrogen absorption and release in {beta}-titanium alloys; Kinetik und Thermodynamik der Wasserstoffaufnahme und -abgabe von {beta}-Titanlegierungen

    Decker, M.; Christ, H.J. [Siegen Univ. (Gesamthochschule) (Germany). Inst. fuer Werkstofftechnik


    The work reported was intended to yield results allowing to describe as completely as possible the processes of interaction of {beta}-titanium and hydrogen. Three alloys have been selected for the experiments which suitably differ in stability of the {beta} phase. The characterisation of the hydrogen/metal interactions is primarily based on gravimetric measurements. A method was found to determine the diffusion coefficient of hydrogen, which is a significant variable for quantitative characterisation of the hydrogen absorption rate. (orig./CB) [Deutsch] In der Arbeit wird eine moeglichst vollstaendige Beschreibung der Wechselwirkung von {beta}-Titanlegierungen mit Wasserstoff angestrebt. Hierfuer wird mit drei Legierungen gearbeitet, die sich hinsichtlich der Stabilitaet der {beta}-Phase in sinnvoll abgestufter Weise unterscheiden. Fuer die Charakterisierung der Wasserstoff/Metall-Wechselwirkung wurden insbesondere gravimetrische Messungen eingesetzt. Weiterhin wurde die fuer eine quantitative Beschreibung der Wasserstoffaufnahmegeschwindigkeit wichtige Groesse des Diffusionskoeffizienten von Wasserstoff mit einem Verfahren bestimmt. (orig./MM)

  3. Deformasi Slot Beberapa Produk Braket Stainless Steel Akibat Gaya Torque Kawat Beta Titanium

    Marisa Mifta Huda


    Full Text Available Deformasi slot braket Stainless Steel akan mempengaruhi gaya yang diaplikasikan kepada gigi.Tujuan penelitian adalah untuk mengetahui deformasi slot braket dari lima merek braket yaitu 3M, Biom, Versadent, Ormco dan Shinye akibat gaya torque kawat Beta Titanium 0.021x0.025 inci dengan sudut puntir 45° dan besar gaya torque dengan sudut puntir 30° dan 45°. Penelitian juga bertujuan untuk membandingkan deformasi dan besar gaya torque antara kelima merek braket. Penelitian dilakukan pada 50 braket Stainless Steel Edgewise dari lima kelompok merek braket (n=10 dilem ke akrilik. Masing-masing braket dilakukan dua tahapan pengukuran yaitu pengukuran deformasi braket dengan menghitung rerata tinggi slot braket dengan mikroskop stereoskopi sebelum dan sesudah uji torque dan pengukuran besar gaya torque dengan alat uji torque. Hasil analisa statistik menunjukkan terdapat deformasi slot braket pada kelima merek braket dengan deformasi permanen secara klinis pada braket Biom (2,79 µm dan Shinye (2,29 µm. Besar gaya torque pada kelima braket dari yang paling besar yaitu 3M, Ormco, Versadent, Shinye dan Biom. Perbandingan deformasi slot braket dan besar gaya torque antara kelima braket adalah terdapat perbedaan deformasi slot braket antara kelima merek braket kecuali antara 3M dan Ormco dan Biom dan Shinye dan terdapat perbedaan besar gaya torque antara kelima braket dengan sudut puntir 30° (kecuali 3M dan Ormco dan 45°. Kesimpulan, Komposisi logam dan proses pembuatan braket merupakan faktor yang mempengaruhi terjadinya deformasi slot braket dan besar gaya torque. Proses pembuatan dengan metode MIM dan komposisi logam AISI 303 dan 17-4PH menurunkan risiko deformasi. Slot Deformation in Various Stainless Steel Bracket Products due to The Torqueing Force of Beta Titanium Wire. Stainless Steel bracket slot deformation affects force applied to teeth. The research aims to determine slot deformation of five different bracket brands namely, 3M, Biom

  4. TC4钛合金真空脉冲渗氧硬化层的组织与性能%Microstructure and Properties of Vacuum Pulse Oxidation Hardening Layer on TC4 Titanium Alloy

    杨闯; 马亚芹; 王亮


    A hardened layer possessing good bonding strength with substrate was prepared on the surface of TC4 titanium alloy by a process of vacuum pulse oxidation.The microstructure,hardness and brittleness of hardening layer were analyzed.The results show the hardened layer comprises a surface oxide layer and an oxygen diffusion zone,TiO2 of the oxide layer happen to change,oxygen penetrate into the substrate,the phase of oxide layer is composed of α-Ti,rutile TiO2,TiO and Ti3Al,surface microstructure appear compact,the surface hardness of the TC4 titanium are 650 ~ 670HV,the thickness of the hardened layer can reach 60 ~ 80 μm,because of the effect of solid solution strengthening in oxygen diffusion zone,the hardened layer has low brittleness and the hardness gradient of hardened zone is fiat.%采用真空脉冲渗氧的方法,在TC4钛合金表面制备了与基体结合良好的硬化层,并对硬化层的组织结构、硬度、脆性等进行了分析.结果表明:硬化层由表面氧化物层和氧扩散区组成,氧化层中TiO2发生了分解,氧向基体内扩散,氧化层主要由α-Ti、金红石TiO2、TiO及少量Ti3Al组成,表层组织致密,表面硬度为650~670HV,硬化层深度可达60 ~ 80 μm;此外,由于扩散区氧的固溶强化作用,硬化层的硬度梯度平缓,脆性小.

  5. Characteristics of continuous cooling transformation in [alpha]+[beta] titanium alloys. [alpha]+[beta] gata gokin no hentai soshikii keisei model to netsukan ensei teika gensho no kaimei

    Fujii, H. (Nippon Steel Corp., Tokyo (Japan))


    When [alpha]+[beta] titanium alloys are subject to a [beta] process, i.e. the alloys are heated to the [beta] region; the temperature is maintained; and then the alloy are cooled, they present several transformation microstructures depending on cooling speeds. In this study, the cooling speed from the [beta] region was varied to examine the effect of cooling speed on the formation of microstructures. This effect is now undergoing continued examination. In this study, using Ti-6Al-4V and Ti-6Al-6V-2Sn alloys, the diffusion transformation was especially examined and the following results were obtained: the diffusion transformation develops by generation of side-plate [alpha]-phase instead of growth of grain boundary [alpha]-phase. For such the structural behavior, based on the assumption that vanadium which concentrates near the grain boundary [alpha]-phase in early stages of the transformation plays an important role, a model of formation mechanism of Widmanstatten microstructure is developed. The ductility loss of the Widmanstatten microstructure in the specified [alpha]+[beta] temperature range can be explained by the model which presents the solution that the loss is a result of generation of the special microstructure region containing the soft [beta]-phase at higher percentage along the grain boundary [alpha]-phase. 21 refs., 10 figs., 1 tab.

  6. TA2钛材的激光相变硬化复合低温气体渗氮工艺%Laser transformation hardening enhanced cryogenic gas nitriding process of TA2 titanium

    韩彬; 付现桥; 曹宁; 王勇


    To improve the abrasion resistance and corrosion resistance of TA2 titanium, a laser transformation hardening-gas nitriding process was adopted to carry out the surface modification. Analysis was made for the surface morphology, microstructure and phase constitution of TA2 laser transformation hardening-gas nitrided layer by OM, TEM and XRD;and microhardness tester was used to test the microhardness of the two composite modified surfaces. The results indicate that after undergoing laser transformation hardening, the surface of TA2 titanium can be nitrided at a low temperature of 430 ℃. Under this condition, the grains are refined. The increase in sub-structure and defect density is more conducive to the intragranular diffusion of nitrogen, and there is a good correspondence between the phase transformation structure and nitrogen potential gradient. TA2 titanium surface-hardened layer with good performance is obtained through improving the structure of nitrided layer and the distribution of its chemical components.%为了提高TA2钛合金的耐磨性和耐蚀性,采用激光相变硬化-气体渗氮工艺对TA2钛进行表面改性。利用体视光学显微镜、透射电镜和X射线衍射仪对TA2激光相变硬化-气体渗氮层进行表面形貌、微观组织和相组成分析;利用显微硬度计对两种复合改性层的显微硬度进行测试。结果表明:TA2钛表面经激光相变硬化后,可实现430℃低温渗氮。此条件下晶粒得到细化,亚结构和缺陷密度的增加有利于氮元素和晶内扩散,相变组织与氮势梯度具有良好的对应关系。通过改善渗层的组织结构和化学成分分布状态,获得了性能优良的TA2钛表面硬化层。

  7. Titanium

    Fage, Simon W; Muris, Joris; Jakobsen, Stig S


    Exposure to titanium (Ti) from implants and from personal care products as nanoparticles (NPs) is common. This article reviews exposure sources, ion release, skin penetration, allergenic effects, and diagnostic possibilities. We conclude that human exposure to Ti mainly derives from dental...... and medical implants, personal care products, and foods. Despite being considered to be highly biocompatible relative to other metals, Ti is released in the presence of biological fluids and tissue, especially under certain circumstances, which seem to be more likely with regard to dental implants. Although...... most of the studies reviewed have important limitations, Ti seems not to penetrate a competent skin barrier, either as pure Ti, alloy, or as Ti oxide NPs. However, there are some indications of Ti penetration through the oral mucosa. We conclude that patch testing with the available Ti preparations...

  8. Microstructural evolutions in warm compression of Betacez and 6246 titanium alloys and influence of the forging on the transformation {beta} {yields} {alpha}; Evolutions microstructurales en compression a chaud des alliages de titane Betacez et 6246 et influence du forgeage sur la transformation {beta} {yields} {alpha}

    Chaussy Mraizika, F.


    The relations between the thermomechanical ranges and the microstructures of titanium alloys are still insufficient. This work proposes to improve the knowledge of structural state coming from the {beta} forging and the ulterior transformation {beta} to {alpha}+{beta}. The influence of the two parameters, rate and strain speed, on the microstructural and textural evolutions appear during the forging and also during the {beta}/{alpha} transformation are systematically studied. The two titanium alloys which are studied are Betacez titanium alloy and the 6246 titanium alloy. (N.C.)

  9. A low-cost hierarchical nanostructured beta-titanium alloy with high strength.

    Devaraj, Arun; Joshi, Vineet V; Srivastava, Ankit; Manandhar, Sandeep; Moxson, Vladimir; Duz, Volodymyr A; Lavender, Curt


    Lightweighting of automobiles by use of novel low-cost, high strength-to-weight ratio structural materials can reduce the consumption of fossil fuels and in turn CO2 emission. Working towards this goal we achieved high strength in a low cost β-titanium alloy, Ti-1Al-8V-5Fe (Ti185), by hierarchical nanostructure consisting of homogenous distribution of micron-scale and nanoscale α-phase precipitates within the β-phase matrix. The sequence of phase transformation leading to this hierarchical nanostructure is explored using electron microscopy and atom probe tomography. Our results suggest that the high number density of nanoscale α-phase precipitates in the β-phase matrix is due to ω assisted nucleation of α resulting in high tensile strength, greater than any current commercial titanium alloy. Thus hierarchical nanostructured Ti185 serves as an excellent candidate for replacing costlier titanium alloys and other structural alloys for cost-effective lightweighting applications.

  10. Electrochemical behavior of near-beta titanium biomedical alloys in phosphate buffer saline solution.

    Dalmau, A; Guiñón Pina, V; Devesa, F; Amigó, V; Igual Muñoz, A


    The electrochemical behavior of three different near-β titanium alloys (composed by Ti, Nb and Sn) obtained by powder metallurgy for biomedical applications has been investigated. Different electrochemical and microscopy techniques were used to study the influence of the chemical composition (Sn content) and the applied potential on the microstructure and the corrosion mechanisms of those titanium alloys. The addition of Sn below 4wt.% to the titanium powder improves the microstructural homogeneity and generates an alloy with high corrosion resistance with low elastic modulus, being more suitable as a biomaterial. When the Sn content is above 4%, the corrosion resistance considerably decreases by increasing the passive dissolution rate; this effect is enhanced with the applied potential.

  11. Tribocorrosion behavior of beta titanium biomedical alloys in phosphate buffer saline solution.

    Pina, V Guiñón; Dalmau, A; Devesa, F; Amigó, V; Muñoz, A Igual


    The tribo-electrochemical behavior of different β titanium alloys for biomedical applications sintered by powder metallurgy has been investigated. Different mechanical, electrochemical and optical techniques were used to study the influence of the chemical composition, Sn content, and the electrochemical conditions on the tribocorrosion behavior of those alloys Ti30NbxSn alloys (where "x" is the weight percentage of Sn content, 2% and 4%). Sn content increases the active and passive dissolution rate of the titanium alloys, thus increasing the mechanically activated corrosion under tribocorrosion conditions. It also increases the mechanical wear of the alloy. Prevailing electrochemical conditions between -1 and 2V influences the wear accelerated corrosion by increasing it with the applied potential and slightly increases the mechanical wear of Ti30Nb4Sn. Wear accelerated corrosion can be predicted by existing models as a function of electrochemical and mechanical parameters of the titanium alloys.

  12. Fundamental Studies on Ambient Temperature Creep Deformation Behavior of Alpha and Alpha-Beta Titanium Alloys


    Electron Microscope Elemental tin t time T Ta temperature Elemental Tantalum TEM Ti Transmission Electron Microscope Elemental titanium Ti...7 [45] and 8 [46]. The chemical compositions are actual chemical compositions of the alloys after fabrication as determined by the wet chemistry

  13. A low-cost hierarchical nanostructured beta-titanium alloy with high strength

    Devaraj, Arun; Joshi, Vineet V.; Srivastava, Ankit; Manandhar, Sandeep; Moxson, Vladimir; Duz, Volodymyr A.; Lavender, Curt


    Lightweighting of automobiles by use of novel low-cost, high strength-to-weight ratio structural materials can reduce the consumption of fossil fuels and in turn CO2 emission. Working towards this goal we achieved high strength in a low cost β-titanium alloy, Ti–1Al–8V–5Fe (Ti185), by hierarchical nanostructure consisting of homogenous distribution of micron-scale and nanoscale α-phase precipitates within the β-phase matrix. The sequence of phase transformation leading to this hierarchical nanostructure is explored using electron microscopy and atom probe tomography. Our results suggest that the high number density of nanoscale α-phase precipitates in the β-phase matrix is due to ω assisted nucleation of α resulting in high tensile strength, greater than any current commercial titanium alloy. Thus hierarchical nanostructured Ti185 serves as an excellent candidate for replacing costlier titanium alloys and other structural alloys for cost-effective lightweighting applications. PMID:27034109

  14. Hydrogen and sliding at alpha/beta interfaces of titanium alloys

    Margolin, Harold


    Emerging evidence that the sliding between alpha and beta interfaces reported in both Ti-Mn alloys and the Ti-4.5Al-5Mo-1.5Cr ('Corona 5') alloy at room temperature is associated with hydrogen suggests that this may be a general problem contributing to Ti alloys' room-temperature creep. The present evaluation of experimental data indicates that while the hydrogen is concentrated at the Ti-Mn alloys' beta phase, no hydride formation at the alpha/beta interfaces has been reported for either the Ti-Mn alloys or Corona 5. If a hydrogen flux is needed, sliding at the alpha-beta interfaces should be a function of total hydrogen content in the alloy.

  15. Nanocrystalline [beta]-Ta Coating Enhances the Longevity and Bioactivity of Medical Titanium Alloys

    Linlin Liu; Jiang Xu; Shuyun Jiang


      A [beta]-Ta nanocrystalline coating was engineered onto a Ti-6Al-4V substrate using a double cathode glow discharge technique to improve the corrosion resistance and bioactivity of this biomedical alloy...

  16. Adhesion wear mechanisms under dry friction of titanium alloys in vacuum

    Lebedeva, I.L.; Presnyakova, G.N. (Physico-Technical Inst. for Low Temperature Physics and Engineering, Ukrainian Academy of Sciences, Kharkov (Ukrainian SSR))


    Physicochemical processes taking place in the surface layers of titanium alloys were studied. For vacuum conditions, a range of external parameters was proved to exist where the alloys have high wear resistance and a low coefficient of friction. The transition from seizure, with tearing of the material at a large depth, to fatigue wear is related to surface hardening due to {alpha} {r reversible} {beta} transitions under friction. Thermodynamic parameters were calculated and the criteria of protective secondary structure formation defined. (orig.).

  17. Homogenization of. beta. -solid solution upon rapid heating of two-phase titanium alloys

    Grudnev, V.N.; Zhuravlav, A.F.; Zhuravlev, B.F.; Ivasishin, O.M.; Markovskiy, P.E.


    High temperature ..beta.. phase homogenization during rapid heating was studied in a Ti-Mo alloy by mathematical simulation and experimental observation. The method used allows quantitative estimation of the influence of the two major factors determining development of the process of homogenization of the ..beta.. solid solution: heating rate and initial structure dispersion. Successive quenching of specimens from increasing temperatures in the ..beta.. area provides a simple and reliable method of observing the process of homogenization. This method allows experimental development of equations similar to those calculated for the ..beta.. solid solution area with minimum alloying element content. The experimental and calculated results are similar for a heating rate of 300/sup 0/K per second. Heating rate and initial structure dispersion are found to be quite significant in the Ti-10% Mo alloy studied. A method is suggested for estimating the concentration state of impoverished sectors of the ..beta.. solid solution in commercial alloys during rapid heating and used to analyze the inhomogenization. 8 references, 6 figures.

  18. A low-cost hierarchical nanostructured beta-titanium alloy with high strength

    Devaraj, Arun; Joshi, Vineet V.; Srivastava, Ankit; Manandhar, Sandeep; Moxson, Vladimir; Duz, Volodymyr A.; Lavender, Curt


    Lightweighting of automobiles by use of novel low-cost, high strength-to-weight ratio structural materials can reduce the consumption of fossil fuels and in turn CO2 emission. Working towards this goal we achieved high strength in a low cost β-titanium alloy, Ti–1Al–8V–5Fe (Ti185), by hierarchical nanostructure consisting of homogenous distribution of micron-scale and nanoscale α-phase precipitates within the β-phase matrix. The sequence of phase transformation leading to this hierarchical na...

  19. Loss of coherency of the alpha/beta interface boundary in titanium alloys during deformation

    Zherebtsov, Sergey; Salishchev, Gennady; Semiatin, S. Lee


    The loss of coherency of interphase boundaries in two-phase titanium alloys during deformation was analyzed. The energy of the undeformed interphase boundary was first determined by means of the van der Merwe model for stepped interfaces. The subsequent loss of coherency was ascribed to the increase of interphase energy due to absorption of lattice dislocations and was quantified by a relation similar to the Read-Shockley equation for low-angle boundaries in single-phase alloys. It was found that interphase boundaries lose their coherency by a strain of approximately 0.5 at T = 800°C.

  20. Single-pulse KrF laser ablation and nanopatterning in vacuum of {beta}-titanium alloys used in biomedical applications

    Guillemot, F.; Porte-Durrieu, M.C.; Baquey, C. [INSERM U-577, Biomateriaux et Reparation Tissulaire, 146 rue Leo Saignat, 33076, Bordeaux cedex (France); Prima, F. [ENSCP, Laboratoire de Metallurgie Structurale, 11 rue Pierre et Marie Curie, 75231, Paris cedex 05 (France); Tokarev, V.N.; Belin, C.; Lazare, S. [CNRS UMR-5803, Laboratoire de Physico-Chimie Moleculaire, 351 cours de la Liberation, 33405, Talence cedex (France); Gloriant, T. [INSA, Groupe de Recherche en Chimie et Metallurgie, 20 av. des Buttes de Coesmes, 35043, Rennes cedex (France)


    We report the KrF laser (248 nm) nanosecond single-pulse irradiation in vacuum of a mirror-polished surface of a model {beta}-titanium alloy. A series of single-pulse laser-annealing experiments is performed with increasing fluence adjusted to obtain conditions from submelting (a few mJ/cm{sup 2}) up to intense laser ablation (30 J/cm{sup 2}). The structural and morphological changes are followed by atomic force microscopy and scanning electron microscopy, as well as with other analytical techniques, and compared with the starting {alpha}{beta} equilibrium mixture of the untreated sample. The results are discussed and related to the theoretical estimation of fluences corresponding to the {beta}-transus, melting, boiling and intense ablation (phase-explosion) thresholds as well as to the estimates of melt depth and lifetime evaluation as a function of fluence. By carrying out laser annealing in vacuum the surface oxidation is avoided while roughening and phase transformations are favoured within the laser-heated depth. The mirror-polished starting surface is composed of nanometric {alpha}-precipitates embedded in a {beta}-matrix, whose surface is systematically 5-10 nm above the {alpha}-surface. Upon laser annealing with increasing fluence the {alpha}-nanocrystals transform progressively into {beta}-phase, resulting in an increasing relief. At higher fluence the conditions for increasing roughness are studied. Submicrometre roughness is expected to improve cell adhesion to {beta}-titanium alloys and hence osteointegration. (orig.)

  1. Phase Stability and Stress-Induced Transformations in Beta Titanium Alloys

    Kolli, R. Prakash; Joost, William J.; Ankem, Sreeramamurthy


    In this article, we provide a brief review of the recent developments related to the relationship between phase stability and stress-induced transformations in metastable body-centered-cubic β-phase titanium alloys. Stress-induced transformations occur during tensile, compressive, and creep loading and influence the mechanical response. These transformations are not fully understood and increased understanding of these mechanisms will permit future development of improved alloys for aerospace, biomedical, and energy applications. In the first part of this article, we review phase stability and discuss a few recent developments. In the second section, we discuss the current status of understanding stress-induced transformations and several areas that require further study. We also provide our perspective on the direction of future research efforts. Additionally, we address the occurrence of the hcp ω-phase and the orthorhombic α″-martensite phase stress-induced transformations.

  2. Reductive dechlorination of alpha-, beta-, delta-, and gamma-hexachlorocyclohexane isomers by hydroxocobalamin in the presence of either dithiothreitol or titanium(III) citrate as reducing agents.

    Rodríguez-Garrido, B; Arbestain, M Camps; Monterroso, M C; Macías, F


    The effect of the reducing potential on the reductive dehalogenation of the different HCH (hexachlorocyclohexane) isomers has not yet been studied. In the present study, the potential for dehalogenation of (alpha-, beta-, delta-, and gamma-HCH isomers by the dithiothreitol (DTT) and titanium(III) citrate (reducing potential at pH 7, -0.33 and -0.48 V, respectively), with and without the addition of hydroxocobalamin was investigated. In the presence of DTT without catalyst, there was no disappearance of any of the HCH isomers studied after 1 h of treatment. However, disappearance of the gamma- and alpha-HCH isomers was observed during the same time period when titanium(III) citrate was used as the reductant in the absence of catalyst (62.9 and 16.6% disappearance, respectively). Addition of the hydroxocobalamin to the DTT system favored mainly the disappearance of gamma- and alpha-HCH (92.9 and 30.8% disappearance after 1 h, respectively); disappearance of delta-HCH and beta-HCH was small (11.9%) or negligible, respectively. Addition of the hydroxocobalamin to the titanium(III) citrate system favored the degradation of all HCH isomers under study: beta- and alpha-HCH completely disappeared to undetectable levels ( alpha-HCH > delta-HCH > beta-HCH, coincided with a decreasing order of the axially positioned Cl atoms of these isomers (considering their thermodynamically most stable configuration). This study is the first description of the rapid degradation of delta- and beta-HCH under abiotic conditions, and the results demonstrate the effect of the reducing potential on the reductive dehalogenation of HCH isomers.

  3. Microcrack formation in high-deformed titanium alloy

    Gridnev, V.N.; Ivasishin, O.M.; Svechnikov, V.L. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)


    ..cap alpha..-phase interlayers on the ..cap alpha../..beta.. boundary with orientation different from a matrix alloys can act as cause of titanium alloys hardening with simultaneous decrease of their ductility. Electron microexamination of the structure of ..cap alpha..-phase located both on interfaces and in ..cap alpha..-grain volume provides evidence that deformation twinning on different planes and slip in a matrix ..cap alpha..-phase are the mechanism of the ..cap alpha..-phase formation. Examples of ..cap alpha..-phase participation with orientation different from the matrix one are presented in the process of microcracks formation.

  4. A comparative study of elemental components and mechanical properties of beta-titanium alloy wires%四种Beta-钛正畸弓丝合金成分及力学性能的比较研究

    张颖; 李兴; 杨凯; 尤力; 宋西平


    目的 比较四种Beta-钛正畸弓丝的合金成分及力学性能,为临床选择提供参考.方法 选用EDAX X-射线能谱分析仪,联合SUPRA55热场发射扫描电子显微镜(SEM)分析弓丝的合金元素成分.采用纳米压痕技术测定弓丝纳米弹性模量及硬度;采用三点弯曲试验方法测定弓丝负荷-形变曲线,比较弓丝的力学性能.结果 四种Beta-钛丝合金成分中均含有Ti、Zr、Mo、Sn四种元素,Ti在四种Beta-钛丝中所占比重均高于70%.Ormco和Masel公司的Beta-钛丝弹性模量小于Smart与GAC公司的Beta-钛丝.GAC的Beta-钛丝硬度最大.当形变3mm的负荷完全去除时,四种Beta-钛丝均有残余形变,Smart和Ormco大于GAC和Masel公司的Beta-钛丝残余形变.结论 四种Beta-钛丝合金成分基本相同,力学性能有一定差异,可根据临床实际情况选取合适弓丝.%Objective To compare the elemental components and mechanical properties of Beta-titanium alloy wires from four different companies. Methods Beta-titanium alloy wires from Ormco, Masel, Smart and GAC company were selected in this study. Energy dispersive microanalysis of X-RAY and SUPRATm55 scanning electron microscope were used to analyze the alloy compositions. Nano Indenter XP was used to test elasticity modulus and hardness of Beta-titanium alloy wires. Three-Bending Test was performed to compare the differences in mechanical properties. Results All the wires tested contained Ti,and Ti accounted for more than 70% in weight. The values of elasticity modulus were lower in Ormco and Masel than in GAC and Smart The value of hardness was highest in GAC. There were residual deformations in all the wires when unloaded from 3mm deflection. The residual deformation was larger in Smart and Ormco than in GAC and MaseL Conclusion The elemental components of four kinds of Beta-titanium alloy wires were almost the same, but differences existed in mechanical properties. It suggests that we choose proper wires

  5. Fatigue crack growth behaviors of a new burn-resistant highly-stabilized beta titanium alloy

    WU Huan; ZHAO Yongqing; ZENG Weidong; QIAN Li


    This article presents the fatigue crack growth (FCG) behaviors of a new burn-resistant highly-stabilized beta Ti40 alloy. The FCG rotes were analyzed. The fracture surfaces and the side surfaces of the test samples were explored. The results show that frequency affects the cracking behaviors of Ti40 alloy. Temperature also plays an important role in Ti40 alloy cracking. At room temperature (25℃), when the frequency increases, the cracking rate changes a little in the range of low stress intensity factor (ΔK), while it changes significantly when ΔK is high. At 500℃, the cracking rate of Ti40 alloy changes significantly during all the course of clacking. The frequency also affects the microstructure patterns of Ti40 alloy. A number of secondary cracks appear in the area more than 200 μm from the main crack at a high ΔK when the fre-quency is 1 Hz, but only a few secondary cracks exist when the frequency is 10 Hz. Facet image is the main image of the fracture surfaces when the frequency is 1 Hz. While, ductile striation occupies most of the area of fracture surfaces when the frequency is 10 Hz.

  6. A hardenability test proposal

    Murthy, N.V.S.N. [Ingersoll-Rand (I) Ltd., Bangalore (India)


    A new approach for hardenability evaluation and its application to heat treatable steels will be discussed. This will include an overview and deficiencies of the current methods and discussion on the necessity for a new approach. Hardenability terminology will be expanded to avoid ambiguity and over-simplification as encountered with the current system. A new hardenability definition is proposed. Hardenability specification methods are simplified and rationalized. The new hardenability evaluation system proposed here utilizes a test specimen with varying diameter as an alternative to the cylindrical Jominy hardenability test specimen and is readily applicable to the evaluation of a wide variety of steels with different cross-section sizes.

  7. Dynamic behaviour and shock-induced martensite transformation in near-beta Ti-5553 alloy under high strain rate loading

    Wang Lin


    Full Text Available Ti-5553 alloy is a near-beta titanium alloy with high strength and high fracture toughness. In this paper, the dynamic behaviour and shock-induced martensite phase transformation of Ti-5553 alloy with alpha/beta phases were investigated. Split Hopkinson Pressure Bar was employed to investigate the dynamic properties. Microstructure evolutions were characterized by Scanning Electronic Microscopy and Transmission Electron Microscope. The experimental results have demonstrated that Ti-5553 alloy with alpha/beta phases exhibits various strain rate hardening effects, both failure through adiabatic shear band. Ti-5553 alloy with Widmannstatten microstructure exhibit more obvious strain rate hardening effect, lower critical strain rate for ASB nucleation, compared with the alloy with Bimodal microstructures. Under dynamic compression, shock-induced beta to alpha” martensite transformation occurs.

  8. Synthesis, molecular structure (X-ray and DFT), and solution behavior of titanium 4-Acyl-5-pyrazolonates. Correlations with related antitumor beta-diketonato derivatives.

    Caruso, Francesco; Pettinari, Claudio; Marchetti, Fabio; Natanti, Paolo; Phillips, Christine; Tanski, Joseph; Rossi, Miriam


    Previously reported structure-activity relationships have shown two features for effective antitumor activity of titanium beta-diketone complexes: (a) ligand asymmetry and (b) the presence of planar substitutents on the ligand. Mono- and dinuclear derivatives, studied with diffraction and DFT methods show that (a) is consistent with different Ti-O(beta-diketonato) bond lengths, which are longer than Ti-O(oxo) and Ti-O(alkoxy) ones. pi-pi features observed in dinuclear derivatives correlate with strong reactivity of related complexes with DNA and support DNA intercalation by such planar groups, in agreement with (b). Large variation for Ti-O bond lengths and Ti-O-C bond angles in the ethoxy moiety is associated with the titanium withdrawing effect and oxygen bonding s character; it is confirmed through exploration of the Cambridge crystallographic database. This ethoxy geometrical flexibility also suggests versatile accommodation in protein pockets and/or other biological targets. Electrospray ionization mass spectrometry (ESI-MS) spectra show formation of di- and trinuclear Ti-4-acyl-5-pyrazolonato cationic oligomers. Hydrolysis/oligomerization is also described by NMR results.

  9. Contribution to phase transformation modeling in titanium alloys. Application on {beta}-CEZ alloy; Contribution a la modelisation des transformations de phases dans les alliages de titanes: application a l'alliage {beta}-CEZ

    Hericher, L.


    In order to predict the phase transformation kinetics and the amount of alpha phase of the different morphologies, it is thus necessary to model each transformation mechanism. The developed model describing transformation kinetics by nucleation and growth laws for a multi-component titanium alloy. A new description of alpha phase compound (stoichiometric compound) in the existing titanium data base in the software Thermo-Calc allows to obtain a good correlation between experimental and calculated results. In order to study the growth of alpha spheroids after solubilization in the alpha+beta range we have shown that it is necessary to consider a numerical approach to obtain a good prediction of the transformation kinetics. The transformation kinetics after solubilization in the beta range is obtained by combining the models of nucleation and growth of the different morphologies. A geometrical structure was assumed, close to the real grain one. This allows to estimate some microstructural parameters that can be compared to the experimental observations. Experimental and calculated IT (and CGT) diagrams appear to be very close. (author)

  10. [Hardening of dental instruments].

    Gerasev, G P


    The possibility of prolonging the service life of stomatological instruments by the local hardening of their working parts is discussed. Such hardening should be achieved by using hard and wear-resistant materials. The examples of hardening dental elevators and hard-alloy dental drills are given. New trends in the local hardening of instruments are the treatment of their working parts with laser beams, the application of coating on their surface by the gas-detonation method. The results of research work and trials are presented.

  11. Hot deformation behavior and microstructural evolution of beta C titanium alloy in β phase field%Beta C钛合金在β相区的热变形行为及组织演化

    许鑫; 董利民; 巴宏波; 张志强; 杨锐


    利用 Gleeble−3800热模拟试验机对 beta C 钛合金进行等温压缩试验,研究其在β相区的热变形行为。得到了描述热变形行为的本构方程,获得了真应变为0.7时的加工图。采用光学显微镜、扫描电子显微镜和电子背散射技术对变形显微组织进行表征。结果表明:流变应力随着应变速率加快而增大,随着试验温度的升高而减小。计算得到的表观激活能为167 kJ/mol,接近β钛的自扩散激活能。加工图和显微组织观察表明在温度为900~1000°C和变形速率为0.1~1 s−1的区间存在一个动态再结晶区。加工图显示,当变形速率大于1.7 s−1时,beta C 钛合金发生不稳定变形。Beta C 钛合金在动态再结晶区变形后,经合适的热处理,显微组织可以被优化。%The hot deformation behavior of beta C titanium alloy in β phase field was investigated by isothermal compression tests on a Gleeble−3800 thermomechanical simulator. The constitutive equation describing the hot deformation behavior was obtained and a processing map was established at the true strain of 0.7. The microstructure was characterized by optical microscopy (OM), scanning electron microscopy (SEM) and electron back-scattered diffraction (EBSD) technique. The results show that the flow stress increases with increasing strain rates, and decreases with increasing experimental temperatures. The calculated apparent activation energy (167 kJ/mol) is close to that of self-diffusion in β titanium. The processing map and microstructure observation exhibit a dynamic recrystallization domain in the temperature range of 900−1000 °C and strain rate range of 0.1−1 s−1. An instability region exists when the strain rate is higher than 1.7 s−1. The microstructure of beta C titanium alloy can be optimized by proper heat treatments after the deformation in the dynamic recrystallization domain.

  12. Aging properties and microstructures of Ti-B20 titanium alloy

    GE Peng; ZHAO Yong-qing; ZHOU Lian


    A new metastable beta titanium alloy of Ti-Al-Mo-V-Cr-Fe-Zr-Sn system was designed and named Ti-B20. In order to investigate the aging properties and microstructures of the new alloy subjected to different solution treatments, the tensile and Vickers hardness tests were carried out and the optical microscope and scanning electron microscope analysis were performed. The results show that the new alloy displays rapid aging response, high age strengthening effect and fine deposition. In addition, beta solution results in ultra high age hardening effect with low tensile ductility, whereas excellent combination of aging strength and ductility can be obtained after solution treated below beta transus temperature.

  13. Breket titanium (Titanium bracket

    Sianiwati Goenharto


    Full Text Available There has been a considerable discussion in the literature about corrosion and sensitivity to the nickel present in stainless steel brackets. Titanium has been heralded as a material totally compatible in the oral environment and superior in structural integrity compared to stainless steel. Many current applications in dentistry and medicine have made titanium an obvious choice for a possible substitute material. Titanium based brackets have shown excellent corrosion resistance and possessed good biocompatibility. Evaluation of titanium brackets for orthodontic therapy showed that titanium brackets were comparable to stainless steel brackets in passive and active configuration. Study about metallographic structure, hardness, bond strength to enamel substrate, etc. showed that titanium brackets exhibited a potential for clinical application. It was concluded that titanium brackets were suitable substitute for stainless steel brackets.

  14. Mechanical properties of coated titanium Beta-21S after exposure to air at 700 and 800 C

    Wiedemann, Karl E.; Bird, R. Keith; Wallace, Terryl A.; Clark, Ronald K.


    Mechanical properties of Beta-21S (Ti-15Mo-3Al-2.7Nb-0.2Si, wt percent) with glass, aluminide, and glass-on-aluminide coatings less than 3-micron thick were studied. Coatings were deposited by sol-gel processing or electron-beam evaporation onto 4.5-mil (113-micron) thick Beta-21S sheet from which, after oxidizing in air at 700 or 800 C, tensile test specimens were machined. Plastic elongation was the most severely degraded of the tensile properties; the glass-on-aluminide coatings were the most effective in preventing degradation. It was found that oxygen trapping by forming oxides in the coating, and reactions between the coatings and the Beta-21S alloy played significant roles.

  15. Laser Hardening of Metals

    Institute for Laser Physics; V.A.Serebryakov; K.V.Gratzianov; A.S.Eremenko; A.A.Timopheev; SPBSUITMO; M.V.Volkov


    Results of experiments on laser hardening of various materials with intensity 109~1010W/cm2 are represented. Nd:glass laser with energy up to 45J with a pulse duration ~30ns was used as a source of ra diation. Comparative researches of the laser peening for the various target areas are fulfilled. Results of laser hardening were determined by the microstructure analysis. The new approach to creation of the industrial laser for peening is discussed.

  16. Nucleation of cracks from shear-induced cavities in an {alpha}/{beta} titanium alloy in fatigue, room-temperature creep and dwell-fatigue

    Lefranc, P. [LMPM, UMR CNRS 6617, ENSMA, 86961 Futuroscope, Chasseneuil Cedex (France); LMS, UMR CNRS 7649, Ecole Polytechnique, 91128 Palaiseau Cedex (France); SNECMA Groupe SAFRAN, 77550 Moissy Cramayel (France); Doquet, V. [LMS, UMR CNRS 7649, Ecole Polytechnique, 91128 Palaiseau Cedex (France)], E-mail:; Gerland, M.; Sarrazin-Baudoux, C. [LMPM, UMR CNRS 6617, ENSMA, 86961 Futuroscope, Chasseneuil Cedex (France)


    In titanium alloys, dwell periods during room-temperature stress-controlled fatigue tests are responsible for substantial reductions in lifetime compared to pure fatigue loading. The mechanisms of such a creep-fatigue interaction have been investigated for alloy Ti-6242. Scanning and transmission electron microscopy observations revealed crack initiation by coalescence of shear-induced cavities nucleated at {alpha}/{beta} interfaces in large colonies of {alpha} laths nearly parallel to the loading axis. The density and average size of cavities were larger in dwell-fatigue and creep than in fatigue. A qualitative micromechanical model of cavity nucleation based on discrete dislocation dynamics was developed. The number of cycles for cavity nucleation was computed as a function of the applied stress range. A finite threshold, dependent on the size of {alpha} laths colonies with similar orientation, was found. The simulations predict earlier cavity nucleation in creep or dwell-fatigue than in pure fatigue, which is consistent with the performed experiments.

  17. Hardening Azure applications

    Gaurav, Suraj


    Learn what it takes to build large scale, mission critical applications -hardened applications- on the Azure cloud platform. This 208 page book covers the techniques and engineering principles that every architect and developer needs to know to harden their Azure/.NET applications to ensure maximum reliability and high availability when deployed at scale. While the techniques are implemented in .NET and optimized for Azure, the principles here will also be valuable for users of other cloud-based development platforms. Applications come in a variety of forms, from simple apps that can be bui

  18. Beta-钛与镍钛、不锈钢正畸弓丝合金成分、表面形貌以及力学性能的对比研究%A comparison study of elemental components, surface characteristics and mechanical properties of beta-titanium alloy wires, nitinol wires and stainless steel wires

    李兴; 杨凯; 张颖; 尤力; 宋西平


    目的:比较Beta-钛丝与正畸临床常用的超弹性镍钛丝及不锈钢丝的合金成分、表面形貌以及力学性能,为临床应用提供参考.方法:选取Beta-钛丝、超弹性镍钛丝及不锈钢丝,弓丝尺寸均为0.43 mm×0.64 mm.选用EDAX X-射线能谱分析仪联合SUPRATM 55热场发射扫描电子显微镜分析弓丝的合金成分,观察其表面形貌.使用Nano Indenter XP纳米压痕测试机测定弓丝弹性模量及硬度,使用Instron 5848微力材料试验机,三点弯曲测定弓丝的负荷-形变曲线.结果:Beta-钛丝合金成分中含有Ti、Zr、Mo、Sn 4种元素,不锈钢丝含有Fe、Mn、Cr、Si,超弹性镍钛丝含有Ni、Ti 2种元素.不锈钢丝表面比Beta-钛丝及镍钛丝光滑.Beta-钛丝的弹性模量及硬度明显小于不锈钢丝,略大于超弹性镍钛丝.当形变3 mm的负荷完全去除时,Beta-钛丝及不锈钢丝均有残余形变,超弹性镍钛丝形变完全恢复.结论:Beta-钛丝、超弹性镍钛丝及不锈钢丝依据其性能适用于正畸治疗的不同阶段.%Objective:To compare the differences of Beta-titanium alloy wires, superelastic nitinol wires and stainless steel wires (SSW) in elemental components, surface characteristics and mechanical properties for clinical orthodontic use. Methods; Beta-titanium alloy wires, superelastic nitinol wires and SSW were used. All the wires were in the same size of 0.43 mm×0.64 mm. ED AX and SUPRATM 55 SEM were used to analyze the components and surface characteristics. Nano Indenter XP was used to test elasticity modulus and hardness of the wires. Three-Bending Test was performed to compare the mechanical properties in Instron 5848 equipment. Results: Ti, Zr, Mo, Sn were contained in Beta- titanium wire, Ni and Ti in superelstic nitinol wire, Fe, Mn, Cr and Si in SSW. The surface of SSW was the smoothest. The value of elasticity modulus and hardness in Beta-titanium was much lower than in SSW and a little higher than in superelastic

  19. Concrete, hardened: Self desiccation

    Hansen, Ernst Jan De Place; Hansen, Kurt Kielsgaard; Persson, Bertil


    The test method covers the determination of internal relative humidity (RH) in hardened concrete and cement mortar using RH instruments. The determination of RH is done on crushed samples of concrete or cement motar. This test method is only for measuring equipment which gives off or takes up...

  20. Structural changes in VT1-0 titanium induced by deformation during explosion welding

    Makarova, E. B.; Esikov, M. A.; Gontarenko, A. S.; Sameishcheva, T. S.


    The hardening of VT1-0 titanium is studied during the formation of a multilayer material by explosion welding. The structural transformations in titanium plates are analyzed by metallographic and electron-microscopic methods. The mechanical properties of the welded multilayer titanium stacks are estimated using static and dynamic mechanical tests.

  1. Effect of Thymosin beta4 on the Differentiation and Mineralization of MC3T3-E1 Cell on a Titanium Surface.

    Jeong, Soon-Jeong; Jeong, Moon-Jin


    Osteoblasts are responsible for the synthesis of bone matrix through the secretion of collagenous and non-collagenous proteins with mineralization. Thymosin beta4 (Tbeta4) is an actin-sequestering peptide that is involved in the regulation of cell proliferation, differentiation and motility. A recent study reported that the inhibition of Tbeta4 mRNA synthesis strongly decreases the level of gene expression of bone sialoprotein (BSP), dentin sialophosphoprotein (DSPP), osteocalcin (OCN), osteonectin (ON) and collagen type I (Col I) with mineralization during differentiation in odontoblasts. Titanium (Ti) is used commonly as an implant material for dental implants, which have strong mechanical potential and good biocompatibility with bone. This study examined whether Tbeta4 can be a potential molecule for promoting the differentiation and mineralization of MC3T3-E1 cells on a Ti surface. Tbeta4 increased the viability of MC3T3-E1 cells during differentiation on Ti discs compared to that of the control. The expression of Tbeta4 mRNA and protein in the Tbeta4-treated MC3T3-E1 cells was higher than the control during differentiation on the Ti discs. In addition, Tbeta4 increased the formation of mineralization nodules and the mRNA expression of alkaline phosphatase (ALP), DSPP, dentin matrix protein1 (DMP1), BSP and Col I compared to that of the control in MC3T3-E1 cells during differentiation on Ti discs. From the results, Tbeta4 increased the viability and promoted the differentiation and mineralization of MC3T3-E1 cells on Ti discs. This highlights the potential use of Tbeta4 for increasing osseointegration through osteoblast differentiation and mineralization on Ti discs.

  2. RHOBOT: Radiation hardened robotics

    Bennett, P.C.; Posey, L.D. [Sandia National Labs., Albuquerque, NM (United States)


    A survey of robotic applications in radioactive environments has been conducted, and analysis of robotic system components and their response to the varying types and strengths of radiation has been completed. Two specific robotic systems for accident recovery and nuclear fuel movement have been analyzed in detail for radiation hardness. Finally, a general design approach for radiation-hardened robotics systems has been developed and is presented. This report completes this project which was funded under the Laboratory Directed Research and Development program.

  3. Grind hardening process

    Salonitis, Konstantinos


    This book presents the grind-hardening process and the main studies published since it was introduced in 1990s.  The modelling of the various aspects of the process, such as the process forces, temperature profile developed, hardness profiles, residual stresses etc. are described in detail. The book is of interest to the research community working with mathematical modeling and optimization of manufacturing processes.

  4. Alveolar macrophages stimulated with titanium dioxide, chrysotile asbestos, and residual oil fly ash upregulate the PDGF receptor-alpha on lung fibroblasts through an IL-1beta-dependent mechanism.

    Lindroos, P M; Coin, P G; Badgett, A; Morgan, D L; Bonner, J C


    Enhanced proliferation of fibroblasts is a primary characteristic of lung fibrosis. Macrophage-secreted platelet-derived growth factor (PDGF) is a potent mitogen and chemoattractant for lung fibroblasts. The magnitude of the fibroblast PDGF response is dependent on the number of PDGF receptor alpha (PDGF-R alpha) relative to PDGF-R beta at the cell surface. We recently reported that upregulation of the PDGF-R alpha subtype by interleukin (IL)-1beta results in enhanced lung fibroblast proliferation in response to PDGF-AA, PDGF-AB, and PDGF-BB whereas transforming growth factor (TGF)-beta1 has the opposite effect. Both IL-1beta and TGF-beta1 are produced by particle-activated macrophages in vivo and in vitro. We studied the net effect of macrophage conditioned medium (MOCM), which contains both IL-1beta and TGF-beta1, on the expression of the lung fibroblast PDGF receptor system. MOCM obtained from unstimulated, titanium dioxide (TiO2)-, chrysotile asbestos-, or residual oil fly ash (ROFA)-exposed macrophages in vitro increased [125I]PDGF-AA binding 3-, 6-, 6-, and 20-fold, respectively. These increases correlated with increased PDGF-R alpha mRNA and protein expression as shown by northern and western assays. PDGF-AB and -BB-stimulated [3H]thymidine incorporation by fibroblasts was enhanced 5-, 5-, 10-, and 20-fold by pretreatment with MOCM from unstimulated, TiO2-, asbestos-, and ROFA-exposed macrophages, respectively. [125I]PDGF-AA binding experiments using the IL-1 receptor antagonist blocked the upregulatory effect of all MOCM samples. Latent TGF-beta1 present in MOCM was activated by acid treatment, inhibiting upregulation by approximately 60%, a result similar to experiments with IL-1beta and TGF-beta1 mixtures. Treatment with a TGF-beta neutralizing antibody restored full upregulatory activity to acidified MOCM. Thus activated macrophages increase lung fibroblast PDGF-R alpha primarily due to the secretion of IL-1beta. Intratracheal instillation of ROFA

  5. Nuclear effects hardened shelters

    Lindke, Paul


    The Houston Fearless 76 Government Projects Group has been actively engaged for more than twenty-five years as a sub-contractor and currently as a prime contractor in the design, manufacture, repair and logistics support of custom mobile ground stations and their equipment accommodations. Other associated products include environmental control units (ECU's), mobilizers for shelters and a variety of mobile power generation units (MPU's). Since 1984, Houston Fearless 76 has designed and manufactured four 8' x 8' x 22' nuclear hardened mobile shelters. These shelters were designed to contain electronic data processing/reduction equipment. One shelter is currently being operated by the Air Force as a Defense Intelligence Agency (DIA) approved and certified Special Corrpartmented Information Facility (SCIF). During the development and manufacturing process of the shelters, we received continual technical assistance and design concept evaluations from Science Applications International Corporation (SAIC) Operations Analysis and Logistics Engineering Division and the Nondestructive Inspection Lab at McClellan AFB. SAIC was originally employed by the Air Force to design the nuclear hardening specifications applied to these shelters. The specific levels of hardening to which the shelters were designed are classified and will not be mentioned during this presentation.

  6. Industrial Hardening Demonstration.


    less severe conditions than thermal cracking (850’ - 950°F and 10 to 20 psi). Zeolitic or molecular sieve- base catalysts are used. Catalytic reforming...with Potential Industrial Hardening A-1 Participants B Post-Attack Petroleum Refining (and Production) B-1 from Crude Oil V List of Figures Number Page...the Key Worker Shelter 116 viii B-1 Proportions of the Products Obtained by Distillation B-2 of Six Crude Oils B-2 Generalized Flow Chart of the

  7. Nanodispersed boriding of titanium alloy

    Kateryna O. Kostyk


    Full Text Available The problem of improving the operational reliability of machines is becoming increasingly important due to the increased mechanical, thermal and other loads on the details. There are many surface hardening methods for machines parts which breakdown begins with surface corruption. The most promising methods are chemo-thermal treatment. Aim: The aim of this work is to study the impact of boriding on the structure and properties of titanium alloy. Materials and Methods: The material of this study is VT3-1 titanium alloy. The boriding were conducted using nanodispersed powder blend based on boric substances. Results: It is established that boriding of paste compounds allows obtaining the surface hardness within 30...29 GPa and with declining to 27...26 GPa in layer to the transition zone (with total thickness up to 110 μm owing to changes of the layer phase composition where Ti2B, TiB, TiB2 titanium borides are formed. The increasing of chemical-thermal treatment time from 15 minutes to 2 hours leads to thickening of the borated layer (30...110 µm and transition zone (30...190 µm. Conclusions: Due to usage of nanodispersed boric powder, the boriding duration is decreasing in 2...3 times. This allows saving time and electric energy. The developed optimal mode of boriding the VT3-1 titanium alloy allows obtaining the required operational characteristics and to combine the saturation of the surface layer with atomic boron and hardening.

  8. Cosmic Ray Helium Hardening

    Ohira, Yutaka


    Recent observations by CREAM, ATIC-2 and PAMELA experiments suggest that (1) the spectrum of cosmic ray (CR) helium is harder than that of CR proton below the knee $10^15 eV$ and (2) all CR spectra become hard at $\\gtrsim 10^{11} eV/n$. We propose a new picture that higher energy CRs are generated in more helium-rich region to explain the hardening (1) without introducing different sources for CR helium. The helium to proton ratio at $\\sim 100$ TeV exceeds the Big Bang abundance $Y=0.25$ by several times, and the different spectrum is not reproduced within the diffusive shock acceleration theory. We argue that CRs are produced in the chemically enriched region, such as a superbubble, and the outward-decreasing abundance naturally leads to the hard spectrum of CR helium when escaping from the supernova remnant (SNR) shock. We provide a simple analytical spectrum that also fits well the hardening (2) because of the decreasing Mach number in the hot superbubble with $\\sim 10^6$ K. Our model predicts hard and con...

  9. Evaluation of Strain Hardening Parameters

    DING Zong-hai; Pavel Huml; YANG Wei


    The plane-strain compression test for three kinds of materials was carried out in a temperature range between room temperature and 400 ℃. The σ - ε curves and strain-hardening rate at different temperatures were simulated and a reasonable fit to the experimental data was obtained. A modified model created by data inference and computer simulation was developed to describe the strain hardening at a large deformation, and the predicted strain hardening are in a good agreement with that observed in a large range of stress. The influences of different parameters on strain hardening behaviour under large deformation were analysed. The temperature increase within the test temperatures for stainless steel 18/8 Ti results in dropping of flow stress and strain-hardening rate. For favourable γ-fibre texture to obtain high r, the cold rolling was applied at large reduction. In the experimental procedure, the X-ray diffraction test was carried out to compare the strain hardening and microstructure under large deformation for a bcc steel (low carbon steel SS-1142). The results indicate that the high strain-hardening rate possibly occurs when the primary slip plane {110} is parallel to the rolling plane and the strain-hardening rate decreases when lots of {110} plane rotate out from the orientation {110}∥RP.

  10. On the modelling of strength differential and anisotropy exhibited by titanium

    Manopulo, Niko; Raemy, Christian; Hora, Pavel


    Modelling the response of titanium alloys under plastic deformation is challenging. In addition to strong anisotropy, these materials exhibit tension-compression asymmetry as well as anisotropic hardening even under monotonous loading conditions. The present contribution aims to propose a new modelling approach for titanium materials, by a homogeneous introduction of asymmetry into existing symmetric yield functions. Furthermore, anisotropic hardening effects are tracked describing the strain dependant yield surface evolution. The results are validated using the earing profile of deep drawn cups.

  11. Formation and evolution of the hardening precipitates in a Mg-Y-Nd alloy

    Barucca, G. [Dipartimento di Fisica e Ingegneria dei Materiali e del Territorio, Universita Politecnica delle Marche, Via Brecce Bianche, I-60131 Ancona (Italy); Ferragut, R. [Dipartimento di Fisica, LNESS and CNISM, Politecnico di Milano, Via Anzani 42, I-22100 Como (Italy); Fiori, F. [Dipartimento SAIFET, Sezione di Scienze Fisiche, Universita Politecnica delle Marche, Via Brecce Bianche, I-60131 Ancona (Italy); Lussana, D. [Dipartimento di Chimica IFM and NIS Centre, Universita di Torino, Via P. Giuria 9, I-10125 Torino (Italy); Mengucci, P., E-mail: [Dipartimento di Fisica e Ingegneria dei Materiali e del Territorio, Universita Politecnica delle Marche, Via Brecce Bianche, I-60131 Ancona (Italy); Moia, F. [Dipartimento di Fisica, LNESS and CNISM, Politecnico di Milano, Via Anzani 42, I-22100 Como (Italy); Riontino, G. [Dipartimento di Chimica IFM and NIS Centre, Universita di Torino, Via P. Giuria 9, I-10125 Torino (Italy)


    The formation and evolution of hardening precipitates in a Mg-Y-Nd (WE43) alloy during artificial ageing at 150 and 210 deg. C is followed by small angle X-ray scattering (SAXS) measurements, Vickers microhardness tests and transmission electron microscopy (TEM) observations. A quantitative description of the alloy studied during the early and advanced stages of the precipitation sequence is presented. In situ SAXS evolution at 210 deg. C of the size, volume fraction and number density of the subnanometer and nanometer particles that evolve in the {beta}'' phase was obtained. TEM and microhardness results indicate that the hardening mechanism is based on {beta}'' transformation of pre-precipitates and their growth at 150 deg. C, while at 210 deg. C hardening is mainly associated with {beta}'' {yields} {beta}' transformation.

  12. System-Level Radiation Hardening

    Ladbury, Ray


    Although system-level radiation hardening can enable the use of high-performance components and enhance the capabilities of a spacecraft, hardening techniques can be costly and can compromise the very performance designers sought from the high-performance components. Moreover, such techniques often result in a complicated design, especially if several complex commercial microcircuits are used, each posing its own hardening challenges. The latter risk is particularly acute for Commercial-Off-The-Shelf components since high-performance parts (e.g. double-data-rate synchronous dynamic random access memories - DDR SDRAMs) may require other high-performance commercial parts (e.g. processors) to support their operation. For these reasons, it is essential that system-level radiation hardening be a coordinated effort, from setting requirements through testing up to and including validation.

  13. Electrowinning molten titanium from titanium dioxide

    Van Vuuren, DS


    Full Text Available ; the high affinity of titanium for carbon, oxygen, and nitrogen; and physical and chemical properties of the different titanium oxide species when reducing titanium from Ti4+ to metallic titanium....

  14. Development of a Press-Hardened Steel Suitable for Thin Slab Direct Rolling Processing

    Lee, Jewoong; De Cooman, Bruno C.


    The thin slab casting and direct rolling process is a hot-rolled strip production method which has maintained commercial quality steel grades as a major material in many industrial applications due to its low processing cost. Few innovative products have however been developed specifically for production by thin slab direct rolling. Press hardening or hot press forming steel grades which are now widely used to produce structural automotive steel parts requiring ultra-high strength and formability may however offer an opportunity for thin slab direct rolling-specific ultra-high strength products. In this work, a newly designed press hardening steel grade developed specifically for thin slab direct rolling processing is presented. The press hardening steel has a high nitrogen content compared with press hardening steel grades produced by conventional steelmaking routes. Boron and titanium which are key alloying additions in conventional press hardening steel such as the 22MnB5 press hardening steel grade are not utilized. Cr is added in the press hardening steel to obtain the required hardenability. The properties of the new thin slab direct rolling-specific 22MnCrN5 press hardening steel grade are reviewed. The evolution of the microstructure and mechanical properties with increasing amounts of Cr additions from 0.6 to 1.4 wt pct and the effect of the cooling rate during die-quenching were studied by means of laboratory simulations. The selection of the optimum chemical composition range for the thin slab direct rolling-specific 22MnCrN5 steel in press hardening heat treatment conditions is discussed.

  15. Contact allergy to epoxy hardeners.

    Aalto-Korte, Kristiina; Suuronen, Katri; Kuuliala, Outi; Henriks-Eckerman, Maj-Len; Jolanki, Riitta


    Diglycidylether of bisphenol A resin is the most important sensitizer in epoxy systems, but a minority of patients develop concomitant or solitary contact allergy to epoxy hardeners. At the Finnish Institute of Occupational Health, several in-house test substances of epoxy hardeners have been tested in a special epoxy compound patch test series. To analyse the frequency and clinical relevance of allergic reactions to different epoxy hardeners. Test files (January 1991 to March 2013) were screened for contact allergy to different epoxy hardeners, and the clinical records of patients with allergic reactions were analysed for occupation, concomitant allergic reactions, and exposure. The most commonly positive epoxy hardeners were m-xylylenediamine (n = 24), 2,4,6-tris-(dimethylaminomethyl)phenol (tris-DMP; n = 14), isophorone-diamine (n = 12), and diethylenetriamine (n = 9). Trimethylhexamethylenediamine (n = 7), tetraethylenepentamine (n = 4), and triethylenetetramine (n = 2) elicited some reactions, although most patients were found to have no specific exposure. Allergic reactions to hexamethylenetetramine, dimethylaminopropylamine and ethylenediamine dihydrochloride were not related to epoxy products. Tris-DMP is an important sensitizer in epoxy hardeners, and should be included in the patch test series of epoxy chemicals. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.


    V. N. Fedulov


    Full Text Available The methods, enabing to produce the comparative appraisal of the titanium alloy ability to harden as a result of high-temperature thermal-mechanical processing depending on temperature and rate of deformation at forging, is developed.

  17. Surface hardening of titanium alloys by oxygen-diffusion-permeation

    马红岩; 王茂才; 张松; 辛公春; 魏政


    The surface oxygen-diffusion-permeation behaviors of Ti based alloys were investigated. MEF4A opticalmicroscopy and HMV-2000 micro-hardness tester were employed to characterize the microstructure and micro-hard-ness of the oxygen-permeated alloys. The results show that the micro-hardness of Ti based alloys are sharply en-hanced by the permeation of oxygen. The microstructure and micro-hardness of oxygen-permeated layer are stronglyrelated to the oxygen-diffusion-permeation techniques. The solid solution of oxygen in α phase can improve thetransformation temperature from α phase to β phase and enlarge the region of α phase so as to improve the micro-hardness of surface layer. Therefore, surface oxygen-diffusion-permeation would be a feasible method to reinforce Tibased alloys based on the solid solution of oxygen in α-Ti. At last, a diffusion-solution model was put forward.

  18. Micromilling experiments on hardened tool steel and Titanium

    Bissacco, Giuliano

    This document is an organized collection of the final settings, decisions, variations and relevant notes regarding the experimental work carried on at Pinol A/S by Giuliano Bissacco within the Ph.D. project Surface Generation and Optimization in Micromilling. The document is divided into sections...

  19. Compaction of Titanium Powders

    Gerdemann, Stephen,J; Jablonski, Paul, J


    Accurate modeling of powder densification has been an area of active research for more than 60 years. The earliest efforts were focused on linearization of the data because computers were not readily available to assist with curve-fitting methods. In this work, eight different titanium powders (three different sizes of sponge fines<150 {micro}m,<75 {micro}m, and<45 {micro}m; two different sizes of a hydride-dehydride [HDH]<75 {micro}m and<45 {micro}m; an atomized powder; a commercially pure [CP] Ti powder from International Titanium Powder [ITP]; and a Ti 6 4 alloy powder) were cold pressed in a single-acting die instrumented to collect stress and deformation data during compaction. From these data, the density of each compact was calculated and then plotted as a function of pressure. The results show that densification of all the powders, regardless of particle size, shape, or chemistry, can be modeled accurately as the sum of an initial density plus the sum of a rearrangement term and a work-hardening term. These last two terms are found to be a function of applied pressure and take the form of an exponential rise.

  20. Interfacial oxidations of pure titanium and titanium alloys with investments.

    Ban, S; Watanabe, T; Mizutani, N; Fukui, H; Hasegawa, J; Nakamura, H


    External oxides of a commercially pure titanium (cpTi), Ti6Al4V alloy, and an experimental beta-type titanium alloy (Ti 53.4 wt%, Nb 29 wt%, Ta 13 wt%, and Zr 4.6 wt%) were characterized after heating to 600, 900, 1150, and 1400 degrees C in contact with three types of investments (alumina cement, magnesia cement, and phosphate-bonded) in air. XRD studies demonstrated that MgO, Li2TiO3 and/or Li2Ti3O7 were formed through reactions with the metal and the constituents in the magnesia cement-investment after heating to 900, 1150, and 1400 degrees C. Except for these conditions, TiO2 (rutile) was only formed on cpTi. For titanium alloys, the other components apart from Ti also formed simple and complex oxides such as Al2O3 and Al2TiO5 on Ti6Al4V, and Zr0.25Ti0.75Nb2O7 on the beta-type titanium alloy. However, no oxides containing V or Ta were formed. These results suggest that the constituents of titanium alloys reacted with the investment oxides and atmospheric oxygen to form external oxides due to the free energy of oxide formation and the concentration of each element on the metal surface.

  1. Multi-material linearization beam hardening correction for computed tomography.

    Lifton, J J


    Since beam hardening causes cupping and streaking artifacts in computed tomographic images, the presence of such artifacts can impair both qualitative and quantitative analysis of the reconstructed data. When the scanned object is composed of a single material, it is possible to correct beam hardening artifacts using the linearization method. However, for multi-material objects, an iterative segmentation-based correction algorithm is needed, which is not only computationally expensive, but may also fail if the initial segmentation result is poor. In this study, a new multi-material linearization beam hardening correction method was proposed and evaluated. The new method is fast and implemented in the same manner as a mono-material linearization. The correction takes approximately 0.02 seconds per projection. Although facing a potential disadvantage of requiring attenuation measurements of one of the object's constituent materials, applying the new method has demonstrated its capability for a multi-material workpiece with substantial reduction in both cupping and streaking artifacts. For example, the study showed that the absolute cupping artefacts in steel, titanium and aluminum spheres were reduced from 22%, 20% and 20% to 5%, 1% and 0%, respectively.

  2. Strain rate dependence of the flow stress and work hardening of single crystals of Ni{sub 3}(Al,Hf)B

    Ezz, S.S.; Sun, Y.Q.; Hirsch, P.B. [Univ. of Oxford (United Kingdom). Dept. of Materials


    The strain rate sensitivity {beta} of the flow stress {tau} is associated with work hardening and {beta} = ({delta}{tau}/{delta}ln {dot {var_epsilon}}) is proportional to the work hardening increment {tau}{sub h} = {tau} {minus} {tau}{sub y}, where {tau}{sub y} is the strain rate independent yield stress. The temperature dependence of {beta}/{tau}{sub h} reflects changes in the rate controlling mechanism. At intermediate and high temperatures, the hardening correlates with the density of [{bar 1}01] dislocations on (010). The nature of the local obstacles at room temperature is not established.

  3. Cold dynamic compaction of pre-alloyed titanium and activated sintering

    Raybould, D.


    The use of dynamic compaction has been found to allow the cold consolidation of Ti-6Al-4V to densities of 99% T.D. Although full interparticle welding was not attained, bonding was found to occur during a low temperature sintering operation; below the ..beta.. transition. The high strengths and toughness values thus obtained are due to an activation of the sintering operation caused by the removal of surface oxide and good metal to metal bonds formed during dynamic compaction, when extensive local shearing of the particles surface occurs. This activation of sintering allows a control of microstructure and in particular, avoidance of embrittling phases. During compaction the passage of the shock wave results in the formation of a shocked structure. Spherical powders usually compact dynamically to characteristic shapes. The shock hardening allows the particle through which the shock has passed to deform the subsequent particle it impacts. This is rarely observed with the titanium alloy, indicating the low shock hardening or high initial hardness of the powders. Areas of interparticle melting were observed, but appeared to be the melting of a third particle rather than melting and bonding between particles.


    Experiments were made to determine the most efficient method of strain hardening railroad frog points in order to increase their fatigue resistance...Mechanical strain hardening with rolls 40 mm in diameter under a load of 8 tons produced in standard frogs cast from G13L high-manganese steel (AISI...Hadfield steel) a work-hardened surface layer 3-5 mm thick with a hardness of 340 HB. In other experiments, the frogs were hardened by exploding a

  5. Onycholysis induced by nail hardener.

    Helsing, Per; Austad, Joar; Talberg, Hans Jørgen


    Nail hardeners appeared in the market during the 1960s. They were basically solutions of formaldehyde. The first adverse effects were published in 1966 (1). Reactions were onycholysis, chromonychia, subungual haemorrhage, and hyperkeratosis. Onycholysis may be non-inflammatory or inflammatory, and is accompanied by throbbing pain. Inflammatory reactions are followed by paronychia and occasional dermatitis on the digital pulpa.



    The mechanical properties and durability ( mainly frost-resistance and carbonation resistance ) of fly ash-CaO-CaSO4 .2H2O hardened paste are studied. The relationship among durability of harden ed fly ash paste, the quantity and distribution of hydrates and the initial p aste texture of hardened fly ash paste is presented.

  7. Reduction of metal artifacts: beam hardening and photon starvation effects

    Yadava, Girijesh K.; Pal, Debashish; Hsieh, Jiang


    The presence of metal-artifacts in CT imaging can obscure relevant anatomy and interfere with disease diagnosis. The cause and occurrence of metal-artifacts are primarily due to beam hardening, scatter, partial volume and photon starvation; however, the contribution to the artifacts from each of them depends on the type of hardware. A comparison of CT images obtained with different metallic hardware in various applications, along with acquisition and reconstruction parameters, helps understand methods for reducing or overcoming such artifacts. In this work, a metal beam hardening correction (BHC) and a projection-completion based metal artifact reduction (MAR) algorithms were developed, and applied on phantom and clinical CT scans with various metallic implants. Stainless-steel and Titanium were used to model and correct for metal beam hardening effect. In the MAR algorithm, the corrupted projection samples are replaced by the combination of original projections and in-painted data obtained by forward projecting a prior image. The data included spine fixation screws, hip-implants, dental-filling, and body extremity fixations, covering range of clinically used metal implants. Comparison of BHC and MAR on different metallic implants was used to characterize dominant source of the artifacts, and conceivable methods to overcome those. Results of the study indicate that beam hardening could be a dominant source of artifact in many spine and extremity fixations, whereas dental and hip implants could be dominant source of photon starvation. The BHC algorithm could significantly improve image quality in CT scans with metallic screws, whereas MAR algorithm could alleviate artifacts in hip-implants and dentalfillings.

  8. Low cost fabrication of sheet structure using a new beta titanium alloy, Ti-15V-3Cr-3Al-3Sn

    Kaneko, R. S.; Davis, G. W.; Woods, C. A.; Royster, D. M.


    Development efforts have been undertaken to improve the processing and structural efficiencies of advanced cold-formable beta Ti alloys, using the standard, hot-formed and rivetted construction of Ti-6Al-4V sheet structures as a basis for comparison. Ti-15V-3Cr-3Al-3Sn (Ti-15-3) beta alloy is formable, brazable and weldable in the solution-treated condition, and after aging displays mechanical properties suitable for postulated service in the -65 to 600 F temperature range. A novel methodology using cold-formed Ti-15-3 stringers and Ti-6Al-4V face sheets that are joined by means of an out-of-furnace isothermal brazing process, followed by low temperature aging, can reduce production costs by as much as 28 per cent. Structural efficiency has been demonstrated in room and elevated temperature crippling tests of small skin-stringer assemblies.

  9. Low cost fabrication of sheet structure using a new beta titanium alloy, Ti-15V-3Cr-3Al-3Sn

    Kaneko, R. S.; Davis, G. W.; Woods, C. A.; Royster, D. M.


    Development efforts have been undertaken to improve the processing and structural efficiencies of advanced cold-formable beta Ti alloys, using the standard, hot-formed and rivetted construction of Ti-6Al-4V sheet structures as a basis for comparison. Ti-15V-3Cr-3Al-3Sn (Ti-15-3) beta alloy is formable, brazable and weldable in the solution-treated condition, and after aging displays mechanical properties suitable for postulated service in the -65 to 600 F temperature range. A novel methodology using cold-formed Ti-15-3 stringers and Ti-6Al-4V face sheets that are joined by means of an out-of-furnace isothermal brazing process, followed by low temperature aging, can reduce production costs by as much as 28 per cent. Structural efficiency has been demonstrated in room and elevated temperature crippling tests of small skin-stringer assemblies.

  10. Determination and Analysis of Hardenability for Hot-Forging Die Steels with Deep-Hardening


    ERH end-quenching method was us ed to determine the hardenability of four kinds hot-forging die steels with dee p-hardening and hence the order of their hardenability was given. The tempering hardness of the steels was measured and the tempering resistance was studied. It was approved that ERH method is effective for the determination of hardenability of deep-hardening steel and the beginning of hardness drop in the ERH specimen is caused by bainite occurring.

  11. Titanium-Beta Zeolites Catalyze the Stereospecific Isomerization of D-Glucose to L-Sorbose via Intramolecular C5-C1 Hydride Shift

    Gounder, Rajamani [California Inst. of Technology (CalTech), Pasadena, CA (United States); Davis, Mark E. [California Inst. of Technology (CalTech), Pasadena, CA (United States)


    Pure-silica zeolite beta containing Lewis acidic framework Ti4+ centers (Ti-Beta) is shown to catalyze the isomerization of D-glucose to L-sorbose via an intramolecular C5–C1 hydride shift. Glucose–sorbose isomerization occurs in parallel to glucose–fructose isomerization on Ti-Beta in both water and methanol solvents, with fructose formed as the predominant product in water and sorbose as the predominant product in methanol (at 373 K) at initial times and over the course of >10 turnovers. Isotopic tracer studies demonstrate that 13C and D labels placed respectively at the C1 and C2 positions of glucose are retained respectively at the C6 and C5 positions of sorbose, consistent with its formation via an intramolecular C5–C1 hydride shift isomerization mechanism. This direct Lewis acid-mediated pathway for glucose–sorbose isomerization appears to be unprecedented among heterogeneous or biological catalysts and sharply contrasts indirect base-mediated glucose–sorbose isomerization via 3,4-enediol intermediates or via retro-aldol fragmentation and recombination of sugar fragments. Measured first-order glucose–sorbose isomerization rate constants (per total Ti; 373 K) for Ti-Beta in methanol are similar for glucose and glucose deuterated at the C2 position (within a factor of ~1.1), but are a factor of ~2.3 lower for glucose deuterated at each carbon position, leading to H/D kinetic isotope effects expected for kinetically relevant intramolecular C5–C1 hydride shift steps. Optical rotation measurements show that isomerization of D-(+)-glucose (92% enantiomeric purity) with Ti-Beta in water (373 K) led to the formation of L-(-)-sorbose (73% enantiomeric purity) and D-(-)-fructose (87% enantiomeric purity) as the predominant stereoisomers, indicating that stereochemistry is preserved at carbon centers not directly involved in intramolecular C5–C1 or C2–C1 hydride shift steps, respectively. This new Lewis acid

  12. Surface Fatigue Resistance with Induction Hardening

    Townsend, Dennis; Turza, Alan; Chapman, Mike


    Induction hardening has been used for some years to harden the surface and improve the strength and service life of gears and other components. Many applications that employ induction hardening require a relatively long time to finish the hardening process and controlling the hardness of the surface layer and its depth often was a problem. Other surface hardening methods, ie., carbonizing, take a very long time and tend to cause deformations of the toothing, whose elimination requires supplementary finishing work. In double-frequency induction hardening, one uses a low frequency for the preheating of the toothed wheel and a much higher frequency for the purpose of rapidly heating the surface by way of surface hardening.

  13. Energetic model of metal hardening

    Ignatova O.N.


    Full Text Available Based on Bailey hypothesis on the link between strain hardening and elastic lattice defect energy this paper suggests a shear strength energetic model that takes into consideration plastic strain intensity and rate as well as softening related to temperature annealing and dislocation annihilation. Metal strain hardening was demonstrated to be determined only by elastic strain energy related to the energy of accumulated defects. It is anticipated that accumulation of the elastic energy of defects is governed by plastic work. The suggested model has a reasonable agreement with the available experimental data for copper up to P = 70 GPa , for aluminum up to P = 10 GPa and for tantalum up to P = 20 GPa.

  14. Scintillation-Hardened GPS Receiver

    Stephens, Donald R.


    CommLargo, Inc., has developed a scintillation-hardened Global Positioning System (GPS) receiver that improves reliability for low-orbit missions and complies with NASA's Space Telecommunications Radio System (STRS) architecture standards. A software-defined radio (SDR) implementation allows a single hardware element to function as either a conventional radio or as a GPS receiver, providing backup and redundancy for platforms such as the International Space Station (ISS) and high-value remote sensing platforms. The innovation's flexible SDR implementation reduces cost, weight, and power requirements. Scintillation hardening improves mission reliability and variability. In Phase I, CommLargo refactored an open-source GPS software package with Kalman filter-based tracking loops to improve performance during scintillation and also demonstrated improved navigation during a geomagnetic storm. In Phase II, the company generated a new field-programmable gate array (FPGA)-based GPS waveform to demonstrate on NASA's Space Communication and Navigation (SCaN) test bed.

  15. Titanium Alloys

    Mark T. Whittaker


    Full Text Available Although originally discovered in the 18th century [1], the titanium industry did not experience any significant advancement until the middle of the 20th century through the development of the gas turbine engine [2]. Since then, the aerospace sector has dominated worldwide titanium use with applications in both engines and airframe structures [3]. The highly desirable combination of properties, which include excellent corrosion resistance, favourable strength to weight ratios, and an impressive resistance to fatigue, has led to an extensive range of applications [4], with only high extraction and processing costs still restricting further implementation. [...

  16. Titanium Alloys and Processing for High Speed Aircraft

    Brewer, William D.; Bird, R. Keith; Wallace, Terryl A.


    Commercially available titanium alloys as well as emerging titanium alloys with limited or no production experience are being considered for a variety of applications to high speed commercial aircraft structures. A number of government and industry programs are underway to improve the performance of promising alloys by chemistry and/or processing modifications and to identify appropriate alloys and processes for specific aircraft structural applications. This paper discusses some of the results on the effects of heat treatment, service temperatures from - 54 C to +177 C, and selected processing on the mechanical properties of several candidate beta and alpha-beta titanium alloys. Included are beta alloys Timetal 21S, LCB, Beta C, Beta CEZ, and Ti-10-2-3 and alpha-beta alloys Ti-62222, Ti-6242S, Timetal 550, Ti-62S, SP-700, and Corona-X. The emphasis is on properties of rolled sheet product form and on the superplastic properties and processing of the materials.

  17. Determination of the macroscopic elastic constants of a phase embedded in a multiphase polycrystal-application to the {beta}-phase of a Ti-17 titanium based alloy

    Freour, S.; Gloaguen, D.; Guillen, R.; Girard, E. [Lab. d' Applications des Materiaux a la Mecanique (LAMM), L.A.M.M. - C.R.T.T., Saint Nazaire (France); Francois, M. [Lab. des Systemes Mecaniques et d' Ingenierie Simultanee (LASMIS), Univ. De Technologie de Troyes, Troyes (France); Bouillo, J. [Dept. Genie Civil - IUT de Saint Nazaire (France)


    A one-site elastic self-consistent model following the mathematical formalism introduced by Kroener and Eshelby (KE) has been developed in order to solve the case of multiphase materials. This model has been applied to duplex steels and aluminium - silicium carbide metal matrix composites (MMC) in the aim to study the evolution of their stiffness at pseudomacroscopic scale. Simulations justify the usually implicit hypothesis of the identity of the elastic moduli of a given phase, at macroscopic and pseudomacroscopic scales. The implementation of KE model by this hypothesis yields a new implicit formulation for the stiffness of a given unknown phase embedded in a two-phases material. This original characterization method will be applied to the {beta}-phase of Ti-17 alloy. The singular behaviour in terms of residual pseudomacrostress of each phase after uniaxial loadings will be deduced from these data. (orig.)

  18. Radiation Hardened Electronics for Extreme Environments

    Keys, Andrew S.; Watson, Michael D.


    The Radiation Hardened Electronics for Space Environments (RHESE) project consists of a series of tasks designed to develop and mature a broad spectrum of radiation hardened and low temperature electronics technologies. Three approaches are being taken to address radiation hardening: improved material hardness, design techniques to improve radiation tolerance, and software methods to improve radiation tolerance. Within these approaches various technology products are being addressed including Field Programmable Gate Arrays (FPGA), Field Programmable Analog Arrays (FPAA), MEMS Serial Processors, Reconfigurable Processors, and Parallel Processors. In addition to radiation hardening, low temperature extremes are addressed with a focus on material and design approaches.

  19. Simultaneous surface engineering and bulk hardening of precipitation hardening stainless steel

    Frandsen, Rasmus Berg; Christiansen, Thomas; Somers, Marcel A. J.


    This article addresses simultaneous bulk precipitation hardening and low temperature surface engineering of two commercial precipitation hardening stainless steels: Sandvik Nanoflex® and Uddeholm Corrax®. Surface engineering comprised gaseous nitriding or gaseous carburising. Microstructural....... The duration and temperature of the nitriding/carburising surface hardening treatment can be chosen in agreement with the thermal treatment for obtaining optimal bulk hardness in the precipitation hardening stainless steel....

  20. Increasing Wear Resistance of Titanium Alloys by Anode Plasma Electrolytic Saturation with Interstitial Elements

    Belkin, P. N.; Kusmanov, S. A.; Dyakov, I. G.; Silkin, S. A.; Smirnov, A. A.


    In our previous studies, we have shown that anode plasma electrolytic saturation of titanium alloys with nitrogen and carbon can improve their tribological properties. Obtained structure containing oxide layer and solid solution of diffused element in titanium promotes the enhancement of running-in ability and the decrease in the wear rate in some special cases. In this paper, further investigations are reported regarding the tribological properties of alpha- and beta-titanium alloys in wear test against hardened steel (50 HRC) disk using pin-on-disk geometry and balls of Al2O3 (6.25 mm in diameter) or bearing steel (9.6 mm in diameter) with ball-on-plate one and normal load from 5 to 209 N. Reproducible results were obtained under testing samples treated by means of the plasma electrolytic nitriding (PEN) with the mechanical removal of the oxide layer. Friction coefficient of nitrided samples is 0.5-0.9 which is somewhat higher than that for untreated one (0.48-0.75) during dry sliding against Al2O3 ball. An increase in the sliding speed results in the polishing of nitrided samples and reduction of their wear rate by 60 times. This result is obtained for 5 min at 850 °C using PEN in electrolyte containing 5 wt.% ammonia and 10 wt.% ammonium chloride followed by quenching in solution. Optical microscope was employed to assist in the evaluation of the wear behavior. Sizes of wear tracks were measured by profilometer TR200.

  1. Challenges in hardening technologies using shallow-trench isolation

    Shaneyfelt, M.R.; Dodd, P.E.; Draper, B.L.; Flores, R.S.


    Challenges related to radiation hardening CMOS technologies with shallow-trench isolation are explored. Results show that trench hardening can be more difficult than simply replacing the trench isolation oxide with a hardened field oxide.

  2. Deformation Wave Hardening of Metallic Materials

    A.V. Kirichek


    Full Text Available The article deals with the machine parts hardening by means of deformation waves generated by the impact system with a waveguide as an intermediary member. The conditions for the efficient use of impact energy for elastoplastic deformation of the processed material and creation of the deep hardened surface layer.

  3. Investigation of a Hardened Cement Paste Grout

    Esteves, Luis Pedro; Sørensen, Eigil Verner

    This report documents a series of tests performed on a hardened cement paste grout delivered by the client, Det Norske Veritas A/S.......This report documents a series of tests performed on a hardened cement paste grout delivered by the client, Det Norske Veritas A/S....

  4. Method of hardening a fluid mass

    Zitha, P.L.J.; Jansen, J.D.


    The invention relates to a method of hardening a fluid mass in contact with a wall, in a desirable shape. According to the invention, the fluid mass is a magneto-rheological fluid mixture that in addition to at least one hardening component comprises a particulate magnetic component, with minimally

  5. Method of hardening a fluid mass

    Zitha, P.L.J.; Jansen, J.D.


    The invention relates to a method of hardening a fluid mass in contact with a wall, in a desirable shape. According to the invention, the fluid mass is a magneto-rheological fluid mixture that in addition to at least one hardening component comprises a particulate magnetic component, with minimally

  6. Comparison of Thermal Creep Strain Calculation Results Using Time Hardening and Strain Hardening Rules

    Kim, Junehyung; Cheon, Jinsik; Lee, Byoungoon; Lee, Chanbock [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)


    One of the design criteria for the fuel rod in PGSFR is the thermal creep strain of the cladding, because the cladding is exposed to a high temperature for a long time during reactor operation period. In general, there are two kind of calculation scheme for thermal creep strain: time hardening and strain hardening rules. In this work, thermal creep strain calculation results for HT9 cladding by using time hardening and strain hardening rules are compared by employing KAERI's current metallic fuel performance analysis code, MACSIS. Also, thermal creep strain calculation results by using ANL's metallic fuel performance analysis code, LIFE-METAL which adopts strain hardening rule are compared with those by using MACSIS. Thermal creep strain calculation results for HT9 cladding by using time hardening and strain hardening rules were compared by employing KAERI's current metallic fuel performance analysis code, MACSIS. Also, thermal creep strain calculation results by using ANL's metallic fuel performance analysis code, LIFE-METAL which adopts strain hardening rule were compared with those by using MACSIS. Tertiary creep started earlier in time hardening rule than in strain hardening rule. Also, calculation results by MACSIS with strain hardening and those obtained by using LIFE-METAL were almost identical to each other.

  7. The influence of Glassex additive on properties of microwave-hardened and self- hardened moulding sands with water glass

    K. Major-Gabryś


    Full Text Available The article takes into consideration the researches concerning inserting the Glassex additive to the microwaved-hardened and self- hardened moulding sands with water glass. In the research different types of ester hardeners to self-hardened moulding sands with water glass were used. The influence of Glassex additive on retained strength of moulding sands with different hardeners and prepared by different technologies of hardening were tested. The influence of different hardeners and the technology of hardening on retained strength of moulding sand with water glass and the Glassex additive were also estimated.

  8. Opportunities in the electrowinning of molten titanium from titanium dioxide

    Van Vuuren, DS


    Full Text Available ; the high affinity of titanium for carbon, oxygen, and nitrogen; and physical and chemical properties of the different titanium oxide species when reducing titanium from Ti4+ to metallic titanium....

  9. Process for hardening the surface of polymers

    Mansur, Louis K.; Lee, Eal H.


    Hard surfaced polymers and the method for making them is generally described. Polymers are subjected to simultaneous multiple ion beam bombardment, that results in a hardening of the surface and improved wear resistance.

  10. Precipitation hardening in Fe--Ni base austenitic alloys

    Chang, K.M.


    The precipitation of metastable Ni/sub 3/X phases in the austenitic Fe--Ni-base alloys has been investigated by using various combinations of hardening elements, including Ti, Ta, Al, and Nb. The theoretical background on the formation of transition precipitates has been summarized based on: atomic size, compressibility, and electron/atom ratio. A model is proposed from an analysis of static concentration waves ordering the fcc lattice. Ordered structure of metastable precipitates will change from the triangularly ordered ..gamma..', to the rectangularly ordered ..gamma..'', as the atomic ratio (Ti + Al)/(Ta + Nb) decreases. The concurrent precipitation of ..gamma..' and ..gamma..'' occurs at 750/sup 0/C when the ratio is between 1.5 and 1.9. Aging behavior was studied over the temperature range of 500/sup 0/C to 900/sup 0/C. Typical hardness curves show a substantial hardening effect due to precipitation. A combination of strength and fracture toughness can be developed by employing double aging techniques. The growth of these coherent intermediate precipitates follows the power law with the aging time t : t/sup 1/3/ for the spherical ..gamma..' particles; and t/sup 1/2/ for the disc-shaped ..gamma..''. The equilibrium ..beta.. phase is observed to be able to nucleate on the surface of imbedded carbides. The addition of 5 wt % Cr to the age-hardened alloys provides a non-magnetic austenite which is stable against the formation of mechanically induced martensite.Cr addition retards aging kinetics of the precipitation reactions, and suppresses intergranular embrittlement caused by the high temperature solution anneal. The aging kinetics are also found to be influenced by solution annealing treatments.


    A. V. Kovalchuk


    Full Text Available The method of complex surface hardening of steel detailswas designed. The method is a compound of two processes of hardening: chemical heat treatment and physical vapor deposition (PVD of the coating. The result, achieved in this study is much higher, than in other work on this topic and is cumulative. The method designed can be used in mechanical engineering, medicine, energetics and is perspective for military and space technologies.

  12. Properties and Commercial Application of Manual Plasma Hardening

    Korotkov, V. A.


    A new method and a device for plasma hardening of various parts are considered. Installation of the new device does not require too much investment (the active mechanical productions are appropriate for its accommodation) and special choice of personnel (welders train to use it without difficulty). Plasma hardening does not deform and worsen the smoothness of the surface, which makes it possible to employ many hardened parts without finishing mechanical treatment required after bulk or induction hardening. The hardened layer (about 1 mm) produced by plasma hardening exhibits better wear resistance than after bulk hardening with tempering, which prolongs the service life of the parts.

  13. Infrared Camera Analysis of Laser Hardening

    J. Tesar


    Full Text Available The improvement of surface properties such as laser hardening becomes very important in present manufacturing. Resulting laser hardening depth and surface hardness can be affected by changes in optical properties of material surface, that is, by absorptivity that gives the ratio between absorbed energy and incident laser energy. The surface changes on tested sample of steel block were made by engraving laser with different scanning velocity and repetition frequency. During the laser hardening the process was observed by infrared (IR camera system that measures infrared radiation from the heated sample and depicts it in a form of temperature field. The images from the IR camera of the sample are shown, and maximal temperatures of all engraved areas are evaluated and compared. The surface hardness was measured, and the hardening depth was estimated from the measured hardness profile in the sample cross-section. The correlation between reached temperature, surface hardness, and hardening depth is shown. The highest and the lowest temperatures correspond to the lowest/highest hardness and the highest/lowest hardening depth.

  14. Bad Beta, Good Beta

    Campbell, John; Vuolteenaho, Tuomo


    This paper explains the size and value "anomalies" in stock returns using an economically motivated two-beta model. We break the beta of a stock with the market portfolio into two components, one reflecting news about the market's future cash flows and one reflecting news about the market's discount rates. Intertemporal asset pricing theory suggests that the former should have a higher price of risk; thus beta, like cholesterol, comes in "had" and "good" varieties. Empirically, we find that v...

  15. Titanium and titanium alloys fundamentals and applications

    Peters, Manfred


    This handbook is an excellent reference for materials scientists and engineers needing to gain more knowledge about these engineering materials. Following introductory chapters on the fundamental materials properties of titanium, readers will find comprehensive descriptions of the development, processing and properties of modern titanium alloys. There then follows detailed discussion of the applications of titanium and its alloys in aerospace, medicine, energy and automotive technology.

  16. Chinese titanium industry


    <正>The effects of the financial crisis on the titanium industry are visible: investment plans for titanium smelting and processing have basically come to a halt in 2009, and projects under construction were also delayed. However, the

  17. On Analytical Solutions to Beam-Hardening

    Rigaud, G.


    When polychromatic X-rays propagate through a material, for instance in computerized tomography (CT), low energy photons are more attenuated resulting in a "harder" beam. The beam-hardening phenomenon breaks the monochromatic radiation model based on the Radon transform giving rise to artifacts in CT reconstructions to the detriment of visual inspection and automated segmentation algorithms. We propose first a simplified analytic representation for the beam-hardening. Besides providing a general understanding of the phenomenon, this model proposes to invert the beam-hardening effect for homogeneous objects leading to classical monochromatic data. For heterogeneous objects, no analytical reconstruction of the density can be derived without more prior information. However, the beam-hardening is shown to be a smooth operation on the data and thus to preserve the encoding of the singularities of the attenuation map within the data. A microlocal analysis encourages the use of contour extraction methods to solve partially the beam-hardening effect even for heterogeneous objects. The application of both methods, exact analytical solution for homogeneous objects and feature extraction for heterogeneous ones, on real data demonstrates their relevancy and efficiency.

  18. Modeling of Irradiation Hardening of Polycrystalline Materials

    Li, Dongsheng; Zbib, Hussein M.; Garmestani, Hamid; Sun, Xin; Khaleel, Mohammad A.


    High energy particle irradiation of structural polycrystalline materials usually produces irradiation hardening and embrittlement. The development of predict capability for the influence of irradiation on mechanical behavior is very important in materials design for next generation reactors. In this work a multiscale approach was implemented to predict irradiation hardening of body centered cubic (bcc) alpha-iron. The effect of defect density, texture and grain boundary was investigated. In the microscale, dislocation dynamics models were used to predict the critical resolved shear stress from the evolution of local dislocation and defects. In the macroscale, a viscoplastic self-consistent model was applied to predict the irradiation hardening in samples with changes in texture and grain boundary. This multiscale modeling can guide performance evaluation of structural materials used in next generation nuclear reactors.

  19. An Anisotropic Hardening Model for Springback Prediction

    Zeng, Danielle; Xia, Z. Cedric


    As more Advanced High-Strength Steels (AHSS) are heavily used for automotive body structures and closures panels, accurate springback prediction for these components becomes more challenging because of their rapid hardening characteristics and ability to sustain even higher stresses. In this paper, a modified Mroz hardening model is proposed to capture realistic Bauschinger effect at reverse loading, such as when material passes through die radii or drawbead during sheet metal forming process. This model accounts for material anisotropic yield surface and nonlinear isotropic/kinematic hardening behavior. Material tension/compression test data are used to accurately represent Bauschinger effect. The effectiveness of the model is demonstrated by comparison of numerical and experimental springback results for a DP600 straight U-channel test.

  20. Induction surface hardening of hard coated steels

    Pantleon, Karen; Kessler, Olaf; Hoffmann, Franz


    -process is the high deposition temperature, consequently the properties of steel substrates are negatively influenced. Therefore, a subsequent heat treatment of the coated steels is necessary to restore the properties of steels ready for operation. Induction surface hardening is used as a method of heat treatment....... The effect of induction surface hardening on the properties of the coating-substrate-systems is mainly characterized using investigations of microstructure and chemical composition as well as measurements of hardness and residual stresses in dependence on the distance from the surface. Furthermore......, the scratch test is used to estimate critical loads for cohesive and adhesive failure of the coatings. Additionally, distortion measurements are carried out. The results emphasize the advantage of induction surface hardening as a method of subsequent heat treatment of CVD-coated steels....

  1. Titanium Carbide-Graphite Composites


    titanium carbide , titanium carbide with free graphite, titanium carbide /vanadium carbide alloy with free graphite, and titanium carbide with...from melts. The test pins were drawn across hot pressed titanium carbide wear plates with 5 newtons of normal force. The lowest friction coefficient at...22 C was 0.12 obtained with pure titanium carbide . The lowest friction coefficient at 900 C was 0.19 obtained with titanium carbide with boron and

  2. A novel radiation hardened by design latch

    Huang Zhengfeng; Liang Huaguo


    Due to aggressive technology scaling, radiation-induced soft errors have become a serious reliability concern in VLSI chip design. This paper presents a novel radiation hardened by design latch with high single-event-upset (SEU) immunity. The proposed latch can effectively mitigate SEU by internal dual interlocked scheme. The propagation delay, power dissipation and power delay product of the presented latch are evaluated by detailed SPICE simulations. Compared with previous SEU-hardening solutions such as TMR-Latch, the presented latch is more area efficient, delay and power efficient. Fault injection simulations also demonstrate the robustness of the presented latch even under high energy particle strikes.

  3. "Work-Hardenable" ductile bulk metallic glass.

    Das, Jayanta; Tang, Mei Bo; Kim, Ki Buem; Theissmann, Ralf; Baier, Falko; Wang, Wei Hua; Eckert, Jürgen


    Usually, monolithic bulk metallic glasses undergo inhomogeneous plastic deformation and exhibit poor ductility (< 1%) at room temperature. We present a new class of bulk metallic glass, which exhibits high strength of up to 2265 MPa together with extensive "work hardening" and large ductility of 18%. Significant increase in the flow stress was observed during deformation. The "work-hardening" capability and ductility of this class of metallic glass is attributed to a unique structure correlated with atomic-scale inhomogeneity, leading to an inherent capability of extensive shear band formation, interactions, and multiplication of shear bands.

  4. Radiation hardening revisited: Role of intracascade clustering

    Singh, B.N.; Foreman, A.J.E.; Trinkaus, H.


    be explained in terms of conventional dispersed-barrier hardening because (a) the grown-in dislocations are not free, and (b) irradiation-induced defect clusters are not rigid indestructible Orowan obstacles. A new model called 'cascade-induced source hardening' is presented where glissile loops produced...... directly in cascades are envisaged to decorate the grown-in dislocations so that they cannot act as dislocation sources. The upper yield stress is related to the breakaway stress which is necessary to pull the dislocation away from the clusters/loops decorating it. The magnitude of the breakaway stress has...

  5. Plasma Arc Surface Hardening Robot Technology


    In national economy and national defense, a lot of ma chine components become worthless early because of wear and tear and corrode. It leads to huge loss of resource and material. Surface hardening of the steel cou ld form a hard, wearable, corrode-resisting layer on the surface to enhance the mechanical property of the machine component. From 1980s, there is a new method of surface hardening that is heating with plasma arc. It overcomes the shortage of old methods and is adopted in automotive product ...

  6. Investigation of Hardened Filling Grout Samples

    Sørensen, Eigil V.

     Suzlon Wind Energy A/S requested on August 28, 2007 an investigation of 2 samples of a hardened filling grout to be carried out, comprising drilling and strength determination of 4 test cylinders, and description of the surface characteristics of the samples....... Suzlon Wind Energy A/S requested on August 28, 2007 an investigation of 2 samples of a hardened filling grout to be carried out, comprising drilling and strength determination of 4 test cylinders, and description of the surface characteristics of the samples....

  7. Induction surface hardening of hard coated steels

    Pantleon, Karen; Kessler, Olaf; Hoffmann, Franz


    . The effect of induction surface hardening on the properties of the coating-substrate-systems is mainly characterized using investigations of microstructure and chemical composition as well as measurements of hardness and residual stresses in dependence on the distance from the surface. Furthermore......, the scratch test is used to estimate critical loads for cohesive and adhesive failure of the coatings. Additionally, distortion measurements are carried out. The results emphasize the advantage of induction surface hardening as a method of subsequent heat treatment of CVD-coated steels....

  8. Biocorrosion study of titanium-cobalt alloys.

    Chern Lin, J H; Lo, S J; Ju, C P


    The present work provides experimental results of corrosion behaviour in Hank's physiological solution and some other properties of in-house fabricated titanium-cobalt alloys with cobalt ranging from 25-30% in weight. X-ray diffraction (XRD) shows that, in water-quenched (WQ) alloys, beta-titanium is largely retained, whereas in furnace-cooled (FC) alloys, little beta-titanium is found. Hardness of the alloys increases with increasing cobalt content, ranging from 455 VHN for WQ Ti-25 wt% Co to 525 VHN for WQ Ti-30 wt% Co. Differential thermal analysis (DTA) indicates that melting temperatures of the alloys are lower than that of pure titanium by about 600 degrees C. Potentiodynamic polarization results show that all measured break-down potentials in Hank's solution at 37 degrees C are higher than 800 mV. The breakdown potential for the FC Ti-25 Wt% Co alloy is even as high as nearly 1200 mV.

  9. Hardening by ion implantation of VT1-0 alloy having different grain size

    Nikonenko, Alisa, E-mail:; Kurzina, Irina, E-mail: [National Research Tomsk State University, 36, Lenin Str., 634050, Tomsk (Russian Federation); Popova, Natalya, E-mail: [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk Russia (Russian Federation); Nikonenko, Elena, E-mail: [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); National Research Tomsk Polytechnic University, 30, Lenin Str., 634050, Tomsk (Russian Federation); Kalashnikov, Mark, E-mail: [Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk Russia (Russian Federation)


    The paper presents a transmission electron microscopy (TEM) study of the structural and phase state of commercially pure titanium implanted by aluminum ions. TEM study has been carried out for two types of grains, namely coarse (0.4 µm) and small (0.5 µm). This paper presents details of the yield stress calculations and the analysis of strength components for the both grain types in two areas of the modified layer: at a distance of 0-150 nm (surface area I) and ∼300 nm (central area II) from the irradiated surface. It is shown that the ion implantation results in a considerable hardening of the entire thickness of the implanted layer in the both grain types. The grain size has, however, a different effect on the yield stress in areas I and II. Thus, near the ion-alloyed layer, the yield stress decreases with the increase of the grain size, whilst area II demonstrates its increase. Moreover, the contribution to the general hardening of the alloy made by certain hardening mechanisms differs from contributions made by each of these mechanisms in each certain case.

  10. HTPro: Low-temperature Surface Hardening of Stainless Steel

    Christiansen, Thomas Lundin; Somers, Marcel A. J.


    Low-temperature surface hardening of stainless steel provides the required performance properties without affecting corrosion resistance.......Low-temperature surface hardening of stainless steel provides the required performance properties without affecting corrosion resistance....

  11. Self hardening property of Botswana fly ash | Sahu | Botswana ...

    Self hardening property of Botswana fly ash. ... In the present investigation, an effort has been made to study the self hardening property of Botswana fly ash by ... This will encourage the use of fly ash economically as a construction material.

  12. Feasibility Studies on Underwater Laser Surface Hardening Process

    Biao Jin


    Full Text Available Laser surface hardening process is a very promising hardening method for ferrous and nonferrous alloys where transformations occur during cooling after laser melting in the solid state. This study experimentally characterizes laser surface hardening of tool steel in both water and air. For the underwater operation, laser surface scanning is performed over the tool steel surface which is immersed in water. The laser surface hardening tests are performed with a maximum 200 W fiber laser with a Gaussian distribution of energy in the beam. For the surface hardening, single-track melting experiment which sequentially scans elongated path of single line has been performed. As the hardened depth depends on the thermal conductivity of the material, the surface temperature and the penetration depth may be varied by underwater laser processing. The feasibility of underwater laser surface hardening process is discussed on the basis of average hardness level and hardened bead shape.

  13. Feasibility Studies on Underwater Laser Surface Hardening Process

    Biao Jin; Min Li; TaeWoo Hwang; YoungHoon Moon


    Laser surface hardening process is a very promising hardening method for ferrous and nonferrous alloys where transformations occur during cooling after laser melting in the solid state. This study experimentally characterizes laser surface hardening of tool steel in both water and air. For the underwater operation, laser surface scanning is performed over the tool steel surface which is immersed in water. The laser surface hardening tests are performed with a maximum 200 W fiber laser with a ...



    The invention relates to case-hardening of a stainless steel article by means of gas including carbon and/or nitrogen, whereby carbon and/or nitrogen atoms diffuse through the surface into the article. The method includes activating the surface of the article, applying a top layer on the activated...

  15. Instabilities in power law gradient hardening materials

    Niordson, Christian Frithiof; Tvergaard, Viggo


    Tension and compression instabilities are investigated for specimens with dimensions in the micron range. A finite strain generalization of a higher order strain gradient plasticity theory is implemented in a finite element scheme capable of modeling power law hardening materials. Effects...

  16. Beta Thalassemia

    Beta thalassemia is found in people of Mediterranean, Middle Eastern, African, South Asian (Indian, Pakistani, etc.), Southeast Asian and Chinese descent. 1 Beta Thalassemia ßß Normal beta globin genes found on chromosomes ...

  17. A New Method of Hardening Inner Wall of Long Pipe


    A new laser inner wall hardening method for long pipe mas introduced. The system combines laser surface hardening with robot moving in pipeline. Some craft experiments have been done with this system and optimum parameters of laser hardening have been found.

  18. Improvement of the fatigue life of titanium alloys for biomedical devices through microstructural control.

    Niinomi, Mitsuo; Akahori, Toshikazu


    A limited number of reports exist regarding the systematic investigation or comparison of the fatigue strength of titanium alloys for medical devices, including plain, fretting and notch fatigue, for improvement through various treatments and processes, with respect to related microstructures. This article focuses on the changes and improvements in fatigue strength of newly developed beta-type and practically used alpha + beta-titanium alloys for medical devices through heat treatments, thermomechanical treatments and surface modifications.

  19. Effect of whitening toothpaste on titanium and titanium alloy surfaces

    Faria, Adriana Cláudia Lapria; Bordin, Angelo Rafael de Vito; Pedrazzi, Vinícius; Rodrigues, Renata Cristina Silveira; Ribeiro, Ricardo Faria


    .... Whitening toothpastes with peroxides are available for patients with high aesthetic requirements, but the effect of whitening toothpastes on titanium surfaces is not yet known, although titanium...

  20. A minimum 2-year comparative study of autologous cancellous bone grafting versus beta-tricalcium phosphate in anterior cervical discectomy and fusion using a rectangular titanium stand-alone cage.

    Yamagata, Toru; Naito, Kentaro; Arima, Hironori; Yoshimura, Masaki; Ohata, Kenji; Takami, Toshihiro


    Although titanium stand-alone cages are commonly used in anterior cervical discectomy and fusion (ACDF), there are several concerns such as cage subsidence after surgery. The efficacy of β-tricalcium phosphate (β-TCP) granules as a packing material in 1- or 2-level ACDF using a rectangular titanium stand-alone cage is not fully understood. The purpose of this study is to investigate the validity of rectangular titanium stand-alone cages in 1- and 2-level ACDF with β-TCP. This retrospective study included 55 consecutive patients who underwent ACDF with autologous iliac cancellous bone grafting and 45 consecutive patients with β-TCP grafting. All patients completed at least 2-year postoperative follow-up. Univariate and multivariate analyses were performed to examine the associations between study variables and nonunion after surgery. Significant neurological recovery after surgery was obtained in both groups. Cage subsidence was noted in 14 of 72 cages (19.4 %) in the autograft group and 12 of 64 cages (18.8 %) in the β-TCP group. A total of 66 cages (91.7 %) in the autograft group showed osseous or partial union, and 58 cages (90.6 %) in the β-TCP group showed osseous or partial union by 2 years after surgery. There were no significant differences in cage subsidence and the bony fusion rate between the two groups. Multivariate analysis using a logistic regression model showed that fusion level at C6/7, 2-level fusion, and cage subsidence of grades 2-3 were significantly associated with nonunion at 2 years after surgery. Although an acceptable surgical outcome with negligible complication appears to justify the use of rectangular titanium stand-alone cages in 1- and 2-level ACDF with β-TCP, cage subsidence after surgery needs to be avoided to achieve acceptable bony fusion at the fused segments. Fusion level at C6/7 or 2-level fusion may be another risk factor of nonunion.

  1. Production of new titanium alloy for orthopedic implants

    Taddei, E.B. [Instituto Tecnologico de Aeronautica (ITA), Centro Tecnico Aeroespacial, Sao Jose dos Campos-SP, 12228-904 (Brazil)]. E-mail:; Henriques, V.A.R. [AMR-DiviSao de Materiais-Instituto de Aeronautica e Espaco (IAE), Centro Tecnico Aeroespacial, Sao Jose dos Campos-SP, 12228-904 (Brazil); Silva, C.R.M. [AMR-DiviSao de Materiais-Instituto de Aeronautica e Espaco (IAE), Centro Tecnico Aeroespacial, Sao Jose dos Campos-SP, 12228-904 (Brazil); Cairo, C.A.A. [AMR-DiviSao de Materiais-Instituto de Aeronautica e Espaco (IAE), Centro Tecnico Aeroespacial, Sao Jose dos Campos-SP, 12228-904 (Brazil)


    The beta titanium alloys is one of the most promising groups of the titanium alloys. This fact is due to the good formability, mechanical properties and potential applications; moreover, these alloys present the highest level of mechanical, fatigue and corrosion resistance. The beta titanium alloys present the lowest elastic modulus, an interesting property for orthopedic implants. A {beta} alloy recently developed for this application is Ti-35Nb-7Zr-5Ta. In this work, the alloy was produced by powder metallurgy, unique available alternative for obtaining parts with porous structure (until 50% of porosity), that is one important characteristic for the osteointegration. The Ti-35Nb-7Zr-5Ta samples were manufactured by blended elemental method from a sequence of uniaxial and cold isostatic pressing with subsequent densification by sintering among 900 at 1700 deg. C, in vacuum. The objective of this work is the analysis of alloy microstructural evolution from the elemental powders dissolution under the increase of the sintering temperature. The alloy was characterized by scanning electron microscopy, X-ray diffraction and Vickers microhardness measurements. Density was measured by Archimedes method. The results show that a {beta}-homogeneous microstructure is obtained in the whole sample with the increase of sintering temperature. With the beginning of the {beta}-stabilizers (Nb and Ta) dissolution, at low sintering temperatures, there is the formation of an intermediary Widmanstaetten ({alpha}+{beta}) phase.

  2. Origin of the Cosmic Ray Spectral Hardening

    Tomassetti, N


    Recent data from ATIC, CREAM and PAMELA indicate that the cosmic ray energy spectra of protons and nuclei exhibit a remarkable hardening at energies above 100 GeV per nucleon. We propose that the hardening is an interstellar propagation effect that originates from a spatial change of the cosmic ray transport properties in different regions of the Galaxy. The key hypothesis is that the diffusion coefficient is not separable into energy and space variables as usually assumed. Under this scenario, we can reproduce well the observational data. Our model has several implications for the cosmic ray acceleration/propagation physics and can be tested by ongoing experiments such as AMS or Fermi/LAT.

  3. Construction procedures using self hardening fly ash

    Thornton, S. I.; Parker, D. G.


    Fly ash produced in Arkansas from burning Wyoming low sulfur coal is self-hardening and can be effective as a soil stabilizing agent for clays and sands. The strength of soil-self hardening fly ash develops rapidly when compacted immediately after mixing. Seven day unconfined compressive strengths up to 1800 psi were obtained from 20% fly ash and 80% sand mixtures. A time delay between mixing the fly ash with the soil and compaction of the mixture reduced the strength. With two hours delay, over a third of the strength was lost and with four hours delay, the loss was over half. Gypsum and some commercial concrete retarders were effective in reducing the detrimental effect of delayed compaction. Adequate mixing of the soil and fly ash and rapid compaction of the mixtures were found to be important parameters in field construction of stabilized bases.

  4. Radiation-hardened transistor and integrated circuit

    Ma, Kwok K.


    A composite transistor is disclosed for use in radiation hardening a CMOS IC formed on an SOI or bulk semiconductor substrate. The composite transistor has a circuit transistor and a blocking transistor connected in series with a common gate connection. A body terminal of the blocking transistor is connected only to a source terminal thereof, and to no other connection point. The blocking transistor acts to prevent a single-event transient (SET) occurring in the circuit transistor from being coupled outside the composite transistor. Similarly, when a SET occurs in the blocking transistor, the circuit transistor prevents the SET from being coupled outside the composite transistor. N-type and P-type composite transistors can be used for each and every transistor in the CMOS IC to radiation harden the IC, and can be used to form inverters and transmission gates which are the building blocks of CMOS ICs.


    O. V. Dvornikov


    Full Text Available Problems of specialized analog integrated circuit design for sensor equipments are considered. It is offered to produce of radiation hardened analog IC on structured chips for economic efficiency at small production volume. The approach to analog IC design is described, including recommendations for choice of: types and quantities of structured chip analogue components; active and passive components; schematic decisions of analogue components with programmed parameters and small sensitivity to radiation. 

  6. Dislocation Multi-junctions and Strain Hardening

    Bulatov, V; Hsiung, L; Tang, M; Arsenlis, A; Bartelt, M; Cai, W; Florando, J; Hiratani, M; Rhee, M; Hommes, G; Pierce, T; Diaz de la Rubia, T


    At the microscopic scale, the strength of a crystal derives from the motion, multiplication and interaction of distinctive line defects--dislocations. First theorized in 1934 to explain low magnitudes of crystal strength observed experimentally, the existence of dislocations was confirmed only two decades later. Much of the research in dislocation physics has since focused on dislocation interactions and their role in strain hardening: a common phenomenon in which continued deformation increases a crystal's strength. The existing theory relates strain hardening to pair-wise dislocation reactions in which two intersecting dislocations form junctions tying dislocations together. Here we report that interactions among three dislocations result in the formation of unusual elements of dislocation network topology, termed hereafter multi-junctions. The existence of multi-junctions is first predicted by Dislocation Dynamics (DD) and atomistic simulations and then confirmed by the transmission electron microscopy (TEM) experiments in single crystal molybdenum. In large-scale Dislocation Dynamics simulations, multi-junctions present very strong, nearly indestructible, obstacles to dislocation motion and furnish new sources for dislocation multiplication thereby playing an essential role in the evolution of dislocation microstructure and strength of deforming crystals. Simulation analyses conclude that multi-junctions are responsible for the strong orientation dependence of strain hardening in BCC crystals.

  7. Beam hardening correction algorithm in microtomography images

    Sales, Erika S.; Lima, Inaya C.B.; Lopes, Ricardo T., E-mail: esales@con.ufrj.b, E-mail: ricardo@lin.ufrj.b [Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Instrumentacao Nuclear; Assis, Joaquim T. de, E-mail: joaquim@iprj.uerj.b [Universidade do Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil). Inst. Politecnico. Dept. de Engenharia Mecanica


    Quantification of mineral density of bone samples is directly related to the attenuation coefficient of bone. The X-rays used in microtomography images are polychromatic and have a moderately broad spectrum of energy, which makes the low-energy X-rays passing through a sample to be absorbed, causing a decrease in the attenuation coefficient and possibly artifacts. This decrease in the attenuation coefficient is due to a process called beam hardening. In this work the beam hardening of microtomography images of vertebrae of Wistar rats subjected to a study of hyperthyroidism was corrected by the method of linearization of the projections. It was discretized using a spectrum in energy, also called the spectrum of Herman. The results without correction for beam hardening showed significant differences in bone volume, which could lead to a possible diagnosis of osteoporosis. But the data with correction showed a decrease in bone volume, but this decrease was not significant in a confidence interval of 95%. (author)

  8. Plasma Nitriding of CP Titanium Grade-2 and Ti-6Al-4V Grade-5

    Deepak, J. R.; Bupesh Raja, V. K.; Senthil Kumar, J.; Thomas, Subin; Raju Vithaiyathil, Thomas


    Titanium metal is considered to be asset material due to its high tribological properties. Since these tribological properties like hardness, roughness, wear resistance etc. are influenced by the surface properties of the material, so obviously any changes in the surface of the material has direct impact on the tribological properties too. Nitriding is a heat-treating process that diffuses nitrogen into the surface of a metal to create a case hardened surface. The main objective is that to implement the plasma nitriding process to both CP Titanium grade-2 and Ti-6Al-4V grade-5 and to observe the improvements in the tribological properties with respect to the parent materials.

  9. Empirical beam hardening correction (EBHC) for CT

    Kyriakou, Yiannis; Meyer, Esther; Prell, Daniel; Kachelriess, Marc [Institute of Medical Physics, University of Erlangen-Nuernberg, 91052 Erlangen (Germany)


    Purpose: Due to x-ray beam polychromaticity and scattered radiation, attenuation measurements tend to be underestimated. Cupping and beam hardening artifacts become apparent in the reconstructed CT images. If only one material such as water, for example, is present, these artifacts can be reduced by precorrecting the rawdata. Higher order beam hardening artifacts, as they result when a mixture of materials such as water and bone, or water and bone and iodine is present, require an iterative beam hardening correction where the image is segmented into different materials and those are forward projected to obtain new rawdata. Typically, the forward projection must correctly model the beam polychromaticity and account for all physical effects, including the energy dependence of the assumed materials in the patient, the detector response, and others. We propose a new algorithm that does not require any knowledge about spectra or attenuation coefficients and that does not need to be calibrated. The proposed method corrects beam hardening in single energy CT data. Methods: The only a priori knowledge entering EBHC is the segmentation of the object into different materials. Materials other than water are segmented from the original image, e.g., by using simple thresholding. Then, a (monochromatic) forward projection of these other materials is performed. The measured rawdata and the forward projected material-specific rawdata are monomially combined (e.g., multiplied or squared) and reconstructed to yield a set of correction volumes. These are then linearly combined and added to the original volume. The combination weights are determined to maximize the flatness of the new and corrected volume. EBHC is evaluated using data acquired with a modern cone-beam dual-source spiral CT scanner (Somatom Definition Flash, Siemens Healthcare, Forchheim, Germany), with a modern dual-source micro-CT scanner (TomoScope Synergy Twin, CT Imaging GmbH, Erlangen, Germany), and with a modern

  10. Influence of structure on nickel-titanium endodontic instruments failure.

    Kuhn, G; Tavernier, B; Jordan, L


    The purpose of this work was to investigate the process history on fracture life of nickel-titanium endodontics files. The results are based on microstructural investigations of nickel-titanium engine-driven rotary instruments based on X-ray diffraction, scanning electron microscopy, and microhardness tests. Endodontic files are very work-hardened, and there is a high density of defects in the alloy that can disturb the phase transformation. The microhardness Vickers confirmed these observations (dislocations and precipitates). The X-rays show that experimental spectrum lines are extended, typical of a distorted lattice. The surface state of the endodontic files (scanning electron microscopy) is an important factor in failure and fracture initiation.

  11. Isothermal Aging Precipitate of TB17 Titanium Alloy

    WANG Zhe


    Full Text Available Transmission Electron Microscope (TEM, X-Ray Diffraction(XRD and Optical Microscope(OMwere employed to investigate the aging precipitation behavior of a new type of ultra-high strength TB17 titanium alloy. The results show that during heat solution treated in the β phase field followed by aging the secondary α phase is nucleated, precipitated and grew on the β phase matrix,and the precipitated phase is lamellar structure which has burgers relation with the matrix. The secondary α phase content is increased rapidly and finally reach a steady-state as aging time increased and the final product of aging consists of α phase and β phase. there is a good linearity relationship between the content of secondary α phase and the hardness of age hardening. The TB17 titanium alloy isothermal phase transformation kinetics can be described by JMAK equation.

  12. Recent advances in the design of titanium alloys for orthopedic applications.

    Guillemot, Fabien


    To increase an orthopedic implant's lifetime, research trends have included the development of new titanium alloys made of nontoxic elements with suitable mechanical properties (low Young's modulus - high fatigue strength), good workability and corrosion resistance. In accordance with the background on titanium and metallic biomaterials, recent interesting developments in titanium-based biomaterials are reported in this review, with a special emphasis on the design of new metastable beta-titanium alloys for orthopedic applications. In addition, as the concept of titanium alloys can now be regarded as relatively old, having emerged at the beginning of the 1980s, the author suggests some future directions that would permit the emergence of a new generation of titanium implants.

  13. Effect of Overaging on Solute Distributions and Bake Hardening Phenomenon in Bake Hardening Steels%Effect of Overaging on Solute Distributions and Bake Hardening Phenomenon in Bake Hardening Steels

    WANG Hua; SHI Wen; HE Yan-lin; LU Xiao-gang; LI Lin


    Specimens of two different kinds of bake hardening steels (BH-Mn and BH-P) were prepared and treated with different annealing processes (water quenching and overaging). A novel technique of three dimensional atom probe was used to investigate solute distributions in these steels. The results indicate that C concentration decreases, whereas V increases during overaging in both bake hardening steels. The conclusion that no vanadium carbides pre- cipitate during the overaging is therefore originally obtained by microanalysis in bake hardening steels. Moreover, bake hardening values of all the specimens were tested by tensile experiments with 2 0/~ pre-deformation. However, those of overaged specimens were further measured with higher levels of pre-deformation because no bake hardening phenomenon was present at 2% pre-deformation. As the pre-deformation increases from 2% to 6% and 8%, both overaged steels show bake hardening values, and the value data are almost the same.

  14. Effect of cysteine on lowering protein aggregation and subsequent hardening of whey protein isolate (WPI) protein bars in WPI/buffer model systems.

    Zhu, Dan; Labuza, Theodore P


    Whey protein isolate (WPI) bar hardening without and with cysteine (Cys) or N-ethylmaleimide (NEM) was investigated in model systems (WPI/buffer = 6:4, by weight, pH 6.8, a(w) approximately 0.97) in an accelerated shelf-life test (ASLT) at 45 degrees C over a period of up to 35 days. The formation of insoluble aggregates as determined by solubility and the structural rearrangement of WPI protein aggregates as observed by SEM were responsible for the WPI bars' hardening. As corroborated by electrophoresis analysis, both beta-lactoglobulin (beta-lg) and alpha-lactalbumin (alpha-la) were involved in the formation of aggregates via the thiol-disulfide interchange reaction and/or noncovalent interactions. The former force dominated the bar hardening at an earlier stage, whereas the latter force played a role for the long-term hardening. In comparison with the control bar without Cys, the thiol-disulfide interchange reaction was significantly reduced by Cys (WPI/Cys = 0.05), increased by Cys (WPI/Cys = 0.25), and inhibited by NEM (WPI/NEM = 2). Therefore, bar hardening was significantly delayed by Cys (WPI/Cys = 0.05) and NEM but accelerated by Cys (WPI/Cys = 0.25).

  15. The effect of microstructure on the fracture toughness of titanium alloys

    Vanstone, R. H.; Low, J. R., Jr.; Shannon, J. L., Jr.


    The microstructure of the alpha titanium alloy Ti-5Al-2.5Sn and the metastable beta titanium alloy Beta 3 was examined. The material was from normal and extra low interstitial grade plates which were either air-cooled or furnace-cooled from an annealing treatment. Beta 3 was studied in alpha-aged and omega-aged plates which were heat treated to similar strength levels. Tensile and plane strain fracture toughness tests were conducted at room temperature on the alpha-aged material. The microstructure and fracture mechanisms of alloys were studied using optical metallography, electron microscopy, microprobe analyses, and texture pole figures. Future experiments are described.

  16. Laser Surface Hardening of 9CrSi Steel


    The effects of laser hardening parameters such as beam power, beam diameter and scanning rate on microstructureand hardness of 9CrSi steel were investigated. The microstructure of the surface layer of 9CrSi steel was changed frompearlite to martensite, retained austenite and carbide by laser hardening. The depth of the hardened layer increasedwith increasing laser energy density and the surface hardeness increased by 3~5 times as high as the untreated steel.The laser hardened surface had good wear resistance due to martensite and carbide in the surface layer. The wearmode at Iow speed was abrasive, while the wear mode at high speed was adhesive.

  17. Configurable Radiation Hardened High Speed Isolated Interface ASIC Project

    National Aeronautics and Space Administration — NVE Corporation will design and build an innovative, low cost, flexible, configurable, radiation hardened, galvanically isolated, interface ASIC chip set that will...




    Full Text Available This paper deals with the study of the performance of coated tools in machining hardening steel under dry conditions. This paper involves of machining AISI 4340 hardened steel using coated carbide tools is studied using full factorial experiments. Many parameters influence the quality of the products in hard turning process. The objective of this study is on the effect of the cutting conditions such as cutting velocity, feed, and depth of cut on the surface finish in machining AISI 4340 hardened steel. Machining of hardened steels has become an important manufacturing process, particularly in the automotive and bearing industries.

  19. Additive strengthening mechanisms in dispersion hardened polycrystals

    Hansen, Niels; Ralph, B.


    Tensile data from polycrystalline samples of copper dispersion strengthened by alumina are analysed. The basis of this analysis is to look at the strain range from 0.05 to 0.20 where the stress-strain curves show a parabolic hardening behaviour and are parallel to one another. The means by which...... the dislocation density contributions from each of these three sources. The type of additivity suggested here not only gives very good agreement with the stress-strain data but it also uses and is in accord with the experimental measurements of dislocation densities made using transmission electron microscopy....

  20. Degradation of titanium drillpipe from corrosion and wear

    Ferg, T.E.; Aldrich, C.S. (Colorado School of Mines, Golden, CO (United States)); Craig, B.D. (Metallurgical Consultants Inc., Montebello (United States))


    Drilling deeper than 35,000 ft is limited by the extreme hook loads of steel drillpipe and temperature constraints of aluminum drillpipe. Titanium Alloys Ti-6Al-4V and Beta C have been proposed for use in drillpipe for wells deeper than 35,000 ft because of their high strength/weight ratios, superior high-temperature corrosion resistance, and thermal stability. Their suitability in drilling environments, however, has not been evaluated. To determine the corrosion and wear characteristics of two types of titanium-alloy drillpipe under dogleg conditions, a test cell was constructed to test titanium drillpipe joints in contact with API Spec. 5CT Grade P-110 casing in different drilling muds. Titanium-alloy pipe and Grade P-110 casing wear rates were measured, and tests showed that both titanium-alloy pipes exhibited much greater wear than did steel drillpipe in water-based mud under the same conditions. Test data showed that the total wear rate of Alloys Ti-6Al-4V and Beta C in a drilling environment is a combination of mechanical wear and corrosion.

  1. Mechanism of unique hardening of dental Ag-Pd-Au-Cu alloys in relation with constitutional phases

    Kim, Yonghwan [Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6 Aoba, Aramaki Aza, Aoba-ku, Sendai 980-8579 (Japan); Niinomi, Mitsuo, E-mail: [Department of Biomaterials Science, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Nakai, Masaaki; Akahori, Toshikazu [Department of Biomaterials Science, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Kanno, Toru [Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6 Aoba, Aramaki Aza, Aoba-ku, Sendai 980-8579 (Japan); Fukui, Hisao [Department of Dental Materials Science, School of Dentistry, Aichi-Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650 (Japan)


    Highlights: Black-Right-Pointing-Pointer The unique hardening behavior on Ag-Pd-Au-Cu alloys by solution treatment was investigated. Black-Right-Pointing-Pointer The Cu-rich {alpha}{sub 1} phase and Ag-rich {alpha}{sub 2} phase decomposed by solution treatment contributed weakly to the change of hardness. Black-Right-Pointing-Pointer The fine {beta} phases precipitated by aging treatment caused great increase in hardness. Black-Right-Pointing-Pointer The fine L1{sub 0}-type ordered {beta} Prime phase precipitated by solution treatment may contribute to the unique hardening behavior. - Abstract: The objective of this research was to investigate the effect of constitutional phases on the unique hardening behavior of as-solutionized dental Ag-Pd-Au-Cu alloy fabricated by cold rolling. The commercial dental Ag-Pd-Au-Cu alloy fabricated by cold rolling consists of Cu-rich {alpha}{sub 1}, Ag-rich {alpha}{sub 2}, and {beta} phases. On the other hand, the Ag-Pd-Au-Cu alloy fabricated by the liquid rapid solidification (LRS) method consists of single {alpha} phase. They were subjected to various heat treatments, respectively. The microstructures were observed by scanning electron microscope, transmission electron microscope and X-ray diffraction. The hardness was evaluated by a Vickers micro-hardness tester. In the Ag-Pd-Au-Cu alloy fabricated by cold rolling, the fine L1{sub 0}-type-ordered {beta} Prime phase is precipitated and the coarse {beta} phase is remained after solution treatment at 1123 K. The hardness increases drastically. On the other hand, in the Ag-Pd-Au-Cu alloy fabricated by LRS method, the single {alpha} phase was decomposed into the {alpha}{sub 1} phase and the {alpha}{sub 2} phase after solution treatment at 1023 K and its hardness change was small. However, after aging treatment at 673 K, the fine {beta} phase is precipitated in the {alpha} phase and the hardness increases greatly even in the Ag-Pd-Au-Cu alloy fabricated by LRS method. It is considered

  2. Hardened Client Platforms for Secure Internet Banking

    Ronchi, C.; Zakhidov, S.

    We review the security of e-banking platforms with particular attention to the exploitable attack vectors of three main attack categories: Man-in-the-Middle, Man-in-the-PC and Man-in-the-Browser. It will be shown that the most serious threats come from combination attacks capable of hacking any transaction without the need to control the authentication process. Using this approach, the security of any authentication system can be bypassed, including those using SecureID Tokens, OTP Tokens, Biometric Sensors and Smart Cards. We will describe and compare two recently proposed e-banking platforms, the ZTIC and the USPD, both of which are based on the use of dedicated client devices, but with diverging approaches with respect to the need of hardening the Web client application. It will be shown that the use of a Hardened Browser (or H-Browser) component is critical to force attackers to employ complex and expensive techniques and to reduce the strength and variety of social engineering attacks down to physiological fraud levels.

  3. Hardness variability in commercial and hardened technologies

    Shaneyfelt, M.R.; Winokur, P.S.; Meisenheimer, T.L.; Sexton, F.W.; Roeske, S.B.; Knoll, M.G.


    Over the past 10 years, there have been a number of advances in methods to assess and assure the radiation hardness of microelectronics in military and space applications. At the forefront of these is the Qualified Manufacturers List (QML) methodology, in which the hardness of product is ``built-in`` through statistical process control (SPC) of technology parameters relevant to the radiation response, test structure to integrated circuit (IC) correlations, and techniques for extrapolating laboratory test results to varying radiation scenarios. At the same time, there has been renewed interest in the use of commercial technology -- with its enhanced performance, reduced cost, and higher reliability -- in military and space systems. In this paper, we initially demonstrate the application of QML techniques to assure and control the radiation response of hardened technologies. Through several examples, we demonstrate intra-die, wafer-to-wafer, and lot-to-lot variations in a hardened technology. We observe 10 to 30% variations in key technology parameters that result from variability in geometry, process, and design layout. Radiation-induced degradation is seen to mirror preirradiation characteristics. We then evaluate commercial technologies and report considerably higher variability in radiation hardness, i.e., variations by a factor of two to five. This variability is shown to arise from a lack of control of technology parameters relevant to the radiation response, which a commercial manufacturer has no interest in controlling in a normal process flow.

  4. Machining of titanium alloys


    This book presents a collection of examples illustrating the resent research advances in the machining of titanium alloys. These materials have excellent strength and fracture toughness as well as low density and good corrosion resistance; however, machinability is still poor due to their low thermal conductivity and high chemical reactivity with cutting tool materials. This book presents solutions to enhance machinability in titanium-based alloys and serves as a useful reference to professionals and researchers in aerospace, automotive and biomedical fields.

  5. Titanium allergy: A literature review

    Manish Goutam


    Full Text Available Titanium has gained immense popularity and has successfully established itself as the material of choice for dental implants. In both medical and dental fields, titanium and its alloys have demonstrated success as biomedical devices. Owing to its high resistance to corrosion in a physiological environment and the excellent biocompatibility that gives it a passive, stable oxide film, titanium is considered the material of choice for intraosseous use. There are certain studies which show titanium as an allergen but the resources to diagnose titanium sensivity are very limited. Attention is needed towards the development of new and precise method for early diagnosis of titanium allergy and also to find out the alternative biomaterial which can be used in place of titanium. A review of available articles from the Medline and PubMed database was done to find literature available regarding titanium allergy, its diagnosis and new alternative material for titanium.

  6. Strain rate dependence of the flow stress and work hardening of {gamma}`

    Ezz, S.S. [Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH (United Kingdom); Sun, Y.Q. [Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH (United Kingdom); Hirsch, P.B. [Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH (United Kingdom)


    The strain rate ({epsilon}) sensitivity of the flow stress ({tau}), {beta}=({delta}{tau}/{delta} ln{epsilon}), of crystals of {gamma}` in the temperature (T) range of the yield stress anomaly obeys a Cottrell-Stokes law when plotted against {tau}{sub h}={tau}-{tau}{sub y}, where {tau}{sub y} is the yield stress at 0.01% strain. The slopes are approximately 1%, decrease with increasing T and are approximately independent of orientation. {tau}{sub h} is due to work hardening and depends on the prestrain {epsilon}, {epsilon} and T. Transmission electron microscopy observations suggest that at 2% strain at 600 K and 720 K, {tau}{sub h} and {beta} are mainly controlled by forest obstacles. At 600 K, the forest consists largely of [101] dislocations on the (010) cross slip plane threading the (111) planes and generated by bowing of the [101] primary screws (Kear-Wilsdorf locks). At 720 K, the forest is non-uniform and consists of [101] on (010), primary cube [110] on (001) and secondary octahedral slip dislocations. At room temperature, the strength of the obstacles is weaker and it is suggested that they are mainly jogs on edge dislocations generated by cross slip of screw segments. At 2% strain, fine slip on (010) and (001) contributes increasingly to strain with increasing T and this correlates with the decrease in the work-hardening rate. ((orig.))

  7. Mechanical biocompatibilities of titanium alloys for biomedical applications.

    Niinomi, Mitsuo


    Young's modulus as well as tensile strength, ductility, fatigue life, fretting fatigue life, wear properties, functionalities, etc., should be adjusted to levels that are suitable for structural biomaterials used in implants that replace hard tissue. These factors may be collectively referred to as mechanical biocompatibilities. In this paper, the following are described with regard to biomedical applications of titanium alloys: the Young's modulus, wear properties, notch fatigue strength, fatigue behaviour on relation to ageing treatment, improvement of fatigue strength, fatigue crack propagation resistance and ductility by the deformation-induced martensitic transformation of the unstable beta phase, and multifunctional deformation behaviours of titanium alloys.

  8. Titanium: the mystery metal of implant dentistry. Dental materials aspects.

    Parr, G R; Gardner, L K; Toth, R W


    A number of important points concerning titanium and its alloys have been discussed. They are summarized as follows. Ti and its alloys, particularly the alpha-beta alloys, possess mechanical properties that make them ideal implant materials. Ti and its alloys oxidize readily in air. This surface oxide is extremely stable in the physiologic environment of the body. The stability and inertness of this surface oxide layer acts to protect Ti from corrosive breakdown when used in the body. The elimination of surface irregularities and contaminants is important when preparing a metal for implantation. Titanium can be coupled with equally passive metals in the body without causing galvanic corrosion.

  9. Optimization of Laser Beam Transformation Hardening by One Single Parameter

    Meijer, J.; Sprang, van I.


    The process of laser beam transformation hardening is principally controlled by two independent parameters, the absorbed laser power on a given area and the interaction time. These parameters can be transformed into two functional parameters: the maximum surface temperature and the hardening depth.

  10. [Hardening of dental tissue by CO2 laser radiation].

    Aboites, V; Díaz, O; Cuevas, F


    A study was conducted to test the effects of CO2 laser irradiation on dental tissue. It was found that hardening of the dental tissue occurs. This was observed qualitatively by direct observation and by X-ray radiography. The hardening produced was also quantitatively measured using a hardness-meter on Rockwell scale.

  11. Design and characterization of cellulose nanocrystal-enhanced epoxy hardeners

    Shane X. Peng; Robert J. Moon; Jeffrey P. Youngblood


    Cellulose nanocrystals (CNCs) are renewable, sustainable, and abundant nanomaterial widely used as reinforcing fillers in the field of polymer nanocomposites. In this study, two-part epoxy systems with CNC-enhanced hardeners were fabricated. Three types of hardeners, Jeffamine D400 (JD400), diethylenetriamine (DETA), and (±)-trans-1,2- diaminocyclohexane (DACH), were...


    HESS, F


    A new viscoplastic model for the plastic stress-strain behaviour of f.c.c. metals is presented. In this model the strain hardening results from increasing dislocation densities. The observed stagnation of strain hardening after strain reversals is explained by a lowering of the increase in dislocati

  13. Modeling of state parameter and hardening function for granular materials

    彭芳乐; 李建中


    A modified plastic strain energy as hardening state parameter for dense sand was proposed, based on the results from a series of drained plane strain tests on saturated dense Japanese Toyoura sand with precise stress and strain measurements along many stress paths. In addition, a unique hardening function between the plastic strain energy and the instantaneous stress path was also presented, which was independent of stress history. The proposed state parameter and hardening function was directly verified by the simple numerical integration method. It is shown that the proposed hardening function is independent of stress history and stress path and is appropriate to be used as the hardening rule in constitutive modeling for dense sand, and it is also capable of simulating the effects on the deformation characteristics of stress history and stress path for dense sand.

  14. Precipitation hardening in 350 grade maraging steel

    Viswanathan, U.K. (Bhabha Atomic Research Centre, Bombay, (India). Radiometallurgy Div.); Dey, G.K. (Bhabha Atomic Research Centre, Bombay, (India). Metallurgy Division); Asundi, M.K. (Government Colony, Bombay, (India))


    Evolution of microstructure in 350 grade commercial maraging steel has been examined. In the earlier stages of aging, the strengthening phases are formed by the heterogeneous precipitation, and these phases have been identified as intermetallic compounds of the Ni[sub 3] (Ti, Mo) and Fe[sub 2]Mo types. The kinetics of precipitation are studied in terms of the activation energy by carrying out isothermal hardness measurements of aged material. The mechanical properties in the peak-aged and overaged conditions were evaluated and the flow behavior examined. The overaging behavior of the steel has been studied and the formation of austenite of different morphologies identified. The crystallography of the austenite has been examined in detail. From the microstructural examination of peak-aged and deformed samples, it could be inferred that the dislocation-precipitate interaction is by precipitate shearing. Increased work hardening of the material in the overaged condition was suggestive of looping of precipitates by dislocations.

  15. Precipitation hardening in 350 grade maraging steel

    Viswanathan, U. K.; Dey, G. K.; Asundi, M. K.


    Evolution of microstructure in a 350 grade commercial maraging steel has been examined. In the earlier stages of aging, the strengthening phases are formed by the heterogeneous precipitation, and these phases have been identified as intermetallic compounds of the Ni3 (Ti, Mo) and Fe2Mo types. The kinetics of precipitation are studied in terms of the activation energy by carrying out isothermal hardness measurements of aged material. The mechanical properties in the peak-aged and overaged conditions were evaluated and the flow behavior examined. The overaging behavior of the steel has been studied and the formation of austenite of different morphologies identified. The crystallography of the austenite has been examined in detail. From the microstructural examination of peak-aged and deformed samples, it could be inferred that the dislocation-precipitate interaction is by precipitate shearing. Increased work hardening of the material in the overaged condition was suggestive of looping of precipitates by dislocations.

  16. Jerky loads on surface-hardened gears

    Rettig, H.; Wirth, X.


    Damage occurs again and again in practice in the form of transmissions with surface hardened gears which break after a very long operating time (explained by seldom occurring jerky loads). Gear drives are frequently exposed to jerky stresses which are greater than their fatigue limit. These stresses are considered in gear calculations, first, by shock factors when the transmission is to be designed as high endurance with regard to overloads and, second, in the form of operating ratios when the design is to be time enduring with regard to overloads. The size of the operating ratio depends not only on torque characteristics, drive and processing machine, but also on the material and heat treatment.

  17. Keystroke Dynamics-Based Credential Hardening Systems

    Bartlow, Nick; Cukic, Bojan

    abstract Keystroke dynamics are becoming a well-known method for strengthening username- and password-based credential sets. The familiarity and ease of use of these traditional authentication schemes combined with the increased trustworthiness associated with biometrics makes them prime candidates for application in many web-based scenarios. Our keystroke dynamics system uses Breiman’s random forests algorithm to classify keystroke input sequences as genuine or imposter. The system is capable of operating at various points on a traditional ROC curve depending on application-specific security needs. As a username/password authentication scheme, our approach decreases the system penetration rate associated with compromised passwords up to 99.15%. Beyond presenting results demonstrating the credential hardening effect of our scheme, we look into the notion that a user’s familiarity to components of a credential set can non-trivially impact error rates.

  18. Dilatant hardening of fluid-saturated sandstone

    Makhnenko, Roman Y.; Labuz, Joseph F.


    The presence of pore fluid in rock affects both the elastic and inelastic deformation processes, yet laboratory testing is typically performed on dry material even though in situ the rock is often saturated. Techniques were developed for testing fluid-saturated porous rock under the limiting conditions of drained, undrained, and unjacketed response. Confined compression experiments, both conventional triaxial and plane strain, were performed on water-saturated Berea sandstone to investigate poroelastic and inelastic behavior. Measured drained response was used to calibrate an elasto-plastic constitutive model that predicts undrained inelastic deformation. The experimental data show good agreement with the model: dilatant hardening in undrained triaxial and plane strain compression tests under constant mean stress was predicted and observed.

  19. Spectral Hardening and Geoeffectiveness of Solar Flares

    Jain, R.; Kumar, S.; Dave, H.; Deshpande, M. R.

    We present the results of a few typical flares that observed by the first space borne solar astronomy experiment of India namely "Solar X-ray Spectrometer (SOXS)" mission, which has completed one year of its successful operation in geostationary orbit. The SOXS mission onboard GSAT-2 Indian spacecraft was launched successfully by GSLV-D2 rocket on 08 May 2003 to study the energy release and particle acceleration in solar flares. The SOXS is composed of two independent payloads viz. SOXS Low Energy Detector (SLD) payload, and SOXS High Energy Detector (SHD) payload. We restrict our presentation to SLD payload that designed, developed and fabricated by Physical Research Laboratory (PRL) in collaboration with Space Application Centre (SAC), Ahmedabad and ISRO Satellite Centre (ISAC), Bangalore of Indian Space Research Organization (ISRO). We briefly present the scientific objectives and instrumentation of the SLD payload. The SLD payload employs the state-of-art solid state detectors viz. Si PIN and CZT detectors, which reveal sub-keV spectral and 100ms temporal resolution characteristics that are necessary to study the spectral response of the flare components. The dynamic range of Si and CZT detectors is 4-25 and 4-56 keV respectively. The SLD has observed more than 140 flares of C and M class since its commissioning in the orbit. We present the X-ray emission characteristics of a few typical flares in view of their spectral hardening and geo-effectiveness. We extend our study of these flares to optical and radio waveband observations in order to improve the relationship of X-ray spectral hardening and geo-effectiveness. The flares with harder spectra and associated with small or large CME, and radio emission at frequencies above 10 GHz are found geo-effective.

  20. Application of laser surface modiifcation technology in Titanium Alloys%激光表面改性技术在钛合金上的应用研究



    The surface treatment can effectively improve the performance of titanium and titanium aloys, surface hardening technology for titanium and titanium aloy provides a wider range of applications, and there are many new modification methods and processes are emerging. This paper focuses on laser surface modification technology in the titanium aloy were analyzed.%表面处理可以有效地提高钛及钛合金的性能,表面强化技术为钛及钛合金提供了更广泛的应用前景,并且有许多新的改性方法与工艺不断涌现。本文主要对激光表面改性技术在钛合金上的应用进行了分析研究。

  1. Quantitative analysis of artifacts in 4D DSA: the relative contributions of beam hardening and scatter to vessel dropout behind highly attenuating structures

    Hermus, James; Szczykutowicz, Timothy P.; Strother, Charles M.; Mistretta, Charles


    When performing Computed Tomographic (CT) image reconstruction on digital subtraction angiography (DSA) projections, loss of vessel contrast has been observed behind highly attenuating anatomy, such as dental implants and large contrast filled aneurysms. Because this typically occurs only in a limited range of projection angles, the observed contrast time course can potentially be altered. In this work, we have developed a model for acquiring DSA projections that models both the polychromatic nature of the x-ray spectrum and the x-ray scattering interactions to investigate this problem. In our simulation framework, scatter and beam hardening contributions to vessel dropout can be analyzed separately. We constructed digital phantoms with large clearly defined regions containing iodine contrast, bone, soft issue, titanium (dental implants) or combinations of these materials. As the regions containing the materials were large and rectangular, when the phantoms were forward projected, the projections contained uniform regions of interest (ROI) and enabled accurate vessel dropout analysis. Two phantom models were used, one to model the case of a vessel behind a large contrast filled aneurysm and the other to model a vessel behind a dental implant. Cases in which both beam hardening and scatter were turned off, only scatter was turned on, only beam hardening was turned on, and both scatter and beam hardening were turned on, were simulated for both phantom models. The analysis of this data showed that the contrast degradation is primarily due to scatter. When analyzing the aneurysm case, 90.25% of the vessel contrast was lost in the polychromatic scatter image, however only 50.5% of the vessel contrast was lost in the beam hardening only image. When analyzing the teeth case, 44.2% of the vessel contrast was lost in the polychromatic scatter image and only 26.2% of the vessel contrast was lost in the beam hardening only image.

  2. Experimental Study on the Milling of a Ti Beta 21S


    Ti Beta 21S (Ti-15Mo-2.7Nb-3Al-0.2Si) was devel op ed by TIMET in 1989. It is a metastable beta titanium alloy that offers subs tantial weight reductions over other engineering materials. Compared with common beta Ti alloys, it offers the high specific strength, good cold formability, im proved oxidation resistance, elevated temperature strength, creep resistance, an d thermal stability. Besides the common characters of titanium alloy, such as po or heat diffusivity, low elastic modulus, Ti Beta 21S has ...

  3. Work-hardening stages and deformation mechanism maps during tensile deformation of commercially pure titanium

    Becker, Hanka; Pantleon, Wolfgang


    by dislocation slip, in the following stage (for moderate stresses), an abundance of 64.6∘〈1¯010〉 twin boundaries form indicating the dominance of {112¯2}〈1¯1¯23〉 compression twinning. During the last stage before the onset of necking, additional 84.8∘〈112¯0〉 twin boundaries are detected caused by {101...

  4. Research on Deep Hardening Titanium Alloy for Large Airframe Structural Members. Volume 2


    om mowo moi oooo oo momo mm -*(n-*«* >» m a i ij a [! mm m oom om Om mm CMCM CM mor~ Or^ or>. Nf» mm m COCO CM vom m-* co^o mm O...vovo vo ooo vovo »om pHrHr-tp-l SSr-l i-tr-l r-i ZZZ t-t r-l r-l r-l «m Cr- 0\\o d m en u 3 <u n « s -1 H momo om mo m mmo mm mo (Nmr^o or

  5. Oxygen Permeation Behaviors and Hardening Effect of Titanium Alloys at High Temperature

    Hongyan MA; Maocai WANG; Weitao WU


    In order to improve the surface hardness and wear resistance of Ti and Ti alloy components, an oxygen permeationtreatment (OPT) was developed. The oxygen permeation behaviors of three Ti alloys, TA2, TB5 and TC11, treatedin air with O-P medium at high temperature have been studied. The results show that the O-P treatment cansignificantly improve the surface hardness of Ti alloys. The oxidation mass-gain of β-Ti alloy (TB5) is much higherthan α-Ti alloy (TA2) under the same condition, while α+β Ti alloy (TC11) is the lowest. All the Ti alloys treatedat this condition produce two surface layers: the outer layer consists mainly of TiO2, as well as trace of other oxides,and the inner layer consists of a Ti-O interstitial solid solution formed by the diffusion of oxygen in α crystal latticeThick scales of β Ti alloy (TB5) are easily formed depending mainly on the poor solid solution content of oxygen,while deep solution layer can be formed since partial β phase has been transformed into α phase. The scales of α-βTi alloy (TC11) are very thin and compact. Aluminum-rich zone, as well as deficient zone, is found in oxide layerrs.A crystallographic characterization of oxygen solution layer has been performed and evaluated by crystallographiclattice constant.

  6. Titanium metal: extraction to application

    Gambogi, Joseph (USGS, Reston, VA); Gerdemann, Stephen J.


    In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of rutile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium. In this paper, we discuss all aspects of the titanium industry from ore deposits through extraction to present and future applications. The methods of both primary (mining of ore, extraction, and purification) and secondary (forming and machining) operations will be analyzed. The chemical and physical properties of titanium metal will be briefly examined. Present and future applications for titanium will be discussed. Finally, the economics of titanium metal production also are analyzed as well as the advantages and disadvantages of various alternative extraction methods.

  7. Tailoring of Microstructure and Properties of Titanium Parts with Local Rapid Heat Treatment


    kinetics of Ti-6-4 and Ti6242 titanium alloys, Journal of Alloys and Compounds , 2001, 314, #1-2, pp. 181-191. [13] Ivasishin O.M. and Markovsky P.E...beta-titanium alloys, Journal of Alloys and Compounds , 2008, Volume 457, Issues 1-2, p. 296-309. [17] Troshchenko V.T., Ivasishin O.M., Gryaznov B.A

  8. Potential of rapid heat treatment of titanium alloys and steels

    Ivasishin, O.M.; Teliovich, R.V. [Institute of Metal Physics, Kiev (Ukraine)


    Rapid heat treatment (RHT) of titanium alloys and steels, which includes rapid heating into the single-phase field, {beta} and {gamma} of titanium alloys and steels, respectively, is reviewed. Heating rate is an important parameter that affects the mechanism and kinetics of phase and/or structural transformation. Refinement of grain structure, formation of micro-chemical inhomogeneity and substructure in the high temperature phase following RHT are addressed. Thermo-kinetic effects during rapid heating of material with an initial metastable (quenched or deformed) microstructure are discussed. The response of titanium alloys and steels to RHT is compared. The improvement in mechanical properties of both material system following RHT is also presented. (orig.) 48 refs.

  9. Surface modification of titanium and titanium alloys by ion implantation.

    Rautray, Tapash R; Narayanan, R; Kwon, Tae-Yub; Kim, Kyo-Han


    Titanium and titanium alloys are widely used in biomedical devices and components, especially as hard tissue replacements as well as in cardiac and cardiovascular applications, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. However, titanium and its alloys cannot meet all of the clinical requirements. Therefore, to improve the biological, chemical, and mechanical properties, surface modification is often performed. In view of this, the current review casts new light on surface modification of titanium and titanium alloys by ion beam implantation.

  10. Porosity and mechanically optimized PLGA based in situ hardening systems.

    Schloegl, W; Marschall, V; Witting, M Y; Volkmer, E; Drosse, I; Leicht, U; Schieker, M; Wiggenhorn, M; Schaubhut, F; Zahler, S; Friess, W


    Goal of the present study was to develop and to characterize in situ-hardening, porous PLGA-based systems for their future application as bone grafting materials. Therefore, we investigated the precipitation behavior of formulations containing PLGA and a water-miscible solvent, DMSO, PEG 400, and NMP. To increase porosity, a pore forming agent (NaCMC) was added and to enhance mechanical properties of the system, an inorganic filler (α-TCP) was incorporated. The behavior upon contact with water and the influence of the prior addition of aqueous media on the morphology of the corresponding hardened implants were investigated. We proved cell-compatibility by live/dead assays for the hardened porous polymer/ceramic-composite scaffolds. The IsHS formulations can therefore be used to manufacture hardened scaffolds ex vivo by using molds with the desired shape and size. Cells were further successfully incorporated into the IsHS by precultivating the cells on the α-TCP-powder prior to their admixing to the formulation. However, cell viability could not be maintained due to toxicity of the tested solvents. But, the results demonstrate that in vivo cells should well penetrate, adhere, and proliferate in the hardened scaffolds. Consequently, we consider the in situ hardening system being an excellent candidate as a filling material for non-weight-bearing orthopedic indications, as the resulting properties of the hardened implant fulfill indication-specific needs like mechanical stability, elasticity, and porosity.

  11. Tailored work hardening descriptions in simulation of sheet metal forming

    Vegter, Henk; Mulder, Hans.; van Liempt, Peter; Heijne, Jan


    In the previous decades much attention has been given on an accurate material description, especially for simulations at the design stage of new models in the automotive industry. Improvements lead to shorter design times and a better tailored use of material. It also contributed to the design and optimization of new materials. The current description of plastic material behaviour in simulation models of sheet metal forming is covered by a hardening curve and a yield surface. In this paper the focus will be on modelling of work hardening for advanced high strength steels considering the requirements of present applications. Nowadays work hardening models need to include the effect of hard phases in a soft matrix and the effect of strain rate and temperature on work hardening. Most material tests to characterize work hardening are only applicable to low strains whereas many practical applications require hardening data at relatively high strains. Therefore, physically based hardening descriptions are needed allowing reliable extensions to high strain values.

  12. Surface modification on PMMA : PVDF polyblend: hardening under chemical environment

    R Bajpai; V Mishra; Pragyesh Agrawal; S C Datt


    The influence of chemical environment on polymers include the surface alteration as well as other deep modifications in surface layers. The surface hardening, as an effect of organic liquids on poly(methyl methacrylate): poly(vinylidene fluoride) (PMMA: PVDF), which is one of the few known miscible blends, has been detected using microhardness testing. Organic liquids like acetone, toluene, xylene and benzene were introduced on the surface of blend specimens for different durations. Vickers microhardness (v) was measured for treated and untreated specimens. The study reveals both hardening and plasticization of specimens at different exposure times. The degree of surface hardening is maximum under acetone treatment. All the specimens exhibit surface hardening at an exposure time of 1 h with all the four liquids. This feature is prominent with longer exposures for specimens with increasing content of PVDF. However, the degree of hardening decreases with the time of exposure in the respective environments. In general, acetone and toluene impart surface hardening, whereas, xylene and benzene soften the specimen. PMMA: PVDF (83 : 17) blend exhibits surface hardening under all the four treatments when compared with the respective untreated specimens.


    LIUTeng-xi; HUANGShi-qing; FUYi-ming


    A dimensionless stress yield criterion is proposed to describe the mixed hardening of orthortropic material ,including kinematic hardening and proportional hardening,and the associated plastic flow law is derived.The generalized effective stress-strain formulae can be obtained correspondingly based on the experimental stress-strain curves in various simple stress states.The initial plastic anisotropy is influenced by the elastic anisotropy.The yield criterion can be reduced to Huber-Mises Criterion for isotropic materials and associated constitutive equations can be degenerated into Prandtl-Reuss equations.


    刘腾喜; 黄世清; 傅衣铭


    A dimensionless stress yield criterion is proposed to describe the mixed hardening of orthotropic material, including kinematic hardening and proportional hardening, and the associated plastic flow law is derived. The generalized effective stress-strain formulae can be obtained correspondingly based on the experimental stress-strain curves in various simple stress states. The initial plastic anisotropy is influenced by the elastic anisotropy. The yield criterion can be reduced to Huber-Mises Criterion for isotropic materials and associated constitutive equations can be degenerated into Prandtl-Reuss equations.

  15. Variations in the Bainite Hardenability of ASTM A723 Steel


    8217, ,- -’ . . • • . . . . -. . " . ,~ .. -- --. x n~ I]AD TECHNICAL REPORT ARCCB-TR-87012 VARIATIONS IN THE BAINITE U) HARDENABILITY OF ASTM A723 STEEL 0’) 00 PAUL J. COTE LAWRENCE V...rod ,SuDfll|m) S. ?YPl[ Off REPOR.r & Pl[RIOO COVER•O VARIATIONS IN THE; BAINITE HARDENABILITY OF Final ASTH A723 STEEL I. Pl[RFORMINQ ORO. REPORT...0.1%) and copper (0.1%) in A723. A key transformation characteristic for this alloy is the bainite hardenability. It is important to know the extent to

  16. Ceramic Conversion Treatment of Titanium Aluminide for Improved Tribological Properties

    JingXIA; ChenxiLI; HanshanDONG; TomBELL


    Gamma-based titanium aluminides have great potential in the automotive industries (e.g. valves in a car engine), but tribological property could be one of the crucial factors in determining the life and performance of a titanium aluminide part. A surface modification technique, namely ceramic conversion (CC) treatment has been developed to improve the tribological properties of a γ-based titanium aluminide (Ti-48A1-2Nb-2Cr-B), and the surface properties were fully characterised. The results indicate that ceramic conversion treatment can produce an oxide layer consisting of a top TiO2 surface followed by a mixture of TiO2 and Al2O3. Such hardened layer has significantly improved the load-bearing capacity and wear resistance of the intermetallics, as evidenced by an increase of scuffing load up to 4 times and a wear rate reduction of two orders of magnitude. The coefficient of friction has also been reduced from 0.5-0.7 for the untreated to an average of 0.22 for the CC-treated alloy under dry sliding contact conditions.

  17. Ceramic Conversion Treatment of Titanium Aluminide for Improved Tribological Properties

    Jing XIA; Chenxi LI; Hanshan DONG; Tom BELL


    Gamma-based titanium aluminides have great potential in the automotive industries (e.g. valves in a car engine),but tribological property could be one of the crucial factors in determining the life and performance of a titanium aluminide part. A surface modification technique, namely ceramic conversion (CC) treatment has been developed to improve the tribological properties of a γ-based titanium aluminide (Ti-48Al-2Nb-2Cr-B), and the surface properties were fully characterised. The results indicate that ceramic conversion treatment can produce an oxide layer consisting of a top TiO2 surface followed by a mixture of TiO2 and Al2O3. Such hardened layer has significantly improved the load-bearing capacity and wear resistance of the intermetallics, as evidenced by an increase of scuffing load up to 4 times and a wear rate reduction of two orders of magnitude. The coefficient of friction has also been reduced from 0.5-0.7 for the untreated to an average of 0.22 for the CC-treated alloy under dry sliding contact conditions.

  18. Titanium alloys in total joint replacement--a materials science perspective.

    Long, M; Rack, H J


    Increased use of titanium alloys as biomaterials is occurring due to their lower modulus, superior biocompatibility and enhanced corrosion resistance when compared to more conventional stainless steels and cobalt-based alloys. These attractive properties were a driving force for the early introduction of alpha (cpTi) and alpha + beta (Ti-6A1-4V) alloys as well as for the more recent development of new Ti-alloy compositions and orthopaedic metastable beta titanium alloys. The later possess enhanced biocompatibility, reduced elastic modulus, and superior strain-controlled and notch fatigue resistance. However, the poor shear strength and wear resistance of titanium alloys have nevertheless limited their biomedical use. Although the wear resistance of beta-Ti alloys has shown some improvement when compared to alpha + beta alloys, the ultimate utility of orthopaedic titanium alloys as wear components will require a more complete fundamental understanding of the wear mechanisms involved. This review examines current information on the physical and mechanical characteristics of titanium alloys used in artifical joint replacement prostheses, with a special focus on those issues associated with the long-term prosthetic requirements, e.g., fatigue and wear.

  19. Space Qualified, Radiation Hardened, Dense Monolithic Flash Memory Project

    National Aeronautics and Space Administration — Space Micro proposes to build a radiation hardened by design (RHBD) flash memory, using a modified version of our RH-eDRAM Memory Controller to solve all the single...

  20. Properties of sodium silicate bonded sand hardened by microwave heating

    Wang Jina; Fan Zitian; Zan Xiaolei; Pan Di


    The sodium silicate bonded sand hardened by microwave heating has many advantages,such as low sodium silicate adding quantity,fast hardening speed,high room temperature strength,good collapsibility and certain surface stability. However,it has big moisture absorbability in the air,which would lead to the compression strength and the surface stability of the sand molds being sharply reduced. In this study,the moisture absorbability of the sodium silicate bonded sand hardened by microwave heating in different humidity conditions and the effect factors were investigated. Meanwhile,the reasons for the big moisture absorbability of the sand were analyzed.Some measures to overcome the problems of high moisture absorbability,bad surface stability and sharply reducing strength in the air were discussed. The results of this study establish the foundation of green and clean foundry technology based on the microwave heating hardening sodium silicate sand process.

  1. Space Qualified, Radiation Hardened, Dense Monolithic Flash Memory Project

    National Aeronautics and Space Administration — Radiation hardened nonvolatile memories for space is still primarily confined to EEPROM. There is high density effective or cost effective NVM solution available to...

  2. Tensile Strain Hardening Behavior and Fractography of Superalloy GH39

    WANG Hui


    Full Text Available The strain hardening behaviour and fractography of superalloy GH39 was investigated by tensile test at different strain rates. Results indicate that strain hardening behaviours are different during the deformation process. True stress-strain curve obeys the Hollomon relationship partly. The strain hardening exponentn in this stage is constant in the initial plastic stage. However, the value of n increased with true strain ε increasing when true strain is between 0.014 and 0.13. A lot of deformation twinning can be found, the twins and dislocations worked together to increase the value of n. The strain hardening exponent is increased lightly with the strain rate increasing, SEM observations show that in the case of low strain rate, the fracture mode is typical ductile, but there is a tendency from ductile to brittle fracture with increasing the strain rate.

  3. Radiation Hardened Ethernet PHY and Switch Fabric Project

    National Aeronautics and Space Administration — Innoflight will develop a new family of radiation hardened (up to 3 Mrad(Si)), fault-tolerant, high data-rate (up to 8 Gbps), low power Gigabit Ethernet PHY and...

  4. Technologies Enabling Custom Radiation-Hardened Component Development Project

    National Aeronautics and Space Administration — Two primary paths are available for the creation of a Rad-Hard ASIC. The first approach is to use a radiation hardened process such as existing Rad-Hard foundries....

  5. Novel SEU hardened PD SOI SRAM cell

    Xie Chengmin; Wang Zhongfang; Wang Xihu; Wu Longsheng; Liu Youbao


    A novel SEU hardened 10T PD SOI SRAM cell is proposed.By dividing each pull-up and pull-down transistor in the cross-coupled inverters into two cascaded transistors,this cell suppresses the parasitic BJT and source-drain penetration charge collection effect in PD SOl transistor which causes the SEU in PD SOI SRAM.Mixed-mode simulation shows that this novel cell completely solves the SEU,where the ion affects the single transistor.Through analysis of the upset mechanism of this novel cell,SEU performance is roughly equal to the multiple-cell upset performance of a normal 6T SOI SRAM and it is thought that the SEU performance is 17 times greater than traditional 6T SRAM in 45nm PD SOI technology node based on the tested data of the references.To achieve this,the new cell adds four transistors and has a 43.4% area overhead and performance penalty.

  6. Durability of High Performance Color Hardener

    MA Bao-guo; DONG Rong-zhen; ZHU Hong-bo; ZHANG Li; JIAN Shou-wei


    The properties of high performance color hardener (HPCH) and the mechanism were studied.HPCH is a composite system, which is composed of cementitious and auxiliary cementing materials, composite additives, abrasion resistance component (aggregate) and pigment. The porosity and pore structure of the material are obviously improved due to the activation, filling and adsorption of auxiliary cementing materials, thus resulting in a great increase of binding capacity for ions in HPCH and the obstacles of ion migrating.The density of material structure, bonding capacity of cementitious material to the abrasion-resisting component and the corrosion resistance are greatly and effectively improved by adding the auxiliary cementing materials and compound additives. According to the tests of dry shrinkage, sulphate resistance, chloride permeability and Ca(OH)2 content distribution, the property superiority of HPCH is analyzed.The mechanism of materials modification of HPCH is explained from the microscopic point of view by testing the pore structure and pore distribution via the mercury intrusion pressure method.

  7. Open Source Radiation Hardened by Design Technology

    Shuler, Robert


    The proposed technology allows use of the latest microcircuit technology with lowest power and fastest speed, with minimal delay and engineering costs, through new Radiation Hardened by Design (RHBD) techniques that do not require extensive process characterization, technique evaluation and re-design at each Moore's Law generation. The separation of critical node groups is explicitly parameterized so it can be increased as microcircuit technologies shrink. The technology will be open access to radiation tolerant circuit vendors. INNOVATION: This technology would enhance computation intensive applications such as autonomy, robotics, advanced sensor and tracking processes, as well as low power applications such as wireless sensor networks. OUTCOME / RESULTS: 1) Simulation analysis indicates feasibility. 2)Compact voting latch 65 nanometer test chip designed and submitted for fabrication -7/2016. INFUSION FOR SPACE / EARTH: This technology may be used in any digital integrated circuit in which a high level of resistance to Single Event Upsets is desired, and has the greatest benefit outside low earth orbit where cosmic rays are numerous.

  8. Cylindrical shell buckling through strain hardening

    Bandyopadhyay, K.; Xu, J.; Shteyngart, S. [Brookhaven National Lab., Upton, NY (United States); Gupta, D. [USDOE, Germantown, MD (United States)


    Recently, the authors published results of plastic buckling analysis of cylindrical shells. Ideal elastic-plastic material behavior was used for the analysis. Subsequently, the buckling analysis program was continued with the realistic stress-strain relationship of a stainless steel alloy which does not exhibit a clear yield point. The plastic buckling analysis was carried out through the initial stages of strain hardening for various internal pressure values. The computer program BOSOR5 was used for this purpose. Results were compared with those obtained from the idealized elastic-plastic relationship using the offset stress level at 0.2% strain as the yield stress. For moderate hoop stress values, the realistic stress-grain case shows a slight reduction of the buckling strength. But, a substantial gain in the buckling strength is observed as the hoop stress approaches the yield strength. Most importantly, the shell retains a residual strength to carry a small amount of axial compressive load even when the hoop stress has exceeded the offset yield strength.

  9. Hardening in Two-Phase Materials. II. Plastic Strain and Mean Stress Hardening Rate

    Lilholt, Hans


    The strain parameters which are relevant in a tensile experiment, are analysed and related to the geometry of deformation and to the mean stress of two-phase materials. The hardening rate of the mean stress with respect to plastic strain is found to be useful in comparison between experiments and...... and theories, and it allows theories to be probed over a range of strains. Previous experiments on the fibre-reinforced material of copper-tungsten are analysed in relation to the geometry of deformation....

  10. Strain Hardening of Polymer Glasses: Entanglements, Energetics, and Plasticity

    Hoy, Robert S.; Robbins, Mark O.


    Simulations are used to examine the microscopic origins of strain hardening in polymer glasses. While stress-strain curves for a wide range of temperature can be fit to the functional form predicted by entropic network models, many other results are fundamentally inconsistent with the physical picture underlying these models. Stresses are too large to be entropic and have the wrong trend with temperature. The most dramatic hardening at large strains reflects increases in energy as chains are ...

  11. High strength microstructural forms developed in titanium alloys by rapid heat treatment

    Ivasishin, O.M. [Institute of Metal Physics, Kiev (Ukraine)


    It is shown that rapid heat treatment of alpha+beta and beta titanium alloys, which includes rapid heating of alloys with initial equiaxed microstructure into single-phase beta field is able to produce microstructural forms in which high strength can be well balanced with other mechanical properties. Main advantage of rapid heating approach comes from the possibility to extend the level of ''useful'' strength. Desirably high strength is provided by intragranular morphology and microchemistry while beta-grain refinement permits a reliability of such high strength conditions. (orig.)

  12. Extrinsic Hardening of Superhard Tungsten Tetraboride Alloys with Group 4 Transition Metals.

    Akopov, Georgiy; Yeung, Michael T; Turner, Christopher L; Mohammadi, Reza; Kaner, Richard B


    Alloys of tungsten tetraboride (WB4) with the group 4 transition metals, titanium (Ti), zirconium (Zr), and hafnium (Hf), of different concentrations (0-50 at. % on a metals basis) were synthesized by arc-melting in order to study their mechanical properties. The phase composition and purity of the as-synthesized samples were confirmed using powder X-ray diffraction (PXRD) and energy dispersive X-ray spectroscopy (EDS). The solubility limit as determined by PXRD is 20 at. % for Ti, 10 at. % for Zr, and 8 at. % for Hf. Vickers indentation measurements of WB4 alloys with 8 at. % Ti, 8 at. % Zr, and 6 at. % Hf gave hardness values, Hv, of 50.9 ± 2.2, 55.9 ± 2.7 and 51.6 ± 2.8 GPa, respectively, compared to 43.3 GPa for pure WB4 under an applied load of 0.49 N. Each of the aforementioned compositions are considered superhard (Hv > 40 GPa), likely due to extrinsic hardening that plays a key role in these superhard metal borides. Furthermore, these materials exhibit a significantly reduced indentation size effect, which can be seen in the plateauing hardness values for the W1-xZrxB4 alloy. In addition, W0.92Zr0.08B4, a product of spinoidal decomposition, possesses nanostructured grains and enhanced grain hardening. The hardness of W0.92Zr0.08B4 is 34.7 ± 0.65 GPa under an applied load of 4.9 N, the highest value obtained for any superhard metal at this relatively high loading. In addition, the WB4 alloys with Ti, Zr, and Hf showed a substantially increased oxidation resistance up to ∼460 °C, ∼510 °C, and ∼490 °C, respectively, compared to ∼400 °C for pure WB4.

  13. High-Performance, Radiation-Hardened Electronics for Space Environments

    Keys, Andrew S.; Watson, Michael D.; Frazier, Donald O.; Adams, James H.; Johnson, Michael A.; Kolawa, Elizabeth A.


    The Radiation Hardened Electronics for Space Environments (RHESE) project endeavors to advance the current state-of-the-art in high-performance, radiation-hardened electronics and processors, ensuring successful performance of space systems required to operate within extreme radiation and temperature environments. Because RHESE is a project within the Exploration Technology Development Program (ETDP), RHESE's primary customers will be the human and robotic missions being developed by NASA's Exploration Systems Mission Directorate (ESMD) in partial fulfillment of the Vision for Space Exploration. Benefits are also anticipated for NASA's science missions to planetary and deep-space destinations. As a technology development effort, RHESE provides a broad-scoped, full spectrum of approaches to environmentally harden space electronics, including new materials, advanced design processes, reconfigurable hardware techniques, and software modeling of the radiation environment. The RHESE sub-project tasks are: SelfReconfigurable Electronics for Extreme Environments, Radiation Effects Predictive Modeling, Radiation Hardened Memory, Single Event Effects (SEE) Immune Reconfigurable Field Programmable Gate Array (FPGA) (SIRF), Radiation Hardening by Software, Radiation Hardened High Performance Processors (HPP), Reconfigurable Computing, Low Temperature Tolerant MEMS by Design, and Silicon-Germanium (SiGe) Integrated Electronics for Extreme Environments. These nine sub-project tasks are managed by technical leads as located across five different NASA field centers, including Ames Research Center, Goddard Space Flight Center, the Jet Propulsion Laboratory, Langley Research Center, and Marshall Space Flight Center. The overall RHESE integrated project management responsibility resides with NASA's Marshall Space Flight Center (MSFC). Initial technology development emphasis within RHESE focuses on the hardening of Field Programmable Gate Arrays (FPGA)s and Field Programmable Analog

  14. The development of high strength corrosion resistant precipitation hardening cast steels

    Abrahams, Rachel A.

    Precipitation Hardened Cast Stainless Steels (PHCSS) are a corrosion resistant class of materials which derive their properties from secondary aging after a normalizing heat treatment step. While PHCSS materials are available in austenitic and semi-austenitic forms, the martensitic PHCSS are most widely used due to a combination of high strength, good toughness, and corrosion resistance. If higher strength levels can be achieved in these alloys, these materials can be used as a lower-cost alternative to titanium for high specific strength applications where corrosion resistance is a factor. Although wrought precipitation hardened materials have been in use and specified for more than half a century, the specification and use of PHCSS has only been recent. The effects of composition and processing on performance have received little attention in the cast steel literature. The work presented in these investigations is concerned with the experimental study and modeling of microstructural development in cast martensitic precipitation hardened steels at high strength levels. Particular attention is focused on improving the performance of the high strength CB7Cu alloy by control of detrimental secondary phases, notably delta ferrite and retained austenite, which is detrimental to strength, but potentially beneficial in terms of fracture and impact toughness. The relationship between age processing and mechanical properties is also investigated, and a new age hardening model based on simultaneous precipitation hardening and tempering has been modified for use with these steels. Because the CB7Cu system has limited strength even with improved processing, a higher strength prototype Fe-Ni-Cr-Mo-Ti system has been designed and adapted for use in casting. This prototype is expected to develop high strengths matching or exceed that of cast Ti-6Al-4V alloys. Traditional multicomponent constitution phase diagrams widely used for phase estimation in conventional stainless steels

  15. High-temperature Titanium Alloys

    A.K. Gogia


    Full Text Available The development of high-temperature titanium alloys has contributed significantly to the spectacular progress in thrust-to-weight ratio of the aero gas turbines. This paper presents anoverview on the development of high-temperature titanium alloys used in aero engines and potential futuristic materials based on titanium aluminides and composites. The role of alloychemistry, processing, and microstructure, in determining the mechanical properties of titanium alloys is discussed. While phase equilibria and microstructural stability consideration haverestricted the use of conventional titanium alloys up to about 600 "C, alloys based on TiPl (or,, E,AINb (0, TiAl (y, and titaniumltitanium aluminides-based composites offer a possibility ofquantum jump in the temperature capability of titanium alloys.

  16. Hydrolytically stable titanium-45

    Severin, Gregory; Fonslet, Jesper; Zhuravlev, Fedor


    Introduction Titanium-45, a candidate PET isotope, is under-employed largely because of the challenging aqueous chemistry of Ti(IV). The propensity for hydrolysis of Ti(IV) compounds makes radio-labeling difficult and excludes 45Ti from use in bio-conjugate chemistry. This is unfortunate because...... metal-based chemotherapeutics such as cisplatin. The aim of our work has been to produce the radioactive analogue of one of these Ti(IV)-salan compounds, Ti-salan-dipic [2], which has hydro-lytic stability on the order of weeks. Not only will this allow us to shed some light on the still un......-known mechanism of antiproliferative action of titanium-based chemotherapeutics, but it will also make progress toward bioconjugate 45Ti PET tracers. In the current abstract, we present some of the methods we are using to separate 45Ti from irradiated Sc, and subsequent labeling conditions. Material and Methods...

  17. Titanium Carbide: Nanotechnology, Properties, Application

    Galevsky, G. V.; Rudneva, V. V.; Garbuzova, A. K.; Valuev, Denis Viktorovich


    The paper develops scientific and technological bases for fabrication of titanium carbide which is a nanocomponent of composite materials. The authors determine optimum technology specifications and the main titanium carbide properties: fineness of titaniferous raw materials, carbide-forming agent quantity, set temperature of plasma flow, tempering temperature, titanium carbide yield, productivity, specific surface, size and shape of particles. The paper includes equations to describe how the...

  18. Titanium Nitride Cermets


    C ermets 7 Effect of Amount of Metal on Strength of TiN-Ni-Cr....26 Cerme ts S Effect of Amount of Metal on Strength of TiN-Co-Cr....27 Cermets 9...Figures 7 and 8. Titanium Nitride-Nickel-Chromium Cerme ts From Figure 7, it can be seen that 2900OF was the better firing temperature. The 20% metal

  19. Titanium Carbide: Nanotechnology, Properties, Application

    Galevsky, G. V.; Rudneva, V. V.; Garbuzova, A. K.; Valuev, D. V.


    The paper develops scientific and technological bases for fabrication of titanium carbide which is a nanocomponent of composite materials. The authors determine optimum technology specifications and the main titanium carbide properties: fineness of titaniferous raw materials, carbide-forming agent quantity, set temperature of plasma flow, tempering temperature, titanium carbide yield, productivity, specific surface, size and shape of particles. The paper includes equations to describe how the major specifications of the fabrication technique influence the content of titanium carbide and free carbon in the end product.

  20. Influence of Hardening Model on Weld Residual Stress Distribution

    Mullins, Jonathan; Gunnars, Jens (Inspecta Technology AB, Stockholm (Sweden))


    This study is the third stage of a project sponsored by the Swedish Radiation Safety Authority (SSM) to improve the weld residual stress modelling procedures currently used in Sweden. The aim of this study was to determine which material hardening model gave the best agreement with experimentally measured weld residual stress distributions. Two girth weld geometries were considered: 19mm and 65mm thick girth welds with Rin/t ratios of 10.5 and 2.8, respectively. The FE solver ABAQUS Standard v6.5 was used for analysis. As a preliminary step some improvements were made to the welding simulation procedure used in part one of the project. First, monotonic stress strain curves and a mixed isotropic/kinematic hardening model were sourced from the literature for 316 stainless steel. Second, more detailed information was obtained regarding the geometry and welding sequence for the Case 1 weld (compared with phase 1 of this project). Following the preliminary step, welding simulations were conducted using isotropic, kinematic and mixed hardening models. The isotropic hardening model gave the best overall agreement with experimental measurements; it is therefore recommended for future use in welding simulations. The mixed hardening model gave good agreement for predictions of the hoop stress but tended to under estimate the magnitude of the axial stress. It must be noted that two different sources of data were used for the isotropic and mixed models in this study and this may have contributed to the discrepancy in predictions. When defining a mixed hardening model it is difficult to delineate the relative contributions of isotropic and kinematic hardening and for the model used it may be that a greater isotropic hardening component should have been specified. The kinematic hardening model consistently underestimated the magnitude of both the axial and hoop stress and is not recommended for use. Two sensitivity studies were also conducted. In the first the effect of using a

  1. Reduction of work hardening rate in low-carbon steels

    Yalamanchili, Bhaskar Rao

    Low carbon grades of steel rods are used to produce finished products such as fine wire, coat hangers, staples, and roofing nails. These products are subject to ductility failures during production due to excessively high work hardening rates during wire drawing. The high work hardening rates are attributed to the presence of residuals, free nitrogen, or combinations thereof. This research concludes that the most cost-effective way to reduce the work hardening rate during wire drawing is to combine boron with nitrogen to form boron nitride, and thus reducing its work hardening contribution. The results of this study also conclude the following: (1) Boron/Nitrogen ratio is the more significant factor than rod tensile strength, which affects work hardening rate. Higher ratio is better in the 0.79 to 1.19 range. (2) Maintaining this narrow B/N range requires precise process control. (3) Process conditions such as dissolved oxygen (Steel Texas (North Star) benefited from this research by being able to provide a competitive edge in both quality and cost of its low carbon boron grades thus making North Star a preferred supplier of wire rod for these products.

  2. Cryptographic Path Hardening: Hiding Vulnerabilities in Software through Cryptography

    Ganesh, Vijay; Rinard, Martin


    We propose a novel approach to improving software security called Cryptographic Path Hardening, which is aimed at hiding security vulnerabilities in software from attackers through the use of provably secure and obfuscated cryptographic devices to harden paths in programs. By "harden" we mean that certain error-checking if-conditionals in a given program P are replaced by equivalent" we mean that adversaries cannot use semi-automatic program analysis techniques to reason about the hardened program paths and thus cannot discover as-yet-unknown errors along those paths, except perhaps through black-box dictionary attacks or random testing (which we can never prevent). Other than these unpreventable attack methods, we can make program analysis aimed at error-finding "provably hard" for a resource-bounded attacker, in the same sense that cryptographic schemes are hard to break. Unlike security-through-obscurity, in Cryptographic Path Hardening we use provably-secure crypto devices to hide errors and our mathemati...

  3. General Friction Model Extended by the Effect of Strain Hardening

    Nielsen, Chris V.; Martins, Paulo A.F.; Bay, Niels


    An extension to the general friction model proposed by Wanheim and Bay [1] to include the effect of strain hardening is proposed. The friction model relates the friction stress to the fraction of real contact area by a friction factor under steady state sliding. The original model for the real co...... of friction in metal forming, where the material generally strain hardens. The extension of the model to cover strain hardening materials is validated by comparison to previously published experimental data.......An extension to the general friction model proposed by Wanheim and Bay [1] to include the effect of strain hardening is proposed. The friction model relates the friction stress to the fraction of real contact area by a friction factor under steady state sliding. The original model for the real......-ideally plastic material, and secondly, to extend the solution by the influence of material strain hardening. This corresponds to adding a new variable and, therefore, a new axis to the general friction model. The resulting model is presented in a combined function suitable for e.g. finite element modeling...

  4. Chemical changes of titanium and titanium dioxide under electron bombardment

    Romins Brasca; Luciana Ines Vergara; Mario César Guillermo Passeggi; Julio Ferrón


    The electron induced effect on the first stages of the titanium (Ti0) oxidation and titanium dioxide (Ti4+) chemical reduction processes has been studied by means of Auger electron spectroscopy. Using factor analysis we found that both processes are characterized by the appearance of an intermediate Ti oxidation state, Ti2O3 (Ti3+).

  5. Plasmonic Titanium Nitride Nanostructures via Nitridation of Nanopatterned Titanium Dioxide

    Guler, Urcan; Zemlyanov, Dmitry; Kim, Jongbum


    Plasmonic titanium nitride nanostructures are obtained via nitridation of titanium dioxide. Nanoparticles acquired a cubic shape with sharper edges following the rock-salt crystalline structure of TiN. Lattice constant of the resulting TiN nanoparticles matched well with the tabulated data. Energ...

  6. Chemical changes of titanium and titanium dioxide under electron bombardment

    Romins Brasca


    Full Text Available The electron induced effect on the first stages of the titanium (Ti0 oxidation and titanium dioxide (Ti4+ chemical reduction processes has been studied by means of Auger electron spectroscopy. Using factor analysis we found that both processes are characterized by the appearance of an intermediate Ti oxidation state, Ti2O3 (Ti3+.

  7. Electron microscopy studies of the age-hardening behaviors in 6005A alloy and microstructural characterizations of precipitates

    Yang Wenchao, E-mail: [EPSRC Centre for Innovative Manufacturing in Liquid Metal Engineering, Brunel Centre for Advanced Solidification Technology (BCAST), Brunel University, Uxbridge, Middlesex UB8 3PH (United Kingdom); School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Huang Lanping [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Zhang Ruirong [School of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Wang Mingpu; Li Zhou; Jia Yanlin; Lei Ruoshan; Sheng Xiaofei [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)


    Highlights: Black-Right-Pointing-Pointer TEM and HREM are used to elucidate an anti overaged softening behavior in Al-0.65Mg-0.73Si-0.13Cu alloy. Black-Right-Pointing-Pointer The {beta} Double-Prime precipitate not only has a 2-dimensions coherency strain-field, but also has the smaller size and a high density. Black-Right-Pointing-Pointer The strengthening of three main precipitates on alloy can be summarized as: {beta} Double-Prime > Q Prime > {beta} Prime . Black-Right-Pointing-Pointer The {beta} Double-Prime , {beta} Prime and Q Prime precipitates have 12 orientation variants with Al matrix, respectively. Black-Right-Pointing-Pointer Moire fringes are used to verify the lattice parameters and orientation variants of precipitates. - Abstract: High-resolution electron microscopy was used to research the age-hardening behaviors in 6005A alloy and the microstructural characterizations of precipitates. It was found that {beta} Double-Prime , {beta} Prime and Q Prime precipitates had 12 orientation variants, respectively, the smaller size and a high-density {beta} Prime Prime precipitates existed in alloy for a long time, which played a very important role in controlling an anti-overaged softening behavior in 6005A alloy. Further, by the crystallographic interface and morphology analysis, a main reason was that a 2-dimensions coherency strain-field not only had the high-density {beta} Prime Prime precipitates become the biggest obstacle of dislocations movement, but also made them transform into {beta} Prime and Q Prime precipitates with more difficulty. Moreover, it was also found that {beta} Prime and Q Prime precipitates had weaker relatively strain-fields, the larger size and a lower density, which were largely associated with the reduction in hardness that occurred upon overaging. Further, the strengthening of precipitates on alloys could be summarized as: {beta} Double-Prime > Q Prime > {beta} Prime . Based on the structural information, the quantitative Moire


    Wei-Dan Ding,


    Full Text Available This study examines the dimensional stability of fast-growing poplar clones wood after treatment by impregnation with methyl methacrylate (MMA. Six hybrid poplar clones from one plantation in Quebec were sampled. The effects of hardening with MMA on density as well as longitudinal, radial, tangential, and volumetric swelling properties (S, water uptake capacity (D, anti-swelling efficiency (ASE, and water repellent efficiency (WRE after soaking were investigated. Hardening treatment increased the density of all poplar woods by 1.2 to 1.6 and decreased the inner water migration rate during soaking. S and D values of hardened woods were significantly lower than those of controls, depending on the clone type. ASE and WRE values suggested that incorporating MMA effectively improved the dimensional stability of poplar wood at the early soaking stage, but was less effective in the long term.

  9. Ion-irradiation-induced hardening in Inconel 718

    Hunn, J. D.; Lee, E. H.; Byun, T. S.; Mansur, L. K.


    Inconel 718 is a material under consideration for areas in the target region of the spallation neutron source (SNS), now under construction at Oak Ridge National Laboratory (ORNL) in the US. In these positions, displacement damage from protons and neutrons will affect the mechanical properties. In addition, significant amounts of helium and hydrogen will build up in the material due to transmutation reactions. Nanoindentation measurements of solution-annealed (SA) Inconel 718 specimens, implanted with Fe-, He-, and H-ions to simulate SNS target radiation conditions, have shown that hardening occurs due to ion-induced displacement damage as well as due to the build-up of helium bubbles in the irradiated layer. Precipitation-hardened (PH) Inconel 718 also exhibited hardening by helium build-up but showed softening as a function of displacement damage due to dissolution of the γ ' and γ″ precipitates.

  10. Surface hardening of steel in a solar furnace

    Rodriguez, G.P. [UCLM, ETSII, Ciudad Real (Spain); Damborenea, J.J. de [CENIM-CSIC, Madrid (Spain); Vazquez, A.J. [CENIM-CSIC, Madrid (Spain)


    The concentration of solar energy provides the possibility to get power densities high enough to produce surface modifications of materials, with low environmental impact. The present paper discusses the possibilities of surface hardening steel by means of concentrated solar energy. Surface treatments have been made by using the solar furnace of the Platafoma Solar in Almeria (Spain), which consists of a group of heliostats and a parabolic mirror. The surface transformation hardening treatment was performed on a 40CrMo4 steel. The paper presents the microstructural changes and the hardness values obtained after the solar treatment in a superficial zone. According to the power density applied on the sample, the hardened zone varied between 1 and 10 mm deep and the treatment time was less than 30 s. (orig.)

  11. Influence of coolant motion on structure of hardened steel element

    A. Kulawik


    Full Text Available Presented paper is focused on volumetric hardening process using liquid low melting point metal as a coolant. Effect of convective motion of the coolant on material structure after hardening is investigated. Comparison with results obtained for model neglecting motion of liquid is executed. Mathematical and numerical model based on Finite Element Metod is described. Characteristic Based Split (CBS method is used to uncouple velocities and pressure and finally to solve Navier-Stokes equation. Petrov-Galerkin formulation is employed to stabilize convective term in heat transport equation. Phase transformations model is created on the basis of Johnson-Mehl and Avrami laws. Continuous cooling diagram (CTPc for C45 steel is exploited in presented model of phase transformations. Temporary temperatures, phases participation, thermal and structural strains in hardening element and coolant velocities are shown and discussed.


    Yusuf ŞAHİN


    Full Text Available The investigation of machining AISI 1050 carbon steels hardened to the 60 HRC hardness was carried out to determine the tool life and wear behaviour of the various cutting tools under different conditions. These experiments were conducted at using coated ceramic cutting tools and carbide cutting tools. The experimental results showed that the coated ceramic tools exhibited better performance than those of the coated carbide tools when machining the hardened steels. Moreover, wear behaviour of cutting tools were investigated in a scanning electron microscope. Electron microscopic examination also indicated that flank wear, thermal cracks on the tool nose combined with the nose deformation on the tools were responsible for the wear behaviour of the ceramic tools. For the carbide tools, however, removal of coated material from the substrate tool and combined with the crater wear were effective for the machining the hardened steel.

  13. Stress field near an interface edge of linear hardening materials

    许金泉; 付列东


    The elastic-plastic singular stress field near an interface edge of bounded linear hardening material is substantially as same as that of bonded elastic materials whose Young' s modulus and Poisson ratio are substituted by equivalent values, respectively. Further investigation by the elasto-plastic boundary element method (BEM) on the stress field near the interface edge showed that the stress field there can be divided into three regions: the domain region of the elastic-plastic singular stress field, the transitional region and the elastic region. The domain region of the elastic-plastic singular stress becomes larger with the increasing of the linear hardening coefficient. When the linear hardening coefficient decreases to a certain value, the effective stress in most of the yield zone equals approximately the yield stress. The stress distribution in the elastic region under small-scale yielding condition was also investigated.

  14. Stress field near an interface edge of linear hardening materials


    The elastic-plastic singular stress field near an interface edge of bounded linear hardening material is substantially as same as that of bonded elastic materials whose Young's modulus and Poisson ratio are substituted by equivalent values, respectively. Further investigation by the elasto-plastic boundary element method (BEM) on the stress field near the interface edge showed that the stress field there can be divided into three regions: the domain region of the elastic-plastic singular stress field, the transitional region and the elastic region. The domain region of the elastic-plastic singular stress becomes larger with the increasing of the linear hardening coefficient. When the linear hardening coefficient decreases to a certain value, the effective stress in most of the yield zone equals approximately the yield stress. The stress distribution in the elastic region under small-scale yielding condition was also investigated.

  15. Cytokine and Eicosanoid Production by Cultured Human Monocytes Exposed to Titanium Particulate Debris

    Robinson, Timothy M.; Manley, Paul A.; Sims, Paul A.; Albrecht, Ralph; Darien, Benjamin J.


    Phagocytosis of particulate wear debris from arthroplasties by macrophages induces an inflammatory response that has been linked to implant loosening and premature failure of artificial joints. Inflammatory mediators released by phagocytic macrophages such as tumor necrosis factor-a (TNF-[alpha]), interleukin-1[beta] (IL-1[beta]), interleukin-6 (IL-6), and prostaglandin E2 (PGE2) are believed to play a central role in the pathogenesis of aseptic loosening. The objective of this study was to characterize titanium alloy particulates that closely match wear debris found around joint arthroplasties and to study their effects on the biosynthesis of inflammatory mediators by cultured monocytes. Peripheral blood monocytes were isolated from healthy human volunteers. Monocytes were cultured in 96-well plates for 24 h, washed, and exposed to three concentrations of titanium particulates and controls from 18Ð24 h. Supernatants were assayed for TNF-[alpha], IL-1[beta], IL-6, and PGE2 activity. Energy dispersive X-ray spectroscopy (EDX) verified the titanium alloy to be Ti6A14V. Scanning electron microscopy (SEM) analysis showed significant titanium particulate heterogeneity with approximately 95% of the particles TNF-[alpha], IL-1[beta], and PGE2.

  16. CT metal artifact reduction method correcting for beam hardening and missing projections

    Verburg, Joost M.; Seco, Joao


    We present and validate a computed tomography (CT) metal artifact reduction method that is effective for a wide spectrum of clinical implant materials. Projections through low-Z implants such as titanium were corrected using a novel physics correction algorithm that reduces beam hardening errors. In the case of high-Z implants (dental fillings, gold, platinum), projections through the implant were considered missing and regularized iterative reconstruction was performed. Both algorithms were combined if multiple implant materials were present. For comparison, a conventional projection interpolation method was implemented. In a blinded and randomized evaluation, ten radiation oncologists ranked the quality of patient scans on which the different methods were applied. For scans that included low-Z implants, the proposed method was ranked as the best method in 90% of the reviews. It was ranked superior to the original reconstruction (p = 0.0008), conventional projection interpolation (p implants, and better as compared to the original reconstruction (p combining algorithms tailored to specific types of implant materials.

  17. Precipitation hardening and microstructure evolution of the Ti-7Nb-10Mo alloy during aging.

    Yi, Ruowei; Liu, Huiqun; Yi, Danqing; Wan, Weifeng; Wang, Bin; Jiang, Yong; Yang, Qi; Wang, Dingchun; Gao, Qi; Xu, Yanfei; Tang, Qian


    A biomedical β titanium alloy (Ti-7Nb-10Mo) was designed and prepared by vacuum arc self-consumable melting. The ingot was forged and rolled to plates, followed by quenching and aging. Age-hardening behavior, microstructure evolution and its influence on mechanical properties of the alloy during aging were investigated, using X-ray diffraction, transmission electron microscopy, tensile and hardness measurements. The electrochemical behavior of the alloy was investigated in Ringer's solution. The microstructure of solution-treated (ST) alloy consists of the supersaturated solid solution β phase and the ωath formed during athermal process. The ST alloy exhibits Young's modulus of 80 GPa, tensile strength of 774 MPa and elongation of 20%. The precipitation sequences during isothermal aging at different temperatures were determined as β+ωath→β+ωiso (144 h) at Taging=350-400 °C, β+ωath→β+ωiso+α→β+α at Taging=500°C, and β+ωath→β+α at Taging=600-650 °C, where ωiso forms during isothermal process. The mechanical properties of the alloy can be tailored easily through controlling the phase transition during aging. Comparing with the conventional Ti-6Al-4V alloy, the Ti-7Nb-10Mo alloy is more resistant to corrosion in Ringer's solution. Results show that the Ti-7Nb-10Mo alloy is promising for biomedical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Titanium dioxide nanotube films

    Roman, Ioan, E-mail: [S.C. METAV-Research and Development S.R.L., Bucharest, 31C. A. Rosetti, 020011 (Romania); Trusca, Roxana Doina; Soare, Maria-Laura [S.C. METAV-Research and Development S.R.L., Bucharest, 31C. A. Rosetti, 020011 (Romania); Fratila, Corneliu [Research and Development National Institute for Nonferrous and Rare Metals, Pantelimon, 102 Biruintei, 077145 (Romania); Krasicka-Cydzik, Elzbieta [University of Zielona Gora, Department of Biomedical Engineering Division, 9 Licealna, 65-417 (Poland); Stan, Miruna-Silvia; Dinischiotu, Anca [University of Bucharest, Department of Biochemistry and Molecular Biology, 36-46 Mihail Kogalniceanu, 050107 (Romania)


    Titania nanotubes (TNTs) were prepared by anodization on different substrates (titanium, Ti6Al4V and Ti6Al7Nb alloys) in ethylene glycol and glycerol. The influence of the applied potential and processing time on the nanotube diameter and length is analyzed. The as-formed nanotube layers are amorphous but they become crystalline when subjected to subsequent thermal treatment in air at 550 °C; TNT layers grown on titanium and Ti6Al4V alloy substrates consist of anatase and rutile, while those grown on Ti6Al7Nb alloy consist only of anatase. The nanotube layers grown on Ti6Al7Nb alloy are less homogeneous, with supplementary islands of smaller diameter nanotubes, spread across the surface. Better adhesion and proliferation of osteoblasts was found for the nanotubes grown on all three substrates by comparison to an unprocessed titanium plate. The sensitivity towards bovine alkaline phosphatase was investigated mainly by electrochemical impedance spectroscopy in relation to the crystallinity, the diameter and the nature of the anodization electrolyte of the TNT/Ti samples. The measuring capacity of the annealed nanotubes of 50 nm diameter grown in glycerol was demonstrated and the corresponding calibration curve was built for the concentration range of 0.005–0.1 mg/mL. - Highlights: • Titania nanotubes (TNTs) on Ti, Ti6Al4V and Ti6Al7Nb substrates were prepared. • Quantitative dependences of anodization conditions on TNT features were established. • Morphology and electrochemical tests revealed inhomogeneity of TNT/Ti6Al7Nb films. • Particular characteristics of TNT films induce electrochemical sensitivity to ALP. • Annealed TNT/Ti impedimetric sensitivity towards ALP was demonstrated and quantified.


    E. P. Baradyntseva


    Full Text Available The research conducted in laboratory of metallurgical science by which the factors exerting impact on hardenability of steel microalloyed by boron were analysed. The research was made because the implementation of this process in mass production is connected with the certain difficulties. The conducted researches have allowed to draw a conclusion that changing content of various chemical elements, such as nitrogen, boron, the titan and aluminum in steel containing boron, produced by JSC «BSW – Management Company of Holding «BMC» at the stage of preparation of chart flowsheet make it possible to predict terms of hardenability of the final product.

  20. Aspect-oriented security hardening of UML design models

    Mouheb, Djedjiga; Pourzandi, Makan; Wang, Lingyu; Nouh, Mariam; Ziarati, Raha; Alhadidi, Dima; Talhi, Chamseddine; Lima, Vitor


    This book comprehensively presents a novel approach to the systematic security hardening of software design models expressed in the standard UML language. It combines model-driven engineering and the aspect-oriented paradigm to integrate security practices into the early phases of the software development process. To this end, a UML profile has been developed for the specification of security hardening aspects on UML diagrams. In addition, a weaving framework, with the underlying theoretical foundations, has been designed for the systematic injection of security aspects into UML models. The

  1. Laser hardening processing on tool steel SKD61



    This paper is aimed at overcoming different degree defects of crystalline structure in SKD61 carbide tool steel under quenching in solid phase and liquid phase. The paper studies the micro-structure and properties of laser strengthening SKD61 by using the method of laser hardening on the rein-forcement to improve the wear resistance of SKD61 . The results showed that the laser strengthening meth-od can improve the wear resistance of SKD61 . The study can provide reference for laser hardening metal materials.

  2. Diffusive Origin of the Cosmic-Ray Spectral Hardening

    Tomassetti, N


    Recent data from ATIC, CREAM and PAMELA revealed that the energy spectra of cosmic ray (CR) nuclei above 100 GeV/nucleon experience a remarkable hardening with increasing energy. This effect cannot be recovered by the conventional descriptions of CR acceleration and diffusive propagation processes. Using analytical calculations, I show that the hardening effect can be consequence of a spatial change of the CR diffusion properties in different regions of the Galaxy. I discuss the implications of this scenario for the main CR observables and its connections with the open issues of the CR physics.

  3. Microstructure and properties of cast iron after laser surface hardening



    Full Text Available Laser surface hardening of cast iron is not trivial due to the material’s heterogeneity and coarse-grained microstructure, particularly in massive castings. Despite that, hardening of heavy moulds for automotive industry is in high demand. The present paper summarises the findings collected over several years of study of materials structure and surface properties. Phase transformations in the vicinity of graphite are described using examples from production of body parts in automotive industry. The description relates to formation of martensite and carbide-based phases, which leads to hardness values above 65 HRC and to excellent abrasion resistance.


    P. V. Voronov


    Full Text Available Problem statement. Kinetic processes are of huge importance when producing building units and operating them as well. However, both technological and operation parameters are determined by the structure of a material under study.Results and conclusions. Kinetics with asymptotic approximation at hardening of building materials is analyzed. The validity of use of new kinetic equation is proved, characterizing harden composite systems and taking into consideration structural and topological peculiarities of new solid-like phase formation directly effecting the evolution of the processes. Results of research of change of strength at solidification a cement-sandy solution with various additives are submitted.

  5. Radiation Hardened 10BASE-T Ethernet Physical Layer (PHY)

    Lin, Michael R. (Inventor); Petrick, David J. (Inventor); Ballou, Kevin M. (Inventor); Espinosa, Daniel C. (Inventor); James, Edward F. (Inventor); Kliesner, Matthew A. (Inventor)


    Embodiments may provide a radiation hardened 10BASE-T Ethernet interface circuit suitable for space flight and in compliance with the IEEE 802.3 standard for Ethernet. The various embodiments may provide a 10BASE-T Ethernet interface circuit, comprising a field programmable gate array (FPGA), a transmitter circuit connected to the FPGA, a receiver circuit connected to the FPGA, and a transformer connected to the transmitter circuit and the receiver circuit. In the various embodiments, the FPGA, transmitter circuit, receiver circuit, and transformer may be radiation hardened.

  6. Effect on Hydration and Hardening of Tricalcium Phosphate Bone Cement


    The bioactive α-Ca3 (PO4)2 bone cement was studied by XRD , SEM and isothermal calorimetric measurements. The results showed that a mixed pattern of TCP and hydroxylapatite were obtained after hydration and hardening. The mechanism of hydration and hardening of the α-Ca3 ( PO4 )2 was dissolution-precipitation,(NH4) H2 PO4 was the best set accelerator to the α-Ca3 ( PO4 )2 cement, and the HAP powers and the(NH4) H2 PO4 concentration had a great effect on the hydration rate of α-Ca3 ( PO4 )2.

  7. Temperature Development during Hardening of Large Concrete Cubes

    Sørensen, Eigil V.; Burcharth, Hans Falk

    The purpose ofthe project is to verify ifthermal cracking will occur in large unreinforced concrete cubes due to large temperature differences during hardening o f the concrete. The first part o f the project is to numerically simulate the temperature development during hardening, evaluate the risk...... of thermally induced crackingunder varying execution conditions, and verify the temperature calculations by caJTying out measurements in situ. The cubes are cast and cured under marine environmental conditions in the north western part of Spain and are to serve as coastal proteetion in a harbour under...

  8. Temperature Development during Hardening of Large Concrete Cubes

    Sørensen, Eigil V.; Burcharth, Hans Falk

    The purpose ofthe project is to verify ifthermal cracking will occur in large unreinforced concrete cubes due to large temperature differences during hardening o f the concrete. The first part o f the project is to numerically simulate the temperature development during hardening, evaluate the risk...... of thermally induced cracking under varying execution conditions, and verify the temperature calculations by carrying out measurements in situ. The cubes are cast and cured under marine environmental conditions in the north western part of Spain and are to serve as coastal proteetion in a harbour under...

  9. Impact of Scaled Technology on Radiation Testing and Hardening

    LaBel, Kenneth A.; Cohn, Lewis M.


    This presentation gives a brief overview of some of the radiation challenges facing emerging scaled digital technologies with implications on using consumer grade electronics and next generation hardening schemes. Commercial semiconductor manufacturers are recognizing some of these issues as issues for terrestrial performance. Looking at means of dealing with soft errors. The thinned oxide has indicated improved TID tolerance of commercial products hardened by "serendipity" which does not guarantee hardness or say if the trend will continue. This presentation also focuses one reliability implications of thinned oxides.

  10. Temperature influence on water transport in hardened cement pastes

    Drouet, Emeline [CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, F-91191 Gif sur Yvette Cedex (France); Poyet, Stéphane, E-mail: [CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, F-91191 Gif sur Yvette Cedex (France); Torrenti, Jean-Michel [Université Paris-Est, IFSTTAR, Département Matériaux & Structures, 14-52 boulevard Newton, F-77447 Marne la Vallée cedex 2 (France)


    Describing water transport in concrete is an important issue for the durability assessment of radioactive waste management reinforced concrete structures. Due to the waste thermal output such structures would be submitted to moderate temperatures (up to 80 °C). We have then studied the influence of temperature on water transport within hardened cement pastes of four different formulations. Using a simplified approach (describing only the permeation of liquid water) we characterized the properties needed to describe water transport (up to 80 °C) using dedicated experiments. For each hardened cement paste the results are presented and discussed.

  11. A rapid cold-hardening process in insects.

    Lee, R E; Chen, C P; Denlinger, D L


    Traditionally studies of cold tolerance in insects have focused on seasonal adaptations related to overwintering that are observed after weeks or months of exposure to low temperature. In contrast, an extremely rapid cold-hardening response was observed in nonoverwintering stages that confers protection against injury due to cold shock at temperatures above the supercooling point. This response was observed in nondiapausing larvae and pharate adults of the flesh fly, Sarcophaga crassipalpis, nondiapausing adults of the elm leaf beetle, Xanthogaleruca luteola, and the milkweed bug, Oncopeltus fasciatus. The rapid hardening response is correlated with the accumulation of glycerol.

  12. Design of new titanium alloys for orthopaedic applications.

    Guillemot, F; Prima, F; Bareille, R; Gordin, D; Gloriant, T; Porté-Durrieu, M C; Ansel, D; Baquey, Ch


    Parallel to the biofunctionalisation of existing materials, innovation in biomaterials engineering has led to the specific design of titanium alloys for medical applications. Studies of the biological behaviour of metallic elements have shown that the composition and structure of the material should be carefully tailored to minimise adverse body reactions and to enhance implant longevity, respectively. Consequently, interest has focused on a new family of titanium alloys: Ti-6Mo-3Fe-5Ta, Ti-4Mo-2Fe-5Ta and Ti-6Mo-3Fe-5Zr-5Hf alloys. The non-toxicity of the specially designed titanium alloys compared with osteoblastic cells has been ascertained using MTT and RN tests. In addition, phase transformations upon thermal processing have been investigated, with comparison with a well-defined beta titanium alloy. Optimum thermal processing windows (above 550 degrees C) have been designed to generate a stable and nanostructured alpha phase from the isothermal omega phase that precipitates in a low temperature range (150-350 degrees C). The generation of such nanostructured microstructures should provide a promising opportunity to investigate tissue-biomaterial interactions at the scale of biomolecules such as proteins.

  13. Environmental protection to 922K (1200 F) for titanium alloys

    Groves, M. T.


    Evaluations are presented of potential coating systems for protection of titanium alloys from hot-salt stress-corrosion up to temperatures of 755 K (900 F) and from oxidation embrittlement up to temperature of 922 K (1200 F). Diffusion type coatings containing Si, Al, Cr, Ni or Fe as single coating elements or in various combinations were evaluated for oxidation protection, hot-salt stress-corrosion (HSSC) resistance, effects on tensile properties, fatigue properties, erosion resistance and ballistic impact resistance on an alpha and beta phase titanium alloy (Ti-6Al-2Sn-4Zr-2Mo). All of the coatings investigated demonstrated excellent oxidation protectiveness, but none of the coatings provided protection from hot-salt stress-corrosion. Experimental results indicated that both the aluminide and silicide types of coatings actually decreased the HSSC resistance of the substrate alloy. The types of coatings which have typically been used for oxidation protection of refractory metals and nickel base superalloys are not suitable for titanium alloys because they increase the susceptibility to hot-salt stress-corrosion, and that entirely new coating concepts must be developed for titanium alloy protection in advanced turbine engines.


    Mangini, Colby D; Hamby, David M


    Scaling of dose-point kernel (DPK) values for beta particles transmitted by high-Z sources will overestimate dose at shallow depths while underestimating dose at greater depths due to spectral hardening. A new model has been developed based on a determination of the amount of monoenergetic electron absorption that occurs in a given source thickness through the use of EGSnrc (Electron Gamma Shower) Monte Carlo simulations. Integration over a particular beta spectrum provides the beta-particle DPK following self-absorption as a function of source thickness and radial depth in water, thereby accounting for spectral hardening that may occur in higher-Z materials. Beta spectra of varying spectral shapes and endpoint energies were used to test the model for select source materials with 7.42 ≤ Z ≤ 94. The results demonstrate that significant improvements can be made to DPK-based dosimetry models when dealing with high-Z volumetric sources. This new scaling model is currently being used to improve the accuracy of the beta-dosimetry calculations in VARSKIN 5.

  15. Effect of microstructure on the elasto-viscoplastic deformation of dual phase titanium structures

    Ozturk, Tugce; Rollett, Anthony D.


    The present study is devoted to the creation of a process-structure-property database for dual phase titanium alloys, through a synthetic microstructure generation method and a mesh-free fast Fourier transform based micromechanical model that operates on a discretized image of the microstructure. A sensitivity analysis is performed as a precursor to determine the statistically representative volume element size for creating 3D synthetic microstructures based on additively manufactured Ti-6Al-4V characteristics, which are further modified to expand the database for features of interest, e.g., lath thickness. Sets of titanium hardening parameters are extracted from literature, and The relative effect of the chosen microstructural features is quantified through comparisons of average and local field distributions.

  16. Functionalization of titanium surfaces with TGF-beta inhibitor peptides

    Sevilla Sánchez, Pablo


    Esta tesis queda enmarcada en el ámbito de los biomateriales metálicos, concretamente en superficies de titanio desarrolladas para la regeneración ósea. Las aplicaciones más habituales del titanio como biomaterial son los implantes dentales y las prótesis de cadera y rodilla. Estos componentes requieren, en servicio, buena estabilidad y fijación al hueso a largo plazo. El titanio es un material idóneo para el cumplimiento de estos requisitos gracias a su alta resistencia mecánica, tenacidad, ...

  17. Functionalization of titanium surfaces with TGF-beta inhibitor peptides

    Sevilla Sánchez, Pablo


    Premi extraordinari doctorat curs 2012-2013, àmbit d’Enginyeria Industrial Esta tesis queda enmarcada en el ámbito de los biomateriales metálicos, concretamente en superficies de titanio desarrolladas para la regeneración ósea. Las aplicaciones más habituales del titanio como biomaterial son los implantes dentales y las prótesis de cadera y rodilla. Estos componentes requieren, en servicio, buena estabilidad y fijación al hueso a largo plazo. El titanio es un material idóneo para el cumpli...

  18. Titanium in 1980

    Minkler, Ward W.


    Much attention is being focused on the availability and use of non-fuel minerals in the United States. Because of the rapid increase in demand since 1978, titanium has been one of the much-publicized metals in this group. Sponge producers are now expanding sponge manufacturing plants to meet this greater demand, and it now appears that there could be a surplus of sponge in 1981. A delay in airplane purchases caused by severe operating losses of the airlines could have a significant effect on mill product shipments in 1981. However, there is no reason to believe that titanium has reached maturity as a structural aerospace or industrial metal. While it is unreasonable to anticipate that demand will continue to grow at the same rate experienced between 1978 and 1980, new greenfield capacity will nevertheless be required in the early 1980s. Two basic issues must be resolved before such ventures become reality: 1) choice of process; and 2) method for financing, either public or private. Both will be the subject of study and debate in 1981.

  19. Research into Grinding Hardening of Microalloyed Non-quenched and Tempered Steel

    HAN Zheng-tong; ZHANG Ning-ju; GAO Ding; YANG Gang


    Grinding hardening is a new technology of hardening steel piece surfaces with grinding heat generated in the grinding process instead of with a high or medium frequency induction heating method, which can effectively integrate grinding and surface hardening. Experimental studies were carried out on grinding hardening of non-quenched and tempered steel. Through grinding experiments with variable depths of cut and feeding rate, the variation in the depth of the hardening layer was studied and the microstructure of the hardening zone of the test pieces was subsequently analyzed. In the end, the hardening effect of non-quenched and tempered steel was compared with that of 40Cr steel, which revealed the superiority of non-quenched and tempered steel in grinding hardening technology.

  20. Differential hardening in IF steel - Experimental results and a crystal plasticity based model

    Mulder, J.; Eyckens, P.; van den Boogaard, Antonius H.; Hora, P.


    Work hardening in metals is commonly described by isotropic hardening, especially for monotonically increasing proportional loading. The relation between different stress states in this case is determined by equivalent stress and strain definitions, based on equal plastic dissipation. However,

  1. Rapid cold hardening process of insects and its ecologically adaptive significance

    WANG Xianhui; QI Xianlei; KANG Le


    In contrast to overwintering cold hardening, a rapid cold hardening process has recently been described in insects. This process can rapidly enhance cold tolerance of insects in several hours or even minutes. The characteristics of rapid cold hardening include inducing conditions, cold hardening effects, and fitness costs. Physiological and biochemical mechanisms of rapid cold hardening include rapid changes in the phospholipid composition and the increase in hemolymph osmolalities, polyols production, proline and cold-induced proteins. Moreover, there are different views about the ecologically adaptive significance of rapid cold hardening in insects. This paper reviews research results about rapid cold hardening of insects since 1987, focusing on forms of cold injury, strategies of cold tolerance, and definitions, characteristics, physiological and biochemical mechanisms and adaptive significance of rapid cold hardening.

  2. Effect of hardening methods of moulding sands with water glass on structure of bonding bridges

    M. Stachowicz


    Full Text Available Research on influence of hardening methods on structure of bonding bridges in moulding sands with sodium water glass is presented.Moulding sands with addition of 2.5 % of binder with molar module 2.0 were hardened with CO2 and dried in traditional way or hardenedwith microwaves. It was proved that the hardening method affects structure of bonding bridges, correlating with properties of the hardened moulding sands. It was found that strength of the moulding sands hardened with microwaves for 4 min is very close to that measured after traditional drying at 110 °C for 120 min. So, application of microwave hardening ensures significant shortening of the process time to the value comparable with CO2 hardening but guaranteeing over 10-fold increase of mechanical properties. Analysis of SEM images of hardened moulding sands permitted explaining differences in quality parameters of moulding sands by connecting them with structure of the created bonding bridges.

  3. Corroding and Protecting of Surface Residual Stress With the Surface Hardening of Steel

    ZOU Qing-hua


    The states of the stress with the surface hardening are analyzed, the related experiential formula of the stress -temperature and stress-depth hardened curves are set up, the protecting measures against hydrogen stress corrosion are discussed.

  4. Structure of. cap alpha. -phase in two-phase titanium alloys

    Gridnev, V.N.; Ivasishin, O.M.; Svechnikov, V.L. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)


    The structure of ..cap alpha..-phase in ..beta..-annealed titanium alloys VT 6 and VT 23 and its changes on heating up to ..cap alpha..+..beta.. ..-->.. ..beta.. transformation temperatures with accelerated cooling is studied. An assumption is made that the observed peculiarities of the residual ..cap alpha..-phase structure in alloys after such treatment are the consequence of the relaxation of interphase stresses resulting from a partial polymorphic transformation while the relaxation mechanism is determined by the alloying degree and initial alloy morphology.

  5. Analysis of Laser Surface Hardened Layers of Automobile Engine Cylinder Liner

    LIU Xiu-bo; YU Gang; GUO Jian; SHANG Quan-yi; ZHANG Zhen-guo; GU Yi-jie


    Gray cast iron that is used for automobile engine cylinder liners was laser surface hardened using Nd∶YAG quasi-continuous and CO2 continuous wave laser, respectively. The macromorphology and microstructure of the laser surface hardened layers were investigated using an optical microscope. Geometric dimensions including depth and width and microhardness distribution of the hardened layers were also examined in order to evaluate the quality of the hardened layers.

  6. Strain hardening of polymer glasses: Entanglements, energetics, and plasticity

    Hoy, Robert S.; Robbins, Mark O.


    Simulations are used to examine the microscopic origins of strain hardening in polymer glasses. While stress-strain curves for a wide range of temperature can be fit to the functional form predicted by entropic network models, many other results are fundamentally inconsistent with the physical picture underlying these models. Stresses are too large to be entropic and have the wrong trend with temperature. The most dramatic hardening at large strains reflects increases in energy as chains are pulled taut between entanglements rather than a change in entropy. A weak entropic stress is only observed in shape recovery of deformed samples when heated above the glass transition. While short chains do not form an entangled network, they exhibit partial shape recovery, orientation, and strain hardening. Stresses for all chain lengths collapse when plotted against a microscopic measure of chain stretching rather than the macroscopic stretch. The thermal contribution to the stress is directly proportional to the rate of plasticity as measured by breaking and reforming of interchain bonds. These observations suggest that the correct microscopic theory of strain hardening should be based on glassy state physics rather than rubber elasticity.

  7. Hardening digital systems with distributed functionality: robust networks

    Vaskova, Anna; Portela-Garcia, Marta; Garcia-Valderas, Mario; López-Ongil, Celia; Portilla, Jorge; Valverde, Juan; de la Torre, Eduardo; Riesgo, Teresa


    Collaborative hardening and hardware redundancy are nowadays the most interesting solutions in terms of fault tolerance achieved and low extra cost imposed to the project budget. Thanks to the powerful and cheap digital devices that are available in the market, extra processing capabilities can be used for redundant tasks, not only in early data processing (sensed data) but also in routing and interfacing1

  8. Hardening by twin boundary during nanoindentation in nanocrystals.

    Qu, Shaoxing; Zhou, Haofei


    The atomistic deformation processes of nanocrystals embedded with nanoscale twin boundaries during nanoindentation are studied by molecular dynamics simulations. Load-displacement curves are obtained and the hardening mechanisms associated with the nanoscale twin boundaries are revealed. Johnson's theoretical indentation model is adopted to estimate the elastic stage of the nanoindentation. In addition, twin boundary-mediated dislocation nucleation is observed and analyzed.

  9. Preparation of Dispersion-Hardened Copper by Internal Oxidation

    Brøndsted, Povl; Sørensen, Ole Toft


    Internal oxidation experiments in CO2/CO atmospheres on Cu-Al alloys for preparation of dispersion-hardened Cu are described. The oxygen pressures of the atmospheres used in the experiments were controlled with a solid electrolyte oxygen cell based on ZrO2 (CaO). The particle size distributions...

  10. Coefficient of work-hardening in stage-IV

    Nabarro, FRN


    Full Text Available The theory of work hardening in stage IV depends on the relation between the relative misorientation Psi of neighbouring subgrains and the plastic strain gamma (Psi = B gamma exp). The value of the constant B is suggested to be better related...

  11. Decorative application of strain-hardening cementitious composites

    Ibrovic, V.; Lukovic, M.; Schlangen, E.


    Strain hardening cementitious composites (SHCC) have been used in variety of structural applications. Apart from this, they are also suitable for non-structural applications. In this work, the application of SHCC for producing cover plates for light switches and power sockets is presented. For desig

  12. Case Depth Measurement of Induction Hardening Using Image Processing

    Kitti Pongsathaporn; Pramuk Jenkittiyon; Siriporn Daopiset; Somnuk Watanasriyakul


    Case depth measurement of the induction hardened steel parts is necessary for quality control. Vickers microhardness test is the most industrially accepted method to identify the case depth. But this method is a time consuming one and it requires expensive equipment. The aim of this study is to develop a different method to determine the case depth using image processing. The surface hardened steel samples were cross cut, ground and etched with Nital. The etched macrosectioned specimens were scanned by a scanner. The scanned images were evaluated by the developed software. The principle of the software is to identify the gray level difference. The effective case depths of the surface hardened specimens obtained by Vickers microhardness test and the developed method were compared. It was found that the deviation of the developed method was ±0.12 mm at the case depth range of 0.6 - 2.0 mm and ±0.14 mm at the case depth range of 2.1 - 4.3 mm. The measuring time was only 20% of Vickers microhardness test. The deviation range is much lower than the tolerance case depth specification for induction hardening in general.

  13. Decorative application of strain-hardening cementitious composites

    Ibrovic, V.; Lukovic, M.; Schlangen, E.


    Strain hardening cementitious composites (SHCC) have been used in variety of structural applications. Apart from this, they are also suitable for non-structural applications. In this work, the application of SHCC for producing cover plates for light switches and power sockets is presented. For

  14. Purification and utilization of titanium

    Kim, Wonbaek; Yu, Hyosin; Chung, Inwha; Rhee, Kang In; Choi, Good Sun; Lee, Chulkyung; Youn, In Ju; Chung, Jinki; Suh, Chang Youl; Yang, Dong Hyo [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)


    Current domestic market appears not to be sufficient enough for the large scale investment for the expensive vacuum-melting equipment. Besides, related ingot-processing technologies like rolling, extrusion, and forging of titanium should be prepared in advance. In the mean time, the attempt to recycle expensive titanium scraps produced in our nation would be worthwhile in view of the reduction of import from foreign countries and of saving valuable secondary resources. The objectives for this research is to develop technology for the production of high purity titanium metals from sponges and scraps and to extend the developed technology to industrial applications. PREP(Plasma-Rotating-Electrode Process) and HDP(Hydride-Dehydride Process) were adopted to evaluate the possibility of using domestic titanium scraps in the production of pure titanium powders. Those scraps were titanium pipes of Grade 2 and various sputtering targets having a purity of 99.995%. The titanium powders produced by both methods were examined and compared with conventionally prepared ones. Their shape, size distribution, structure and above of all major impurities were determine to evaluate these process. The powders produced by PREP were of round shape having narrow size distribution at about 200 micron. Meanwhile, HDP powders were irregular shaped having a much wider size distribution. Both metallic and non-metallic impurities were lower in PREP powders due to the unavoidable contamination during crushing processes in HDP. Thus, PREP has advantages towards purity and uniformity while HDP toward finer sizes. Apparently, for the production of high purity titanium powders by HDP, special considerations should be made to prevent contamination during various steps in the process. In PREP powders, smaller particles contained more oxygen since they have larger surface/volume ratio. The tendency was also observed in the hardness measurement revealing the strengthening effect of oxygen in pure

  15. Theoretical Studies of Laws Nanostructuring and Heterogeneous Hardening of Steel Samples by Wave Intensive Plastic Deformation

    A.V. Kirichek


    Full Text Available Theoretical studies and calculations, allowing to define the required parameters of the wave deformation hardening, are performed in order to obtain heterogeneous hardened surface layer in steel samples. The conditions for the effective use of impact energy for elastic-plastic deformation of the processed material and the establishment of a deep hardened surface layer are revealed.

  16. Application of Artificial Neural Network to Predicting Hardenability of Gear Steel

    GAO Xiu-hua; QI Ke-min; DENG Tian-yong; QIU Chun-lin; ZHOU Ping; DU Xian-bin


    The prediction of the hardenability and chemical composition of gear steel was studied using artificial neural networks. A software was used to quantitatively forecast the hardenability by its chemical composition or the chemical composition by its hardenability. The prediction result is more precise than that obtained from the traditional method based on the simple mathematical regression model.

  17. The prediction of differential hardening behaviour of steels by multi-scale crystal plasticity modelling

    Eyckens, P.; Mulder, J.; Gawad, J.; Vegter, H.; Roose, D.; Boogaard, van den A.H.; Van Bael, A.; Van Houtte, P.


    An essential aspect of materials modelling in the field of metal plasticity is hardening. The classical assumption of isotropic hardening in metal plasticity models is often too simplified to describe actual material behaviour. This paper focuses on the non-isotropic hardening termed differential ha

  18. Antimicrobial titanium/silver PVD coatings on titanium

    Thull Roger; Glückermann Susanne K; Ewald Andrea; Gbureck Uwe


    Abstract Background Biofilm formation and deep infection of endoprostheses is a recurrent complication in implant surgery. Post-operative infections may be overcome by adjusting antimicrobial properties of the implant surface prior to implantation. In this work we described the development of an antimicrobial titanium/silver hard coating via the physical vapor deposition (PVD) process. Methods Coatings with a thickness of approximately 2 μm were deposited on titanium surfaces by simultaneous ...

  19. Advanced titanium processing

    Hartman, Alan D.; Gerdemann, Stephen J.; Schrems, Karol K.; Holcomb, Gordon R.; Argetsinger, Edward R.; Hansen, Jeffrey S.; Paige, Jack I.; Turner, Paul C.


    The Albany Research Center of the U.S. Department of Energy has been investigating a means to form useful wrought products by direct and continuous casting of titanium bars using cold-wall induction melting rather than current batch practices such as vacuum arc remelting. Continuous ingots produced by cold-wall induction melting, utilizing a bottomless water-cooled copper crucible, without slag (CaF2) additions had minor defects in the surface such as ''hot tears''. Slag additions as low as 0.5 weight percent were used to improve the surface finish. Therefore, a slag melted experimental Ti-6Al-4V alloy ingot was compared to a commercial Ti-6Al-4V alloy ingot in the areas of physical, chemical, mechanical, and corrosion attributes to address the question, ''Are any detrimental effects caused by slag addition''?

  20. Hemocompatibility of titanium nitride.

    Dion, I; Baquey, C; Candelon, B; Monties, J R


    The left ventricular assist device is based on the principle of the Maillard-Wenkel rotative pump. The materials which make up the pump must present particular mechanical, tribological, thermal and chemical properties. Titanium nitride (TiN) because of its surface properties and graphite because of its bulk characteristics have been chosen. The present study evaluated the in vitro hemocompatibility of TiN coating deposited by the chemical vapor deposition process. Protein adsorption, platelet retention and hemolysis tests have been carried out. In spite of some disparities, the TiN behavior towards albumin and fibrinogen is interesting, compared with the one of a reference medical grade elastomer. The platelet retention test gives similar results as those achieved with the same elastomer. The hemolysis percentage is near to zero. TiN shows interesting characteristics, as far as mechanical and tribological problems are concerned, and presents very encouraging blood tolerability properties.

  1. Joining characteristics of titanium-based orthodontic wires connected by laser and electrical welding methods.

    Matsunaga, Junko; Watanabe, Ikuya; Nakao, Noriko; Watanabe, Etsuko; Elshahawy, Waleed; Yoshida, Noriaki


    This study investigated the possibility of electrical and laser welding to connect titanium-based alloy (beta-titanium and nickel-titanium) wires and stainless-steel or cobalt-chromium alloy wires for fabrication of combination arch-wires. Four kinds of straight orthodontic rectangular wires (0.017 × 0.025 inch) were used: stainless-steel (S-S), cobalt-chromium (Co-Cr), beta-titanium alloy (β-Ti), and nickel-titanium (Ni-Ti). Homogeneous and heterogeneous end-to-end joints (15 mm long each) were made by electrical welding and laser welding. Non-welded wires (30 mm long) were also used as a control. Maximum loads at fracture (N) and elongation (%) were measured by conducting tensile test. The data (n = 10) were statistically analyzed using analysis of variance/Tukey test (P welding and those of the S-S/S-S and Co-Cr/Co-Cr specimens welded by laser. On the other hand, the laser-welded Ni-Ti/Ni-Ti and β-Ti/β-Ti specimens exhibited higher values of the ML and EL compared to those of the corresponding specimens welded by electrical method. In the heterogeneously welded combinations, the electrically welded Ni-Ti/S-S, β-Ti/S-S and β-Ti/Co-Cr specimens showed significantly (P welded by laser. Electrical welding exhibited the higher values of maximum load at fracture and elongation for heterogeneously welded combinations than laser-welding.

  2. Accelerated kinetics and mechanism of growth of boride layers on titanium under isothermal and cyclic diffusion

    Sarma, Biplab


    , has been investigated. It was found that thermal cyclic B diffusion in Ti across the alpha(alpha)-beta(beta) phase transition temperature led to highly hardened surface layers enriched with TiB whiskers that grow to depths exceeding 120 mum. By solving the transient heat transport problem for cyclic changes in surface temperatures, it was found that there is a "heat-packet" that travels back and forth from the surface to the interior of the material. This heat-packet appears to transport B dissolved in beta-Ti into interior causing increased coating depths.

  3. Electrochemical process of titanium extraction



    A wide variety of processes are being pursued by researchers for cost effective extraction of titanium metal. Electrochemical processes are promising due to simplicity and being less capital intensive. Some of the promising electrochemical processes of titanium extraction were reviewed and the results of laboratory scale experiments on electrochemical reduction of TiO2 granules were brought out. Some of the kinetic parameters of the reduction process were discussed while presenting the quality improvements achieved in the experimentation.

  4. Low cost titanium--myth or reality

    Turner, Paul C.; Hartman, Alan D.; Hansen, Jeffrey S.; Gerdemann, Stephen J.


    In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of rutile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium, and titanium cost has prevented its use in non-aerospace applications including the automotive and heavy vehicle industries.

  5. Microstructural variation of hardened cement-fly ash pastes leached by soft water


    The microstructural variations of hardened cement-fly ash pastes leached by soft water were investigated by MIP, XRD, TG and SEM. The results show that the mass of hardened cement-fly ash paste reduces and its microstructure deteriorates partly after leaching of soft water. At the leaching duration of 180 days, the hardened paste containing fly ash deteriorated a little more serious than the plain cement paste, but the incorporation of fly ash in a proper ratio was helpful to defer the trend of deterioration of the hardened paste microstructure. The microstructural stability of hardened cement-fly ash paste wasn’t damaged severely during the 180 days leaching duration.

  6. Effect of hardening methods of moulding sands with water glass on structure of bonding bridges

    Stachowicz, M.; K. Granat; Nowak, D.


    Research on influence of hardening methods on structure of bonding bridges in moulding sands with sodium water glass is presented.Moulding sands with addition of 2.5 % of binder with molar module 2.0 were hardened with CO2 and dried in traditional way or hardenedwith microwaves. It was proved that the hardening method affects structure of bonding bridges, correlating with properties of the hardened moulding sands. It was found that strength of the moulding sands hardened with microwaves for 4...

  7. Titanium in the geothermal industry

    Thomas, R. [TIMET UK Ltd., Swansea (United Kingdom)


    Titanium resists seawater and brine at temperatures as high as 260{sup o}C, and is also resistant to corrosion by sulphur dioxide; hydrogen sulphide; and aqueous solutions of those gases. Titanium is fully resistant to corrosion and stress corrosion cracking in the standard NACE test solution containing 3000 ppm dissolved H{sub 2}S, 5% NACl, and 0.5% acetic acid (pH 3.5). To avoid pitting at temperatures above 80{sup o}C, titanium alloys containing nickel, molybdenum, palladium or ruthenium are used. Examples of equipment fabricated in titanium in order to withstand the corrosive fluids present in some geothermal installations are plate heat exchangers and well casing. By careful selection of the grade of titanium, material thickness (with no corrosion allowance) and fabrication method, an economic fabrication with low maintenance costs and high availability can be achieved. A prime example of the application of titanium in the geothermal industry is the use of Grade 29 well casing in the Salton Sea, USA, which enables the exploitation of a geothermal resource containing highly corrosive brine. Advances in production technology are being applied to reduce the cost of the casing pipe. This technology may enable the use of sea water injection to augment weak or depleted aquifers, or to generate steam from Hot Dry Rocks. (author)

  8. Design Features of Hardening Turners with Outstripping Plastic Deformation

    V. M. Yaroslavtsev


    Full Text Available An efficiency of the cutting method with outstripping plastic deformation (OPD in lathe works is defined in many respects by design features of the add-on devices for mechanical hardening of a cut-off layer material in the course of cutting. Applied on lathes, deforming OPD devices can have differing dimensions, placement on the lathe, drive type (manual, electric, hydraulic, pneumatic, pneumohydraulic, electromagnetic, and autonomy degree towards the metalcutting equipment and industrial equipment.At the same time there are a number of inherent design features of work-hardening devices the modernized lathes with OPD use for machining. Now the OPD standard devices implement two principle construction options: loading device is placed on the machine or on the OPD slide support separate of the tool, or it is structurally aligned with the cutting tool. In the latter case the OPD device for turning is called a tool mandrel, which is mounted in a tool post of the machine or, at large dimensions, such a mandrel is mounted on the machine instead of the tool mandrel.When designing the OPD devices, is important to take into consideration production requirements and recommendations for the technological equipment, developed in the course of creation, working off and introduction of such installations for mechanical hardening of material. In compliance with it, OPD devices, their placement on the machine, and working displacements shouldn't limit technological capabilities of the applied metal-cutting equipment. OPD stresses have to be smoothly regulated, with maximum loads being limited to admissible values for the machine model to be modernized. It is necessary to ensure synchronized longitudinal and cross displacements of the cutting tool and OPD hardener with respect to the axis of billet rotation to enable regulation and readjustment of the hardener and tool placement. It ought to foresee the increased mobile components rigidity and manufacturing

  9. Strain Hardening and Size Effect in Five-fold Twinned Ag Nanowires.

    Narayanan, Sankar; Cheng, Guangming; Zeng, Zhi; Zhu, Yong; Zhu, Ting


    Metallic nanowires usually exhibit ultrahigh strength but low tensile ductility owing to their limited strain hardening capability. Here we study the unique strain hardening behavior of the five-fold twinned Ag nanowires by nanomechanical testing and atomistic modeling. In situ tensile tests within a scanning electron microscope revealed strong strain hardening behavior of the five-fold twinned Ag nanowires. Molecular dynamics simulations showed that such strain hardening was critically controlled by twin boundaries and pre-existing defects. Strain hardening was size dependent; thinner nanowires achieved more hardening and higher ductility. The size-dependent strain hardening was found to be caused by the obstruction of surface-nucleated dislocations by twin boundaries. Our work provides mechanistic insights into enhancing the tensile ductility of metallic nanostructures by engineering the internal interfaces and defects.

  10. Grain size effect on yield strength of titanium alloy implanted with aluminum ions

    Popova, Natalya, E-mail: [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk (Russian Federation); Nikonenko, Elena, E-mail: [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); National Research Tomsk Polytechnic University, 30, Lenin Str., 634050, Tomsk (Russian Federation); Yurev, Ivan, E-mail: [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); Kalashnikov, Mark, E-mail: [Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk (Russian Federation); Kurzina, Irina, E-mail: [National Research Tomsk State University, 36, Lenin Str., 634050, Tomsk (Russian Federation)


    The paper presents a transmission electron microscopy (TEM) study of the microstructure and phase state of commercially pure titanium VT1-0 implanted by aluminum ions. This study has been carried out before and after the ion implantation for different grain size, i.e. 0.3 µm (ultra-fine grain condition), 1.5 µm (fine grain condition), and 17 µm (polycrystalline condition). This paper presents details of calculations and analysis of strength components of the yield stress. It is shown that the ion implantation results in a considerable hardening of the entire thickness of the implanted layer in the both grain types. The grain size has, however, a different effect on the yield stress. So, both before and after the ion implantation, the increase of the grain size leads to the decrease of the alloy hardening. Thus, hardening in ultra-fine and fine grain alloys increased by four times, while in polycrystalline alloy it increased by over six times.

  11. A fully associative, nonisothermal, nonlinear kinematic, unified viscoplastic model for titanium alloys

    Arnold, S. M.; Saleeb, A. F.; Castelli, M. G.


    Specific forms for both the Gibb's and complementary dissipation potentials are chosen such that a complete (i.e., fully associative) potential base multiaxial, nonisothermal unified viscoplastic model is obtained. This model possesses one tensorial internal state variable (that is, associated with dislocation substructure) and an evolutionary law that has nonlinear kinematic hardening and both thermal and strain induced recovery mechanisms. A unique aspect of the present model is the inclusion of nonlinear hardening through the use of a compliance operator, derived from the Gibb's potential, in the evolution law for the back stress. This nonlinear tensorial operator is significant in that it allows both the flow and evolutionary laws to be fully associative (and therefore easily integrated), greatly influences the multiaxial response under non-proportional loading paths, and in the case of nonisothermal histories, introduces an instantaneous thermal softening mechanism proportional to the rate of change in temperature. In addition to this nonlinear compliance operator, a new consistent, potential preserving, internal strain unloading criterion has been introduced to prevent abnormalities in the predicted stress-strain curves, which are present with nonlinear hardening formulations, during unloading and reversed loading of the external variables. The specific model proposed is characterized for a representative titanium alloy commonly used as the matrix material in SiC fiber reinforced composites, i.e., TIMETAL 21S. Verification of the proposed model is shown using 'specialized' non-standard isothermal and thermomechanical deformation tests.

  12. Radiation Hardening of LED Luminaires for Accelerator Tunnels

    Devine, James D


    This paper summarises progress made towards the radiation hardening of LED emergency luminaires for evacuation and emergency response within the underground areas of the CERN accelerator complex. The objective has been to radiation harden existing Commercial Off-The-Shelf (COTS) emergency luminaires to maximise lighting performance, without compromising IEC 60598-2-22 compliance. A systems level approach has been adopted, leading to the development of a diode bridge based AC/DC power converter. Modified COTS luminaires including this converter design have been irradiated (to 100 kGy TID using a Cobalt-60 source), with results of a subsequent photometric analysis presented. Following encouraging tests results, a reference design for the power converter has been released under the CERN Open Hardware License to encourage manufacturer adoption. The paper concludes with areas of interest for future research in further improving the radiation hardness of LED emergency lighting for accelerators with detailed studies...

  13. Segmentation-free empirical beam hardening correction for CT

    Schüller, Sören; Sawall, Stefan [German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120 (Germany); Stannigel, Kai; Hülsbusch, Markus; Ulrici, Johannes; Hell, Erich [Sirona Dental Systems GmbH, Fabrikstraße 31, 64625 Bensheim (Germany); Kachelrieß, Marc, E-mail: [German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)


    Purpose: The polychromatic nature of the x-ray beams and their effects on the reconstructed image are often disregarded during standard image reconstruction. This leads to cupping and beam hardening artifacts inside the reconstructed volume. To correct for a general cupping, methods like water precorrection exist. They correct the hardening of the spectrum during the penetration of the measured object only for the major tissue class. In contrast, more complex artifacts like streaks between dense objects need other techniques of correction. If using only the information of one single energy scan, there are two types of corrections. The first one is a physical approach. Thereby, artifacts can be reproduced and corrected within the original reconstruction by using assumptions in a polychromatic forward projector. These assumptions could be the used spectrum, the detector response, the physical attenuation and scatter properties of the intersected materials. A second method is an empirical approach, which does not rely on much prior knowledge. This so-called empirical beam hardening correction (EBHC) and the previously mentioned physical-based technique are both relying on a segmentation of the present tissues inside the patient. The difficulty thereby is that beam hardening by itself, scatter, and other effects, which diminish the image quality also disturb the correct tissue classification and thereby reduce the accuracy of the two known classes of correction techniques. The herein proposed method works similar to the empirical beam hardening correction but does not require a tissue segmentation and therefore shows improvements on image data, which are highly degraded by noise and artifacts. Furthermore, the new algorithm is designed in a way that no additional calibration or parameter fitting is needed. Methods: To overcome the segmentation of tissues, the authors propose a histogram deformation of their primary reconstructed CT image. This step is essential for the

  14. Age-hardening in a commercial Mg-based alloy

    Macchi, C.E. [IFIMAT, UNCentro and CONICET, Pinto 399, B7000GHG Tandil (Argentina); Somoza, A. [IFIMAT, UNCentro and CICPBA, Pinto 399, B7000GHG Tandil (Argentina); Nie, J.F. [School of Physics and Materials Engineering, PO Box 69M, Monash University, Victoria 3800 (Australia)


    Age-hardening phenomena induced by thermal and thermo-mechanical treatments in the commercial Mg-based alloy WE54 were studied by positron annihilation lifetime spectroscopy and Vickers microhardness. To this aim, samples were plastically deformed and subsequently aged at 250 C for times ranging from 0 to 1000 hours. The results obtained are discussed in terms of the role of vacancies in the solute transport and therefore they contribute to the discussion on the vacancy-solute clusters (and/or intermediate precipitates) interactions during the precipitation sequence of the WE54. Besides, we show that cold work previous aging not only accelerates but increases the hardening response of the alloy. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Hardening electronic devices against very high total dose radiation environments

    Buchanan, B.; Shedd, W.; Roosild, S.; Dolan, R.


    The possibilities and limitations of hardening silicon semiconductor devices to the high neutron and gamma radiation levels and greater than 10 to the eighth power rads required for the NERVA nuclear engine development are discussed. A comparison is made of the high dose neutron and gamma hardening potential of bipolar, metal insulator semiconductors and junction field effect transistors. Experimental data is presented on device degradation for the high neutron and gamma doses. Previous data and comparisons indicate that the JFET is much more immune to the combined neutron displacement and gamma ionizing effects than other transistor types. Experimental evidence is also presented which indicates that p channel MOS devices may be able to meet the requirements.

  16. Poromechanical behaviour of hardened cement paste under isotropic loading

    Ghabezloo, Siavash; Guédon, Sylvine; Martineau, Francçois; Saint-Marc, Jérémie


    The poromechanical behaviour of hardened cement paste under isotropic loading is studied on the basis of an experimental testing program of drained, undrained and unjacketed compression tests. The macroscopic behaviour of the material is described in the framework of the mechanics of porous media. The poroelastic parameters of the material are determined and the effect of stress and pore pressure on them is evaluated. Appropriate effective stress laws which control the evolution of total volume, pore volume, solid volume, porosity and drained bulk modulus are discussed. A phenomenon of degradation of elastic properties is observed in the test results. The microscopic observations showed that this degradation is caused by the microcracking of the material under isotropic loading. The good compatibility and the consistency of the obtained poromechanical parameters demonstrate that the behaviour of the hardened cement paste can be indeed described within the framework of the theory of porous media.

  17. Laser surface hardening of AISI H13 tool steel

    Jae-Ho LEE; Jeong-Hwan JANG; Byeong-Don JOO; Young-Myung SON; Young-Hoon MOON


    An attempt was made to improve the surface hardness and wear properties of AISI H13 tool steel through solid solution hardening and refinement of microstructures using a 200 W fiber laser as a heat generating source. The hardness of laser melted zone was investigated. In order to identify the effect of heat input on the laser melting zone, scanning conditions were controlled. The results show that, the hardness of as-received AISI H13 tool steel is approximately Hv 240, and the hardness after laser surface heat treatment is around Hv 480-510. The hardening depth and width are increased with the increase in the heat input applied. Application of experimental results will be considered in tooling industry.


    HUYing-ning; WANGCheng-yong; WUXue-qi; QINZhe; ZENGBao-ping


    Tool wear and breakage of the micro-milling tool is an important problem for high speed machining of hardened steel die and mould. Dry milling of S136 hardened steel is carried out using TiA1N coated carbide micro-end mill (Ф2 mm). The effect of cutting speed, feed per tooth and radial depth of cut on cutting force is analyzed. Cutting parameters adapting to dry machining and strategy optimized for higher rate of material removal with lower cutting force are attained. Results of SEM observation show that the main failure patterns of micro-end mill are breakage of tool tip, wear and drop-off of surface coating, micro-chipping, and breakage of flank.

  19. Beta Thalassemia (For Parents)

    ... Kids to Be Smart About Social Media Beta Thalassemia KidsHealth > For Parents > Beta Thalassemia Print A A ... Complications Symptoms Diagnosis Treatment en español Beta talasemia Thalassemias Thalassemias are a group of blood disorders that ...

  20. Control technology for surface treatment of materials using induction hardening

    Kelley, J.B.; Skocypec, R.D. [Sandia National Labs., NM (United States)


    In the industrial and automotive industries, induction case hardening is widely used to provide enhanced strength, wear resistance, and toughness in components made from medium and high carbon steels. The process uses significantly less energy than competing batch process, is environmentally benign, and is a very flexible in-line manufacturing process. As such, it can directly contribute to improved component reliability, and the manufacture of high-performance lightweight parts. However, induction hardening is not as widely used as it could be. Input material and unexplained process variations produce significant variation in product case depth and quality. This necessitates frequent inspection of product quality by destructive examination, creates higher than desired scrap rates, and causes de-rating of load stress sensitive components. In addition, process and tooling development are experience-based activities, accomplished by trial and error. This inhibits the use of induction hardening for new applications, and the resultant increase in energy efficiency in the industrial sectors. In FY96, a Cooperative Research and Development Agreement under the auspices of the Technology Transfer Initiative and the Partnership for a New Generation of Vehicles was completed. A multidisciplinary team from Sandia National Labs and Delphi Saginaw Steering Systems investigated the induction hardening by conducting research in the areas of process characterization, computational modeling, materials characterization, and high speed data acquisition and controller development. The goal was to demonstrate the feasibility of closed-loop control for a specific material, geometry, and process. Delphi Steering estimated annual savings of $2-3 million per year due to reduced scrap losses, inspection costs, and machine down time if reliable closed-loop control could be achieved. A factor of five improvement in process precision was demonstrated and is now operational on the factory floor.

  1. Optimizing hardenability of high chromium white cast iron

    SU Ying-long; LI Dan; ZHANG Xue-kun


    The formulas proposed by J. Dodd and J. L. Parks for calculating the hardenability of high-Cr white cast iron under continuous cooling condition was recommended. For broader application, some supplements were made to the formula. Through tests on the half-cooling time of typical castings, the compositions of ideal alloys were precisely designed using the Dodd's formula. Hardness testing of heat-treated castings showed that the designed compositions were correct. The application of castings demonstrated excellent abrasion resistance.

  2. Sequential circuit design for radiation hardened multiple voltage integrated circuits

    Clark, Lawrence T.; McIver, III, John K.


    The present invention includes a radiation hardened sequential circuit, such as a bistable circuit, flip-flop or other suitable design that presents substantial immunity to ionizing radiation while simultaneously maintaining a low operating voltage. In one embodiment, the circuit includes a plurality of logic elements that operate on relatively low voltage, and a master and slave latches each having storage elements that operate on a relatively high voltage.

  3. Elastic constant versus temperature behavior of three hardened maraging steels

    Ledbetter, H. M.; Austin, M. W.


    Elastic constants of three maraging steels were determined by measuring ultrasonic velocities. Annealed steels show slightly lower bulk moduli and considerably lower shear moduli than hardened steels. All the elastic constants (Young's modulus, shear modulus, bulk modulus and Poisson's ratio) show regular temperature behavior between 76 and 400 K. Young's modulus and the shear modulus increase with increasing yield strength, but the bulk modulus and Poisson's ratio are relatively unchanged. Elastic anisotropy is quite small.

  4. The radiation damage of crystalline silicon PN diode in tritium beta-voltaic battery.

    Lei, Yisong; Yang, Yuqing; Liu, Yebing; Li, Hao; Wang, Guanquan; Hu, Rui; Xiong, Xiaoling; Luo, Shunzhong


    A tritium beta-voltaic battery using a crystalline silicon convertor composed of (100)Si/SiO2/Si3N4 film degrades remarkably with radiation from a high intensity titanium tritide film. Simulation and experiments were carried out to investigate the main factor causing the degradation. The radiation damages mainly comes from the x-ray emitted from the titanium tritide film and beta particle can relieve the damages. The x-ray radiation induced positive charges in the SiO2 film destroying the output property of the PN diode with the induction of an electric field.

  5. Cell response of anodized nanotubes on titanium and titanium alloys.

    Minagar, Sepideh; Wang, James; Berndt, Christopher C; Ivanova, Elena P; Wen, Cuie


    Titanium and titanium alloy implants that have been demonstrated to be more biocompatible than other metallic implant materials, such as Co-Cr alloys and stainless steels, must also be accepted by bone cells, bonding with and growing on them to prevent loosening. Highly ordered nanoporous arrays of titanium dioxide that form on titanium surface by anodic oxidation are receiving increasing research interest due to their effectiveness in promoting osseointegration. The response of bone cells to implant materials depends on the topography, physicochemistry, mechanics, and electronics of the implant surface and this influences cell behavior, such as adhesion, proliferation, shape, migration, survival, and differentiation; for example the existing anions on the surface of a titanium implant make it negative and this affects the interaction with negative fibronectin (FN). Although optimal nanosize of reproducible titania nanotubes has not been reported due to different protocols used in studies, cell response was more sensitive to titania nanotubes with nanometer diameter and interspace. By annealing, amorphous TiO2 nanotubes change to a crystalline form and become more hydrophilic, resulting in an encouraging effect on cell behavior. The crystalline size and thickness of the bone-like apatite that forms on the titania nanotubes after implantation are also affected by the diameter and shape. This review describes how changes in nanotube morphologies, such as the tube diameter, the thickness of the nanotube layer, and the crystalline structure, influence the response of cells.

  6. Microstructure and properties of hot roll bonding layer of dissimilar metals. 1. Effect of oxide layer on titanium surface on bonding strength of titanium clad steel by hot roll bonding; Ishu kinzoku no atsuen setsugo kaimen soshiki to shotokusei ni kansuru kenkyu. 1. Atsuen chitan clad ko no kaimen kyodo ni oyobosu chitan hyomen sankabutsuso no eikyo

    Ogawa, K.; Komizo, Y.; Yasuyama, M. [Sumitomo Metal Industries, Ltd., Osaka (Japan); Ikezaki, H.; Murayama, J.


    The effect of surface oxide layer on the titanium before bonding on the bonding strength of titanium clad steel by hot roll bonding was investigated from a view point of microstructure of the bonding interface. The bonding test of iron and titanium by hot roll bonding at 850{degree}C was conducted under the various surface conditions of titanium plate such as as-relieved, oxidized or machined. The mechanical properties of clad steel was evaluated in terms of tensile test in the rectangular direction to the bonding interface and observation of micro structures of bonding layer. As results, the bonding strength deteriorated remarkably in the clad steel produced using the titanium having oxide layer on the surface comparing with that using the machined surface of titanium. In the clad steel produced using the titanium with surface oxide, uncontinuous intermetallic compound was observed at the interface of {beta}-Ti and Fe, while in the clad steel produced by the titanium without surface oxide, no remarkable intermetallic compound was observed. Oxide layer on the titanium surface promotes the formation of inter metallic compound of titanium and iron at the bonding interface and deterioration of bonding strength. Such oxide layer, however, was found to be not an obstacle to the accomplishment of metallurgical bonding. 6 refs., 13 figs.

  7. Titanium nanostructures for biomedical applications

    Kulkarni, M.; Mazare, A.; Gongadze, E.; Perutkova, Š.; Kralj-Iglič, V.; Milošev, I.; Schmuki, P.; Iglič, A.; Mozetič, M.


    Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications and accounts for their extensive use as implant materials in the last 50 years. Currently, a large amount of research is being carried out in order to determine the optimal surface topography for use in bioapplications, and thus the emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase osteoblast adhesion, maturation and subsequent bone formation. Furthermore, the adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium; namely topography, charge distribution and chemistry. The present review article focuses on the specific nanotopography of titanium, i.e. titanium dioxide (TiO2) nanotubes, using a simple electrochemical anodisation method of the metallic substrate and other processes such as the hydrothermal or sol-gel template. One key advantage of using TiO2 nanotubes in cell interactions is based on the fact that TiO2 nanotube morphology is correlated with cell adhesion, spreading, growth and differentiation of mesenchymal stem cells, which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) tubes, leading to cell death and apoptosis. Research has supported the significance of nanotopography (TiO2 nanotube diameter) in cell adhesion and cell growth, and suggests that the mechanics of focal adhesion formation are similar among different cell types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties.

  8. Precipitation hardening of biodegradable Fe-Mn-Pd alloys

    Moszner, F. [Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich (Switzerland); Sologubenko, A.S. [Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich (Switzerland); Laboratory for Nanometallurgy, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich (Switzerland); Schinhammer, M. [Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich (Switzerland); Lerchbacher, C. [Christian Doppler Laboratory for Early Stages of Precipitation, University of Leoben, Franz-Josef-Strasse 18, 8700 Leoben (Austria); Haenzi, A.C. [Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich (Switzerland); Leitner, H. [Christian Doppler Laboratory for Early Stages of Precipitation, University of Leoben, Franz-Josef-Strasse 18, 8700 Leoben (Austria); Uggowitzer, P.J. [Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich (Switzerland); Loeffler, J.F., E-mail: [Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich (Switzerland)


    This work presents a phenomenological description of the precipitation controlled hardening of a new biodegradable Fe-based alloy developed to fulfill the requirements of temporary implant applications. Pronounced strengthening of the solution-treated martensitic Fe-10Mn-1Pd (in wt.%) alloy upon isothermal aging at temperatures within the ferrite-austenite phase field is observed and attributed to the thermally activated formation of coherent plate-like Pd-rich precipitates on {l_brace}1 0 0{r_brace} planes of the matrix. The onset and the early stages of alloy decomposition were studied using two complementary techniques: transmission electron microscopy and three-dimensional atom probe analysis. Three distinct regions of the hardening kinetics are recognized and closely correlated to the evolution of the alloy microstructure. Upon aging, clustering of Pd atoms within the Fe-Mn solid solution occurs. The very small clusters grow, coarsen and adopt a plate-like shape, rearranging mutually to reduce the overall elastic strain energy. The elastic interaction of the dislocation substructure with Pd-rich precipitates of evolving morphology affects the dislocation mobility and is responsible for the hardness evolution of the alloy. A study of the hardening kinetics shows that the process exhibits all the features characteristic of maraging steels.

  9. Residual stress analysis of drive shafts after induction hardening

    Lemos, Guilherme Vieira Braga; Rocha, Alexandre da Silva; Nunes, Rafael Menezes, E-mail: [Universidade Federal do Rio Grande do Sul (UFRS), Porto Algre, RS (Brazil); Hirsch, Thomas Karl [Stiftung Institut für Werkstofftechnik (IWT), Bremen (Germany)


    Typically, for automotive shafts, shape distortion manifests itself in most cases after the induction hardening by an effect known as bending. The distortion results in a boost of costs, especially due to machining parts in the hardened state to fabricate its final tolerances. In the present study, residual stress measurements were carried out on automotive drive shafts made of DIN 38B3 steel. The samples were selected in consequence of their different distortion properties by an industrial manufacturing line. One tested shaft was straightened, because of the considerable dimensional variation and the other one not. Firstly, the residual stress measurements were carried out by using a portable diffractometer, in order to avoid cutting the shafts and evaluate the original state of the stresses, and afterwards a more detailed analysis was realized by a conventional stationary diffractometer. The obtained results presented an overview of the surface residual stress profiles after induction hardening and displayed the influence of the straightening process on the redistribution of residual stresses. They also indicated that the effects of the straightening in the residual stresses cannot be neglected. (author)

  10. Use of rapidly hardening hydroxyapatite cement for facial contouring surgery.

    Lee, Dong Won; Kim, Ji Ye; Lew, Dae Hyun


    Hydroxyapatite cement is an ideal alloplastic material to replace the autogenous bone grafts in craniofacial surgery. Hydroxyapatite cement is advantageous because it can be easily molded by hand unlike other alloplastic materials such as silicone and high-density polyethylene. For aesthetic applications of hydroxyapatite cement, we evaluated the efficacy and safety of the rapidly hardening hydroxyapatite cement used in facial contour augmentation, especially for the forehead and the malar area. A total of 18 cases of facial skeleton augmentation or contouring surgery using rapidly hardening hydroxyapatite cement (Mimix; Biomet, Warsaw, IN) were examined, and the long-term cosmetic results and any complications were also analyzed. The aims of facial contouring surgeries were to correct the following conditions: hemifacial microsomia, craniosynostosis, posttraumatic facial deformity, deformity after tumor resection, dentofacial deformity, and Romberg disease. The application sites of hydroxyapatite cement were the forehead, malar area, chin, and paranasal area. A mean of 16 g (range, 5-50 g) of the hydroxyapatite cement was used. Postoperative infection, seroma, and migration of the implant were not observed during the follow-up period of 23 months. Rapidly hardening hydroxyapatite cement, Mimix, is easy to manipulate, promptly sclerotized, and can be replaced by living bone tissue, with a low complication rate. Therefore, it can be an optimal treatment that can be used instead of other conventional types of alloplastic materials used in facial contouring surgery.

  11. Study on the hardening mechanism of cement asphalt binder


    The hydration and hardening mechanism of cement asphalt binder(CAB) was studied.The early hydration process,hydration products and paste microstructure of CAB made by Portland cement and anionic asphalt emulsion were investigated by calorimetry,X-ray diffraction,and environmental scanning electron microscopy.The early hydration process of CAB can be characterized as 5 stages similar to those of Portland cement.There is no chemical reaction detected between cement and asphalt,hence no new hydration products other than those of Portland cement are produced.The hardening of CAB begins with the hydration of cement.When the hydration of cement comes into the acceleration period and its exothermic rate comes to the maximum,the coalescence of asphalt particles in asphalt emulsion is triggered.In the hardened system of CAB,it was found that the hydration products of cement form the skeleton and are covered by the continuous asphalt film.They formed an interpenetrating network system.The emulsifiers in the asphalt emulsion may retard the hydration process of cement.

  12. Free Vibration and Hardening Behavior of Truss Core Sandwich Beam

    J. E. Chen


    Full Text Available The dynamic characteristics of simply supported pyramidal truss core sandwich beam are investigated. The nonlinear governing equation of motion for the beam is obtained by using a Zig-Zag theory. The averaged equations of the beam with primary, subharmonic, and superharmonic resonances are derived by using the method of multiple scales and then the corresponding frequency response equations are obtained. The influences of strut radius and core height on the linear natural frequencies and hardening behaviors of the beam are studied. It is illustrated that the first-order natural frequency decreases continuously and the second-order and third-order natural frequencies initially increase and then decrease with the increase of strut radius, and the first three natural frequencies all increase with the rise of the core height. Furthermore, the results indicate that the hardening behaviors of the beam become weaker with the increase of the rise of strut radius and core height. The mechanisms of variations in hardening behavior of the sandwich beam with the three types of resonances are detailed and discussed.

  13. Press Hardening Steel (PHS): a new coating and process technology

    Faderl, J. [voestalpine Stahl Linz GmbH (Austria); Vehof, R. [Polynorm N.V., Bundschoten (Netherlands)


    Press hardening technology has been known for many years. Increased requirements with respect to safety and light weight construction of the steel body for cars and trucks force the automotive industry to use high strength steels more and more. Strength levels up to 1000 MPa can be provided with AHSS grades. Above 1000 MPa, these steel grades are coming to their limit with respect to strength vs. formability balance. PHS is a very attractive alternative concept. Hardenable 22MnB5 has been supplied - uncoated - for a long time. To avoid decarburization during heat treatment and to improve corrosion behaviour hot dip aluminized 22MnB5 was introduced to the market. Both materials, uncoated and hot dip aluminized, do not provide cathodic corrosion protection without postcoating (sheradizing..). In the last two years an improved press hardening technology and a zinc based coating providing cathodic protection was developed by voestalpine. Some results about strength homogeneity, formability, corrosion behaviour of this voestalpine-PHS technology will be presented in the paper. (orig.)

  14. Recent developments in turning hardened steels - A review

    Sivaraman, V.; Prakash, S.


    Hard materials ranging from HRC 45 - 68 such as hardened AISI H13, AISI 4340, AISI 52100, D2 STL, D3 STEEL Steel etc., need super hard tool materials to machine. Turning of these hard materials is termed as hard turning. Hard turning makes possible direct machining of the hard materials and also eliminates the lubricant requirement and thus favoring dry machining. Hard turning is a finish turning process and hence conventional grinding is not required. Development of the new advanced super hard tool materials such as ceramic inserts, Cubic Boron Nitride, Polycrystalline Cubic Boron Nitride etc. enabled the turning of these materials. PVD and CVD methods of coating have made easier the production of single and multi layered coated tool inserts. Coatings of TiN, TiAlN, TiC, Al2O3, AlCrN over cemented carbide inserts has lead to the machining of difficult to machine materials. Advancement in the process of hard machining paved way for better surface finish, long tool life, reduced tool wear, cutting force and cutting temperatures. Micro and Nano coated carbide inserts, nanocomposite coated PCBN inserts, micro and nano CBN coated carbide inserts and similar developments have made machining of hardened steels much easier and economical. In this paper, broad literature review on turning of hardened steels including optimizing process parameters, cooling requirements, different tool materials etc., are done.

  15. Plasma quench production of titanium from titanium tetrachloride

    Sears, J.W.


    This project, Plasma Quench Production of Titanium from Titanium Tetrachloride, centers on developing a technique for rapidly quenching the high temperature metal species and preventing back reactions with the halide. The quenching technique chosen uses the temperature drop produced in a converging/diverging supersonic nozzle. The rapid quench provided by this nozzle prevents the back reaction of the halide and metal. The nature of the process produces nanosized particles (10 to 100 nm). The powders are collected by cyclone separators, the hydrogen flared, and the acid scrubbed. Aluminum and titanium powders have been produced in the laboratory-scale device at 1 gram per hour. Efforts to date to scale up this process have not been successful.

  16. Plasmonic titanium nitride nanostructures for perfect absorbers

    Guler, Urcan; Li, Wen-Wei; Kinsey, Nathaniel


    We propose a metamaterial based perfect absorber in the visible region, and investigate the performance of titanium nitride as an alternative plasmonic material. Numerical and experimental results reveal that titanium nitride performs better than gold as a plasmonic absorbing material...

  17. Intermetallic and titanium matrix composite materials for hypersonic applications

    Berton, B.; Surdon, G.; Colin, C. [Dassault Aviation, Saint-Cloud (France)]|[Aersopatiale Space & Defence, St Medard en Jalles (France)


    As part of the French Program of Research and Technology for Advanced Hypersonic Propulsion (PREPHA) which was launched in 1992 between Aerospatiale, Dassault Aviation, ONERA, SNECMA and SEP, an important work is specially devoted to the development of titanium and intermetallic composite materials for large airframe structures. At Dassault Aviation, starting from a long experience in Superplastic Forming - Diffusion Bonding (SPF-DB) of titanium parts, the effort is brought on the manufacturing and characterization of composites made from Timet beta 21S or IMI 834 foils and Textron SCS6 fiber fabrics. At `Aersopatiale Espace & Defence`, associated since a long time about intermetallic composite materials with university research laboratories, the principal effort is brought on plasma technology to develop the gamma titanium aluminide TiAl matrix composite reinforced by protected silicon carbide fibers (BP SM 1240 or TEXTRON SCS6). The objective, is to achieve, after 3 years of time, to elaborate a medium size integrally stiffened panel (300 x 600 sq mm).

  18. An Evaluation of the Corrosion and Mechanical Performance of Interstitially Surface-Hardened Stainless Steel

    Jones, Jennifer L.; Koul, Michelle G.; Schubbe, Joel J.


    A surface hardening technique called "interstitial hardening" is commercially available, whereby interstitial carbon atoms are introduced into stainless steel surfaces without the formation of carbides. Surface hardening of machine elements such as impellors or fasteners would improve performance regarding cavitation and galling resistance, and has intensified interest in this process. However, there remains a need to characterize and validate the specific performance characteristics of the hardened materials. This paper describes experimental testing conducted on 316L stainless steel that has been surface hardened using available commercial techniques, using carbon as the interstitial atom. The corrosion performance of the hardened surface is assessed using electrochemical potentiodynamic testing to determine the breakdown potential in 3.5 wt.% NaCl solution to identify the most promising method. The hardness and thickness of the surface-hardened layer is characterized and compared using metallography and microhardness profiling. Corrosion fatigue and slow strain rate testing of untreated, hardened, and damaged, hardened surfaces exposed to ASTM seawater is conducted. Finally, critical galling stresses are determined and compared. Post-test examination of damage attempts to identify mechanisms of material failure and characterize how corrosion-assisted cracks initiate and grow in surface-hardened materials.

  19. Lightweight Protective Coatings For Titanium Alloys

    Wiedemann, Karl E.; Taylor, Patrick J.; Clark, Ronald K.


    Lightweight coating developed to protect titanium and titanium aluminide alloys and titanium-matrix composite materials from attack by environment when used at high temperatures. Applied by sol-gel methods, and thickness less than 5 micrometers. Reaction-barrier and self-healing diffusion-barrier layers combine to protect titanium alloy against chemical attack by oxygen and nitrogen at high temperatures with very promising results. Can be extended to protection of other environmentally sensitive materials.

  20. Anodic growth of titanium dioxide nanostructures


    Disclosed is a method of producing nanostructures of titanium dioxide (TiO 2 ) by anodisation of titanium (Ti) in an electrochemical cell, comprising the steps of: immersing a non-conducting substrate coated with a layer of titanium, defined as the anode, in an electrolyte solution...... an electrical contact to the layer of titanium on the anode, where the electrical contact is made in the electrolyte solution...

  1. Laser shock peening of Ti-17 titanium alloy: Influence of process parameters

    Cellard, C.; Retraint, D.; Francois, M. [University of Technology of Troyes (UTT), Charles Delaunay Institute, LASMIS, UMR CNRS 6279, 12 Rue Marie Curie, BP2060, 10010 Troyes Cedex (France); Rouhaud, E., E-mail: [University of Technology of Troyes (UTT), Charles Delaunay Institute, LASMIS, UMR CNRS 6279, 12 Rue Marie Curie, BP2060, 10010 Troyes Cedex (France); Le Saunier, D. [SNECMA Evry - Corbeil, Route Henry Auguste Desbrueres, 91003 Evry (France)


    Highlights: Black-Right-Pointing-Pointer Laser shock peening parameters studied through a design of experiments. Black-Right-Pointing-Pointer Laser fluence, pulse duration, number of impacts and sample thickness are studied. Black-Right-Pointing-Pointer The observed work hardening is low, the roughness is lightly affected. Black-Right-Pointing-Pointer A significant part of hardness increase is due to compressive residual stresses. Black-Right-Pointing-Pointer High tensile residual stresses can appear on thin laser shocked specimens. - Abstract: The influence of the process parameters of laser shock peening was investigated on specimens made of an aeronautic titanium alloy: Ti-5Al-2Sn-2Zr-4Cr-4Mo (Ti-17). In order to quantify the effect of relevant process parameters, an experimental design was carried out. It is based on a full factorial design with four factors (laser fluence, pulse duration, number of impacts and thickness of the sample) and two levels for each factor. The process is characterised with the following variables: the depth of the impacts, the roughness of the treated surface, the hardening of the material (itself evaluated with the hardness and X-ray diffraction peak width), the residual stresses left in the sample and the global curvature of the sample. It is found that all the parameters have an influence on the residual stresses and that laser shock peening has no influence on roughness and low influence on work-hardening. The variables are then analysed in order to evaluate correlations. The increase in hardness is found to be essentially due to compressive residual stresses, cold work-hardening having only a small effect. In thin specimens, the stress redistribution due to self-equilibrium leads to tensile residual stresses at the treated surface and to large deformations of the specimens.

  2. 21 CFR 73.575 - Titanium dioxide.


    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.575 Section 73.575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.575 Titanium dioxide. (a) Identity. (1) The color additive titanium dioxide is synthetically prepared TiO2, free from admixture with other substances. (2)...

  3. 21 CFR 73.2575 - Titanium dioxide.


    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  4. 21 CFR 73.1575 - Titanium dioxide.


    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  5. 40 CFR 180.1195 - Titanium dioxide.


    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide is exempted from the requirement of a tolerance for residues in or...

  6. 21 CFR 73.3126 - Titanium dioxide.


    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891,...

  7. Photonuclear reactions on titanium isotopes

    Belyshev, S. S. [Moscow State University (Russian Federation); Dzhilavyan, L. Z. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Ishkhanov, B. S.; Kapitonov, I. M. [Moscow State University (Russian Federation); Kuznetsov, A. A., E-mail:; Orlin, V. N.; Stopani, K. A. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)


    The photodisintegration of titanium isotopes in the giant-dipole-resonance energy region is studied by the photon-activation method. Bremsstrahlung photons whose spectrum has the endpoint energy of 55 MeV is used. The yields and integrated cross sections are determined for photoproton reactions on the titanium isotopes {sup 47,48,49,50}Ti. The respective experimental results are compared with their counterparts calculated on the basis of the TALYS code and a combined photonucleon-reaction model. The TALYS code disregards the isospin structure of the giant dipole resonance and is therefore unable to describe the yield of photoproton reactions on the heavy titanium isotopes {sup 49,50}Ti.

  8. Adaptive mesh refinement in titanium

    Colella, Phillip; Wen, Tong


    In this paper, we evaluate Titanium's usability as a high-level parallel programming language through a case study, where we implement a subset of Chombo's functionality in Titanium. Chombo is a software package applying the Adaptive Mesh Refinement methodology to numerical Partial Differential Equations at the production level. In Chombo, the library approach is used to parallel programming (C++ and Fortran, with MPI), whereas Titanium is a Java dialect designed for high-performance scientific computing. The performance of our implementation is studied and compared with that of Chombo in solving Poisson's equation based on two grid configurations from a real application. Also provided are the counts of lines of code from both sides.

  9. Crystallographic features of {alpha}``-martensite in titanium alloys

    Ivasishin, O.M. [AN Ukrainskoj SSR, Kiev (Ukraine). Inst. Metallov Fiziki; Kosenko, N.S. [AN Ukrainskoj SSR, Kiev (Ukraine). Inst. Metallov Fiziki; Shevchenko, S.V. [AN Ukrainskoj SSR, Kiev (Ukraine). Inst. Metallov Fiziki


    Equilibrium volume fractions of twins ({alpha}{sub 0}) and habit plane orientation (anti n{sub 0}) of the orthorhombic {alpha}``-martensite in titanium alloys with {beta}-stabilizing elements were determined by minimization of the elastic strain energy. Calculations were made in the basis of one of the twinned domains. It was shown that these parameters are varying considerably depending on the solute element content. For Ti-Ta and Ti-Mo systems habit plane rotated from {l_brace}434{r_brace}{sub {beta}} to {l_brace}433{r_brace}{sub {beta}} pole and {alpha}{sub 0} grew with Ta (Mo) content increase. For Ti-20at%Ta {alpha}{sub 0} reached the value of 1, i.e. martensite plate became monodomain. For Ti-Mo system monodomain state was not achieved. For Ti-Nb system converse concentrational dependence of martensite parameters was obtained: {alpha}{sub 0} decreased with Nb content increase, and n showed a rotation from {l_brace}434{r_brace}{sub {beta}} pole in a direction opposite to that for Ti-Ta and Ti-Mo systems. (orig.).

  10. Experimental Equipment and Basic Technological Methods of Obtaining Cavitation Protective Coatings on Working Surfaces of Steam Turbine Blades Made of Titanium Alloy VT6 in Order to Replace Imports of Similar Products

    Bilous, V.A.


    Full Text Available The experimental equipment and basic technological methods of obtaining сavitation protective coatings on the working surfaces of blades of steam turbines from titanium alloy VT6 have been created. The selection and the basis of the composition and conditions of synthesis of optimal coating for hardening blades have been justified. The parameters of deposition process of coatings on the blade model have been worked, the experimental technological deposition process of hardening coatings has been created. The tests of titanium alloy VT6 samples with the preferred coatings in simulation conditions close to operational have been conducted. The coatings on the blade model of length up to 130 cm and weight up to 30 kg have been deposited. The velocity of the TiN coating depositing was 10 mkm/h.

  11. Effect of whitening toothpaste on titanium and titanium alloy surfaces.

    Faria, Adriana Cláudia Lapria; Bordin, Angelo Rafael de Vito; Pedrazzi, Vinícius; Rodrigues, Renata Cristina Silveira; Ribeiro, Ricardo Faria


    Dental implants have increased the use of titanium and titanium alloys in prosthetic applications. Whitening toothpastes with peroxides are available for patients with high aesthetic requirements, but the effect of whitening toothpastes on titanium surfaces is not yet known, although titanium is prone to fluoride ion attack. Thus, the aim of the present study was to compare Ti-5Ta alloy to cp Ti after toothbrushing with whitening and conventional toothpastes. Ti-5Ta (%wt) alloy was melted in an arc melting furnace and compared with cp Ti. Disks and toothbrush heads were embedded in PVC rings to be mounted onto a toothbrushing test apparatus. A total of 260,000 cycles were carried out at 250 cycles/minute under a load of 5 N on samples immersed in toothpaste slurries. Surface roughness and Vickers microhardness were evaluated before and after toothbrushing. One sample of each material/toothpaste was analyzed by Scanning Electron Microscopy (SEM) and compared with a sample that had not been submitted to toothbrushing. Surface roughness increased significantly after toothbrushing, but no differences were noted after toothbrushing with different toothpastes. Toothbrushing did not significantly affect sample microhardness. The results suggest that toothpastes that contain and those that do not contain peroxides in their composition have different effects on cp Ti and Ti-5Ta surfaces. Although no significant difference was noted in the microhardness and roughness of the surfaces brushed with different toothpastes, both toothpastes increased roughness after toothbrushing.

  12. Improved impact toughness of 13Cr martensitic stainless steel hardened by laser

    Tsay, L. W.; Chang, Y. M.; Torng, S.; Wu, H. C.


    The impact toughness of AISI 403 martensitic stainless steel plate and laser-hardened specimens tempered at various temperatures were examined. Phosphorus was the primary residual impurity responsible for tempered embrittlement of this alloy. The experimental result also indicated that AISI 403 stainless steel was very sensitive to reverse-temper embrittlement. The improved impact toughness of the laser-hardened specimen was attributed to the refined microstructure in the laser-hardened zone.

  13. Development of a Pressure-Dependent Constitutive Model with Combined Multilinear Kinematic and Isotropic Hardening

    Allen Phillip A.; Wilson, Christopher D.


    The development of a pressure-dependent constitutive model with combined multilinear kinematic and isotropic hardening is presented. The constitutive model is developed using the ABAQUS user material subroutine (UMAT). First the pressure-dependent plasticity model is derived. Following this, the combined bilinear and combined multilinear hardening equations are developed for von Mises plasticity theory. The hardening rule equations are then modified to include pressure dependency. The method for implementing the new constitutive model into ABAQUS is given.

  14. The hardening compositions from the burnt rocks for using in the mining conditions

    Galpern, E.I. [Inst. of Industrial Construction and Building, Donetsk, (Ukraine); Pashchenko, L.V.; Saranchuk, V.I. [Inst. of Physical, Organic and Coal Chemistry NAS, Donetsk (Ukraine)


    The complex investigation of burnt coal rocks as raw material for hardening alkaline cements reception have been carried out. The hardening composition on the base of pit heap burnt rocks for the grouting of worked-out space in mining conditions have been obtained. It has been shown that burnt rocks activation by blast granulated slag and water glass allowed to obtain the cements of needed strength. The influence of main technological factors on obtained hardening composition properties have been studied. (orig.)

  15. Electrolytic surface hardening of steel,cast iron and aluminium-bronze

    Suhas Keshav Paknikar


    Electrolytic hardening process was developed in USSR in the 1950s. The process was developed but was not commercially exploited. There is no evidence of work done on this process in India. The author has done this original work applied to different materials like steel,cast iron and aluminum-bronze. This paper gives details of microstructural transformations along with hardness value achieved. There is vital scope for this process to become viable for surface hardening and selective hardening of small components.

  16. Multi-MGy Radiation Hardened Camera for Nuclear Facilities

    Girard, Sylvain; Boukenter, Aziz; Ouerdane, Youcef [Universite de Saint-Etienne, Lab. Hubert Curien, UMR-CNRS 5516, F-42000 Saint-Etienne (France); Goiffon, Vincent; Corbiere, Franck; Rolando, Sebastien; Molina, Romain; Estribeau, Magali; Avon, Barbara; Magnan, Pierre [ISAE, Universite de Toulouse, F-31055 Toulouse (France); Paillet, Philippe; Duhamel, Olivier; Gaillardin, Marc; Raine, Melanie [CEA, DAM, DIF, F-91297 Arpajon (France)


    There is an increasing interest in developing cameras for surveillance systems to monitor nuclear facilities or nuclear waste storages. Particularly, for today's and the next generation of nuclear facilities increasing safety requirements consecutive to Fukushima Daiichi's disaster have to be considered. For some applications, radiation tolerance needs to overcome doses in the MGy(SiO{sub 2}) range whereas the most tolerant commercial or prototypes products based on solid state image sensors withstand doses up to few kGy. The objective of this work is to present the radiation hardening strategy developed by our research groups to enhance the tolerance to ionizing radiations of the various subparts of these imaging systems by working simultaneously at the component and system design levels. Developing radiation-hardened camera implies to combine several radiation-hardening strategies. In our case, we decided not to use the simplest one, the shielding approach. This approach is efficient but limits the camera miniaturization and is not compatible with its future integration in remote-handling or robotic systems. Then, the hardening-by-component strategy appears mandatory to avoid the failure of one of the camera subparts at doses lower than the MGy. Concerning the image sensor itself, the used technology is a CMOS Image Sensor (CIS) designed by ISAE team with custom pixel designs used to mitigate the total ionizing dose (TID) effects that occur well below the MGy range in classical image sensors (e.g. Charge Coupled Devices (CCD), Charge Injection Devices (CID) and classical Active Pixel Sensors (APS)), such as the complete loss of functionality, the dark current increase and the gain drop. We'll present at the conference a comparative study between these radiation-hardened pixel radiation responses with respect to conventional ones, demonstrating the efficiency of the choices made. The targeted strategy to develop the complete radiation hard camera

  17. Nucleation and growth of titanium aluminide in an explosion-welded laminate composite

    Bataev, I. A.; Bataev, A. A.; Mali, V. I.; Pavlyukova, D. V.; Yartsev, P. S.; Golovin, E. D.


    Processes of nucleation and growth of titanium aluminide in a 23-layer aluminum-titanium composite produced by explosion welding have been studied. In the vortex zones of seven upper welds, microvolumes of melted metal whose microhardness is ˜5500 MPa have been revealed, which corresponds to the microhardness of the intermetallic compound Al3Ti. No formation of titanium aluminide in welded junctions that were not subjected to additional heat treatment has been revealed by X-ray diffraction. The holding of the composites at 630°C is accompanied by the formation of interlayers of intermetallic compounds of the Al3Ti type. Intermetallic compounds of two morphological types are formed in the welds. In the regions of vortex zones, compact precipitates of Al3Ti are formed; in the other regions of the welds, intermetallic compounds in the form of a film are precipitated. The intermetallic compounds of the first type grow more rapidly and in final account absorb the precipitates of the film type. The activation of diffusion in the upper junctions that occurs upon heating of the welded composites is favored by the nonequilibrium state of the material caused by the strain hardening of the initial samples. In the welds located deeper than the 13th layer, no signs of the formation of compact intermetallic compounds have been revealed upon the annealing for 5 h and less.

  18. Experimental investigation of laser peening on Ti17 titanium alloy for rotor blade applications

    Hongchao, Qiao, E-mail:


    Highlights: • Laser peening on Ti17 titanium alloys is investigated. • Roughness and residual stress value were grown on laser energy and impact times. • Hardened layer depth increases significantly with laser peening impact times. • Laser peening is effectively in lower fatigue stress level. • Laser peening makes the microstructures evolution. - Abstract: Laser peening is an innovative surface treatment technique, and can significantly improve the mechanical performance of metallic components. To investigate the fatigue life of Ti17 titanium alloy by laser peening, laser peening experiment was undertaken using Nd:YAG laser system with the pulse-width of 15 ns and max pulse-energy of 7 J. Firstly, the mechanical properties and microstructure with different laser peening parameters were investigated, which were measured and observed by Vickers indenter, X-ray diffraction, scanning electron microscope and transmission electron microscope. Micro-hardness and compressive residual stress distribution was remarkably improved. High-density dislocations and fine-grains were observed in the surface layer. Then, several stress levels were chosen to be applied on the tension and compression fatigue specimens. The fatigue life and fracture mechanism of the specimens without- and with-laser peened were compared, and the strengthening mechanism was indicated by analyzing the effects on the microstructure and residual stress evolution. The results demonstrate that laser peening could effectively improve the fatigue life of Ti17 titanium alloy.

  19. Organoapatites: materials for artificial bone. II. Hardening reactions and properties.

    Stupp, S I; Mejicano, G C; Hanson, J A


    This article reports on chemical reactions and the properties they generated in artificial bone materials termed "organoapatites." These materials are synthesized using methodology we reported in the previous article of this series. Two different processes were studied here for the transition from organoapatite particles to implants suitable for the restoration of the skeletal system. One process involved the hardening of powder compacts by beams of blue light derived from a lamp or a laser and the other involved pressure-induced interdiffusion of polymers. In both cases, the hardening reaction involved the formation of a polyion complex between two polyelectrolytes. In the photo-induced reaction an anionic electrolyte polymerizes to form the coulombic network and in the pressure-induced one, pressure forms the complex by interdiffusion of two polyions. Model reactions were studied using various polycations. Based on these results the organoapatite selected for the study was that containing dispersed poly(L-lysine) and sodium acrylate as the anionic monomer. The organomineral particles can be pressed at room temperature into objects of great physical integrity and hydrolytic stability relative to anorganic controls. The remarkable fact about these objects is that intimate molecular dispersion of only 2-3% by weight organic material provides integrity to the mineral network in an aqueous medium and also doubles its tensile strength. This integrity is essentially nonexistent in "anorganic" samples prepared by the same methodology used in organoapatite synthesis. The improvement in properties was most effectively produced by molecular bridges formed by photopolymerization. The photopolymerization leads to the "hardening" of pellets prepared by pressing of organoapatite powders. The reaction was found to be more facile in the microstructure of the organomineral, and it is potentially useful in the surgical application of organoapatites as artificial bone.

  20. Effect of hardening method and structure of linking bridges on strength of water glass moulding sands

    Stachowicz, M.; K. Granat


    The paper presents examination results of the effect of four hardening methods on structure of linking bridges in sandmixes containing hydrated sodium silicate. Test pieces prepared of the moulding sands containing 2.5 % of a binder with molar module between 2.4 and 2.6 were hardened with carbon dioxide, dried traditionally in an oven and hardened with microwaves at 2.54 GHz or using a combination of the CO2 process and microwave heating. It was revealed that the hardening method influences s...

  1. Optimizing the Thermal Regime During the Acceleration of Concrete’s Hardening

    Vladimir Corobceanu


    Full Text Available Researches conducted at the Faculty of Construction in Jassy showed several factors that may help finding technical solutions which will make possible to economically apply acceleration procedures of concrete hardening by thermal treatment with solar energy. It has to be mentioned the fact that the thermal treatment do not exclude, but it is based on the acceleration methods of concrete hardening through composition with or without the usage of different additives -- plasticizer type (to reduce the quantity of water from the concrete and accelerators for cement binding or hardening. These methods also take into account the climate where the process of hardening takes place.

  2. Electron beam surface hardening of 42CrMo4 steel

    Jokinen, T.; Meuronen, I. [Valmet Aviation Industries, Linnavuori (Finland). Engine Maintenance


    A study is reported in this paper which aims to find the proper parameters of an electron beam machine for using electron beam (EB) hardening on 42CrMo4 steel. Extended service life for engineering components depends on hard, wear resistant surfaces combined with tough base materials. EB hardening is particularly suitable to local treatment of complex components. Although surface hardening of 42CrMo4 steel was successful, careful optimization of process parameters and the hardened layer are required. (UK).

  3. Radiation-Hardened Memristor-based Memory for Extreme Environments Project

    National Aeronautics and Space Administration — NASA space exploration missions require radiation-hardened memory technologies that can survive and operate over a wide temperature range. Memristors...

  4. Effect of dynamic strain aging on isotropic hardening in low cycle fatigue for carbon manganese steel

    Huang, Zhi Yong, E-mail: [Sichuan University, School of Aeronautics and Astronautics, No. 29 Jiuyanqiao Wangjiang Road, Chengdu 610064 (China); Chaboche, Jean-Louis [ONERA, DMSM, 29 avenue de la Division Lecerc, F-92320 Chatillon (France); Wang, Qing Yuan [Sichuan University, School of Aeronautics and Astronautics, No. 29 Jiuyanqiao Wangjiang Road, Chengdu 610064 (China); Wagner, Danièle; Bathias, Claude [Université ParisOuest Nanterre La Défense (France)


    Carbon–manganese steel A48 (French standard) is used in steam generator pipes of nuclear reactor pressure vessels at high temperatures (about 200 °C). The steel is sensitive to dynamic strain aging in monotonic tensile test and low cycle fatigue test at certain temperature range and strain rate. Its isotropic hardening behavior observed from experiments has a hardening, softening and hardening evolution with the effect of dynamic strain aging. The isotropic hardening model is improved by coupling the dislocation and dynamic strain aging theory to describe the behavior of A48 at 200 °C.

  5. Hardening mechanisms in a dynamic strain aging alloy, Hastelloy X, during isothermal and thermomechanical cyclic deformation

    Miner, R. V.; Castelli, M. G.


    The relative contributions of the hardening mechanisms in Hastelloy X during cyclic deformation were investigated by conducting isothermal cyclic deformation tests within a total strain range of +/-0.3 pct and at several temperatures and strain rates, and thermomechanical tests within several different temperature limits. The results of the TEM examinations and special constant structure tests showed that the precipitation on dislocations of Cr23C6 contributed to hardening, but only after sufficient time above 500 C. Solute drag alone produced very considerable cyclic hardening. Heat dislocation densities, peaking around 10 exp 11 per sq cm, were found to develop at temperatures producing the greatest cyclic hardening.

  6. A new ester hardener for moulding sands with water glass having slower activity

    K. Major-Gabryś


    Full Text Available The article takes into consideration the researches concerning inputting the new hardener to moulding sands with water glass, carried out in ester technology. Investigations are continuation of works connected to hardener based on carbonic acid’s esters, that significantly upgrades the ability of these moulding sands to mechanical reclamation. Its’ nuisance is short vitality. This is why, new investigations were taken to elaborate another hardener keeping the positive characteristics of the previous one and allowing the wider usage of technologies of loose self-hardened moulding sands with water glass.

  7. Development of a Flexible Laser Hardening & Machining Center and Proof of Concept on C-45 Steel

    Bouquet, Jan; Van Camp, Dries; Vanhove, Hans; Clijsters, Stijn; Amirahmad, Mohammadi; Lauwers, Bert

    The production of hardened precision parts is conventionally done in 3 steps. Rough machining of a workpiece in soft stage is followed by a hardening step, usually a batch process, and finalized by a hard machining finishing step. To omit the inevitable time delay and loss of accuracy because of part re-clamping, these steps should be incorporated within one flexible machining center. This paper describes the development of this machining center which allowsmachining and laser hardening in one setup, followed by a proof of concept for hardening C45 steel on this setup.

  8. Rationale simplified hardening training and recreational complexes future teachers

    Verbludov I.B.


    Full Text Available Distribution in the modern world epidemiological diseases are influenza and acute respiratory viral infections requires a search for simplified, effective preventive means. The main direction of prevention of these diseases is to strengthen and enhance the activities of the immune system. Strengthening the protective systems of the body is directly related to the constant holding of different types of hardening. This study illustrates the possibility of using quenching air and water in the independent exercise training and recreational facilities in all conditions of students.

  9. Bake hardening behavior of TRIP and DP steels

    Jicheng Zhang; Renyu Fu; Mei Zhang; Rendong Liu; Xicheng Wei; Lin Li


    The bake hardening (BH) behavior of transformation-induced plasticity (TRIP) and dual-phase (DP) steels after different prestrains was studied. The experimental results indicate that TRIP steel exhibits good BH ability while DP steel does not, and prestrain displays a strong effect on the BH values of both steels. The comparison of microstructures of the two steels showed that the hard second phase in the matrix might be harmful to the BH ability. For deformed specimens, baking resulted in a loss of uniform elongation, but there was no obvious decrease in uniform elongation for unprestrained specimens.

  10. The development of radiation hardened robot for nuclear facility

    Kim, Seung Ho; Jung, Seung Ho; Kim, Byung Soo and others


    The work conducted in this stage covers development of core technology of tele-robot system including monitoring technique in high-level radioactive area, tele-sensing technology and radiation-hardened technology for the non-destructive tele-inspection system which monitors the primary coolant system during the normal operations of PHWR(Pressurized Heavy Water Reactor) NPPs and measures the decrease of bending part of feeder pipe during overall. Based on the developed core technology, the monitoring mobile robot system of the primary coolant system and the feeder pipe inspecting robot system are developed.

  11. New Stainless Steel Alloys for Low Temperature Surface Hardening?

    Christiansen, Thomas Lundin; Dahl, Kristian Vinter; Somers, Marcel A. J.


    The present contribution showcases the possibility for developing new surface hardenable stainless steels containing strong nitride/carbide forming elements (SNCFE). Nitriding of the commercial alloys, austenitic A286, and ferritic AISI 409 illustrates the beneficial effect of having SNCFE present...... in the stainless steel alloys. The presented computational approach for alloy design enables “screening” of hundreds of thousands hypothetical alloy systems by use of Thermo-Calc. Promising compositions for new stainless steel alloys can be selected based on imposed criteria, i.e. facilitating easy selection...

  12. Ductility and work hardening in nano-sized metallic glasses

    Chen, D. Z., E-mail: [Division of Engineering and Applied Sciences, California Institute of Technology, Pasadena, California 91125 (United States); Gu, X. W. [Department of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125 (United States); An, Q.; Goddard, W. A. [Materials and Process Simulation Center, California Institute of Technology, Pasadena, California 91125 (United States); Greer, J. R. [Division of Engineering and Applied Sciences, California Institute of Technology, Pasadena, California 91125 (United States); The Kavli Nanoscience Institute, California Institute of Technology, Pasadena, California 91125 (United States)


    In-situ nano-tensile experiments on 70 nm-diameter free-standing electroplated NiP metallic glass nanostructures reveal tensile true strains of ∼18%, an amount comparable to compositionally identical 100 nm-diameter focused ion beam samples and ∼3 times greater than 100 nm-diameter electroplated samples. Simultaneous in-situ observations and stress-strain data during post-elastic deformation reveal necking and work hardening, features uncharacteristic for metallic glasses. The evolution of free volume within molecular dynamics-simulated samples suggests a free surface-mediated relaxation mechanism in nano-sized metallic glasses.

  13. Fatigue Hardening and Nucleation of Persistent Slip Bands in Copper

    Pedersen, Ole Bøcker; Winter, A. T.


    that there is a large volume fraction of obstacles to plastic flow which are essentially non-deformable and give rise to inclusion stresses of considerable magnitude. The much lower hardening rates in cycles after saturation when persistent slip bands have formed suggest a lower volume fraction of obstacles......, as is observed by transmission electron microscopy. A simple composite model involving an inclusion stress, a bowing stress and a passing, stress accounts for the workhardening rates semi-quantitatively in terms of observed dislocation microstructures. Possible implications for polycrystals are considered....

  14. Thermomechanical hardening of stable and metastable austenitic steels

    Baraz, V. R.; Gladkovskii, S. V.; Ishina, E. A.


    Phase composition, mechanical properties, and variation of the density of cold-deformed Fe-Cr-Ni-Mn steels differing in the stability of austenite are studied. A comparative analysis of formation of phase composition and accumulation of discontinuities in the process of drawing of stable and metastable austenitic steels is performed. The effect of post-deformation annealing on the variation of the density and mechanical properties is considered. The capacity for recovery of the density is shown to be correlated with the resistance of the studied thermomechanically hardened steels to fatigue fracture. The determined dependences are explained.

  15. Ferroelectric memories: A possible answer to the hardened nonvolatile question

    Messenger, G.C.; Coppage, F.N.


    Ferroelectric memory cells have been fabricated using a process compatible with semiconductor VLSI (Very Large-Scale Integration) manufacturing techniques which are basically nonvolatile and radiation hard. The memory can be made NDRO (Nondestructive Readout) for strategic systems using several techniques; the most practical is probably a rapid read/restore in combination with EDAC software. This memory can replace plated wire and will have substantial advantages in cost, weight, size, power and speed. It provides a practical cost-competitive solution to the need for nonvolatile RAM in all hardened tactical, avionic, and space systems.

  16. Interaction between alloying and hardening of cast iron surface

    刘政军; 郝雪枫; 傅迎庆; 牟力军


    To improve wear resistance of surface will increase the service life of gray cast iron directly. This paper presents that gray cast iron surface coated with alloy powder is locally remelted by TIG arc to increase the wear resistance. The influences of arc current and scanning rate etc on surface properties are found. Under different conditions, the microstructure, hardness and wear resistance of remelted layer are analyzed and measured. The results indicate that the gray cast iron surface can be strengthened by TIG arc local remelting treatment. Especially, surface alloying hardening effect is best and surface properties are improved remarkably.

  17. Structure and mechanical properties of high-temperature titanium alloys after rapid heat treatment

    Ivasishin, O.M. (Inst. for Metal Physics, Kiev (Ukraine)); Luetjering, G. (Technical Univ. Hamburg-Harburg, Hamburg (Germany))


    In this study a new approach to optimizing the mechanical properties of high-temperature titanium alloys was developed. It is based on using rapid heating of equiaxed structures into the [beta]-field to achieve a fine [beta] grain size (less than or equal to 100 [mu]m), transforming on subsequent cooling into a fully lamellar structure. This fine [beta] grain size is an order of magnitude smaller than the grain sizes achieved by conventional furnace [beta]-treatment. Structures and mechanical properties (tensile, fatigue and creep) of high temperature alloys after rapid and conventional furnace heat treatments were compared. The results are discussed in terms of structure-property relationships. (orig.)

  18. Influence of Plastic Deformation on Low Temperature Surface Hardening of Austenitic and Precipitation Hardening Stainless Steels by Gaseous Nitriding

    Bottoli, Federico; Winther, Grethe; Christiansen, Thomas Lundin


    This article addresses an investigation of the influence of plastic deformation on low temperature surface hardening by gaseous nitriding of three commercial austenitic stainless steels: AISI 304, EN 1.4369 and Sandvik Nanoflex® with various degrees of austenite stability. The materials were...... plastically deformed to different equivalent strains by uniaxial tension. Gaseous nitriding of the strained material was performed in ammonia gas at atmospheric pressure at 703 K (430 °C) and 693 K (420 °C) depending on the material. Microstructural characterization of the as-deformed states and the nitrided...

  19. Reinforcement of the bulk crowns excavator technology by dispersion hardening of titanium carbide to increase wear resistance

    Chumanov, I.; Anikeev, A.; Chumanov, V.


    Dispersed particles embedded in the metal, improve the mechanical properties, particularly wear resistance. Introduction of the metal particles in a controlled and their distribution is difficult because of the density difference and the metal particles introduced. This article provides a method for the introduction of particles in the volume of metal, it contains a proposed strengthening technique described experiment course. During the experiment, the volume-reinforced castings from wear-resistant steel, the results of studies of the microstructure by optical and scanning electron microscopy, and mechanical tests of prototypes have been obtained.

  20. 钛的激光渗氧硬化研究%Study of Laser Oxidizing for Titanium Hardening

    张坤; 罗耕星; 陈光南



  1. Implicit numerical integration for a kinematic hardening soil plasticity model

    Rouainia, M.; Muir Wood, D.


    Soil models based on kinematic hardening together with elements of bounding surface plasticity, provide a means of introducing some memory of recent history and stiffness variation in the predicted response of soils. Such models provide an improvement on simple elasto-plastic models in describing soil behaviour under non-monotonic loading. Routine use of such models requires robust numerical integration schemes. Explicit integration of highly non-linear models requires extremely small steps in order to guarantee convergence. Here, a fully implicit scheme is presented for a simple kinematic hardening extension of the Cam clay soil model. The algorithm is based on the operator split methodology and the implicit Euler backward integration scheme is proposed to integrate the rate form of the constitutive relations. This algorithm maintains a quadratic rate of asymptotic convergence when used with a Newton-Raphson iterative procedure. Various strain-driven axisymmetric triaxial paths are simulated in order to demonstrate the efficiency and good performance of the proposed algorithm.

  2. Folding and faulting of strain-hardening sedimentary rocks

    Johnson, A.M.


    The question of whether single- or multi-layers of sedimentary rocks will fault or fold when subjected to layer-parallel shortening is investigated by means of the theory of elastic-plastic, strain-hardening materials, which should closely describe the properties of sedimentary rocks at high levels in the Earth's crust. The most attractive feature of the theory is that folding and faulting, intimately related in nature, are different responses of the same idealized material to different conditions. When single-layers of sedimentary rock behave much as strain-hardening materials they are unlikely to fold, rather they tend to fault, because contrasts in elasticity and strength properties of sedimentary rocks are low. Amplifications of folds in such materials are negligible whether contacts between layer and media are bonded or free to slip for single layers of dolomite, limestone, sandstone, or siltstone in media of shale. Multilayers of these same rocks fault rather than fold if contacts are bonded, but they fold readily if contacts between layers are frictionless, or have low yield strengths, for example due to high pore-water pressure. Faults may accompany the folds, occurring where compression is increased in cores of folds. Where there is predominant reverse faulting in sedimentary sequences, there probably were few structural units. ?? 1980.

  3. Discrepant hardening observed in cosmic-ray elemental spectra

    Ahn, H S; Bagliesi, M G; Beatty, J J; Bigongiari, G; Childers, J T; Conklin, N B; Coutu, S; DuVernois, M A; Ganel, O; Han, J H; Jeon, J A; Kim, K C; Lee, M H; Lutz, L; Maestro, P; Malinin, A; Marrocchesi, P S; Minnick, S; Mognet, S I; Nam, J; Nam, S; Nutter, S L; Park, I H; Park, N H; Seo, E S; Sina, R; Wu, J; Yang, J; Yoon, Y S; Zei, R; Zinn, S Y; 10.1088/2041-8205/714/1/L89


    The balloon-borne Cosmic Ray Energetics And Mass (CREAM) experiment launched five times from Antarctica has achieved a cumulative flight duration of about 156 days above 99.5% of the atmosphere. The instrument is configured with complementary and redundant particle detectors designed to extend direct measurements of cosmic-ray composition to the highest energies practical with balloon flights. All elements from protons to iron nuclei are separated with excellent charge resolution. Here we report results from the first two flights of ~70 days, which indicate hardening of the elemental spectra above ~200 GeV/nucleon and a spectral difference between the two most abundant species, protons and helium nuclei. These results challenge the view that cosmic-ray spectra are simple power laws below the so-called knee at ~1015 eV. This discrepant hardening may result from a relatively nearby source, or it could represent spectral concavity caused by interactions of cosmic rays with the accelerating shock. Other possible ...

  4. Dislocation Starvation and Exhaustion Hardening in Mo-alloy Nanofibers

    Chisholm, Claire [University of California, Berkeley & LBNL; Bei, Hongbin [ORNL; Lowry, M. B. [University of California, Berkeley; Oh, Jason [Hysitron, Inc., MN; Asif, S.A. Syed [Hysitron, Inc., MN; Warren, O. [Hysitron, Inc., MN; Shan, Zhiwei [Xi' an Jiaotong University, China & Hysitron, Inc., MN; George, Easo P [ORNL; Minor, Andrew [University of California, Berkeley & LBNL


    The evolution of defects in Mo alloy nanofibers with initial dislocation densities ranging from 0 to 1.6 1014 m2 were studied using an in situ push-to-pull device in conjunction with a nanoindenter in a transmission electron microscope. Digital image correlation was used to determine stress and strain in local areas of deformation. When they had no initial dislocations the Mo alloy nanofibers suffered sudden catastrophic elongation following elastic deformation to ultrahigh stresses. At the other extreme fibers with a high dislocation density underwent sustained homogeneous deformation after yielding at much lower stresses. Between these two extremes nanofibers with intermediate dislocation densities demonstrated a clear exhaustion hardening behavior, where the progressive exhaustion of dislocations and dislocation sources increases the stress required to drive plasticity. This is consistent with the idea that mechanical size effects ( smaller is stronger ) are due to the fact that nanostructures usually have fewer defects that can operate at lower stresses. By monitoring the evolution of stress locally we find that exhaustion hardening causes the stress in the nanofibers to surpass the critical stress predicted for self-multiplication, supporting a plasticity mechanism that has been hypothesized to account for the rapid strain softening observed in nanoscale bcc materials at high stresses.

  5. Atomistic interpretation of solid solution hardening from spectral analysis.

    Plendl, J N


    From analysis of a series of vibrational spectra of ir energy absorption and laser Raman, an attempt is made to interpret solid solution hardening from an atomistic point of view for the system CaF(2)/SrF(2). It is shown to be caused by the combined action of three atomic characteristics, i.e., their changes as a function of composition. They are deformation of the atomic coordination polyhedrons, overlap of the outer electron shells of the atom pairs, and the ratio of the ionic to covalent share of binding. A striking nonlinear behavior of the three characteristics, as a function of composition, gives maximum atomic bond strength to the 55/45 position of the system CaF(2)/SrF(2), in agreement with the measured data of the solid solution hardening. The curve for atomic bond strength, derived from the three characteristics, is almost identical to the curve for measured microhardness data. This result suggests that the atomistic interpretation, put forward in this paper, is correct.

  6. Microstructural aspects and wear behavior of sinter hardened distaloy HP

    Sheikhi Moghaddam, K.; Ghambari, M.; Farhangi, H. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran (Iran, Islamic Republic of); Solimanjad, N.; Bergmark, A. [Hoeganaes AB, Bruksgatan, Hoeganaes (Sweden); Khorsand, H. [K.N. Toosi University, Tehran (Iran, Islamic Republic of)


    Effect of cooling rate during sinter hardening on the microstructure and wear behavior of sintered steel grade Distaloy HP has been studied. Wear performances are closely related to macro and micro hardness of the materials. Dry sliding wear tests have been conducted using a reciprocating pin on flat wear testing machine under normal loads of 25, 35 and 45N and at a constant speed of 0.3 m/s. The samples were sinter hardened at different cooling rates 0.5-3 C/s in order to investigate the influence of microstructure and hardness on wear behavior. It has been shown that, sintering process and cooling rate change the microstructure and hence the hardness and wear behavior of the material. The best wear resistance was detected at a cooling rate of 3 C/s. At this cooling rate the material had an almost martensitic microstructure and the wear rate was some how independent of the applied load. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)


    D.G. Lee; K.C.Jang; J.M. Kuk; I.S. Kim


    Rotary bending fatigue tests were carried out with two kinds of materials, S43C and S50C, using the front engine and front drive shaft (FF shaft) of vehicle. The specimens were induction hardened about 1.0mm depth from the specimen surface, and the hardness value on the surface was about HRC56-60. The tested environment temperatures were -30, 25 and 80℃ in order to look over effect of the induction hardening and the environmental temperatures on the fatigue characteristics. The fatigue limit of induction hardened specimens increased more about 45%than non-hardened specimens showing that the endurances of S43C and S50C were 98.1 and 107.9MPa in non-hardened samples, 147.1 and 156.9MPa in hardened samplesrespectably. The maximum tensile and compressive stress on the small circular defect was about +250 and -450MPa respectively when circular defect is situated on top and bottom. The fatigue life increased 80, 25and -30℃ in order regardless of hardening. In comparison of the fatigue lives on the basis of tested result at 25℃, the fatigue lives of non-hardened specimens decreased about 35%, but that of hardened specimens decreased about only 5% at 80℃ more than at 25℃. And fatigue life of non-hardened and hardened specimens were about 110% and 120% higher at -30℃ than that of 25℃. Based on the result of stress distribution near the defect, the tensile and compressive stress repeatedly generated by load direction were the largest on the small circular defect due to the stress concentration.

  8. Increased chondrocyte adhesion on nanotubular anodized titanium.

    Burns, Kevin; Yao, Chang; Webster, Thomas J


    Previous studies have demonstrated increased osteoblast (bone-forming cells) functions (including adhesion, synthesis of intracellular collagen, alkaline phosphatase activity, and deposition of calcium-containing minerals) on titanium anodized to possess nanometer features compared with their unanodized counterparts. Such titanium materials were anodized to possess novel nanotubes also capable of drug delivery. Since titanium has not only experienced wide spread commercial use in orthopedic but also in cartilage applications, the objective of the present in vitro study was for the first time to investigate chondrocyte (cartilage synthesizing cells) functions on titanium anodized to possess nanotubes. For this purpose, titanium was anodized in dilute hydrofluoric acid at 20 V for 20 min. Results showed increased chondrocyte adhesion on anodized titanium with nanotube structures compared with unanodized titanium. Importantly, the present study also provided evidence why. Since material characterization studies revealed significantly greater nanometer roughness and similar chemistry as well as crystallinity between nanotubular anodized and unanodized titanium, the results of the present study highlight the importance of the nanometer roughness provided by anodized nanotubes on titanium for enhancing chondrocyte adhesion. In this manner, the results of the present in vitro study indicated that anodization might be a promising quick and inexpensive method to modify the surface of titanium-based implants to induce better chondrocyte adhesion for cartilage applications.


    刘晓晨; 孙东涛; 李晓红


    目的:研究新型钛合金在模拟口腔环境中的表面粗糙度和反射率的改变,为口腔内存在钛合金种植体或戴用钛合金义齿的病人给予临床指导。方法:制备好的钛合金试件随机分为8组。每组试件在处理前,以及处理后1mo、2mo时分别测量试件表面粗糙度和反射率,应用SPSS统计软件分析所得结果。结果:刷洗组试件相对不刷洗组试件表面粗糙度和反射率增大,具有统计学意义(P<0.05);pH值和氟离子浓度两因素之间存在交互作用(P<0.05),具有统计学意义。结论:钛合金试件的腐蚀程度主要与实验周期、是否刷洗,以及氟离子浓度和pH值的交互作用有关。%Objective:To Study the variation of the surface roughness and reflectivity of a new type of titanium alloy in simulated oral environment surface,and provide clinical guidance for patients who have received titanium implant therapy or worn denture. Methods:The prepared titanium chips were divided into eight groups randomly. Surface roughness and reflectivity of each specimen were examined before the treatment,on the 30th day and on the 60th day after the treatment. Results:The surface roughness and reflectivity of the brushing group had statistically significant compared with the non-brushing group ( P<0 . 05 ) . There was interaction between pH and fluoride ionic concentration ( P<0 . 05 ) . Conclusion:pH、fluoride ionic concentration、tooth brushing and experimental session all have an effect on the degree of corrosion of the titanium alloy specimen.

  10. Continuous Hardening During Isothermal Aging at 723 K (450 °C) of a Precipitation Hardening Stainless Steel

    Celada-Casero, Carola; Chao, Jesús; Urones-Garrote, Esteban; San Martin, David


    The isothermal aging behavior of a cold-rolled precipitation hardening stainless steel has been studied at 723 K (450 °C) for holding times up to 72 hours. The precipitation hardening has been investigated using microhardness Vickers (Hv), thermoelectric power (TEP) measurements, and tensile testing. Microhardness compared to TEP measurements is more sensitive to detect the initial stages of aging. Two precipitation regimes have been observed: the first one related to the formation of Cu-clusters for aging times below 1 hour and a second one associated with formation of Ni-rich precipitates. The results show that the material exhibits an outstanding continuous age strengthening response over the aging time investigated, reaching a hardness of 710 ± 4 HV1 and an ultimate tensile strength ( σ UTS) of 2.65 ± 0.02 GPa after 72 hours. Engineering stress-plastic strain curves reveal that the strength increases and the ductility decreases as the aging time increases. However, after prolonged holding times (24-72 hours) and, although small, a rise in both the strength and the total elongation is observed. The precipitation kinetics can be well predicted over the entire range of aging times by the Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation. Finally, a reliable linear hardness-yield strength correlation has been found, which enables a rapid evaluation of the strength from bulk hardness measurements.

  11. Antimicrobial titanium/silver PVD coatings on titanium

    Thull Roger


    Full Text Available Abstract Background Biofilm formation and deep infection of endoprostheses is a recurrent complication in implant surgery. Post-operative infections may be overcome by adjusting antimicrobial properties of the implant surface prior to implantation. In this work we described the development of an antimicrobial titanium/silver hard coating via the physical vapor deposition (PVD process. Methods Coatings with a thickness of approximately 2 μm were deposited on titanium surfaces by simultaneous vaporisation of both metals in an inert argon atmosphere with a silver content of approximately 0.7 – 9% as indicated by energy dispersive X-ray analysis. On these surfaces microorganisms and eukaryotic culture cells were grown. Results The coatings released sufficient silver ions (0.5–2.3 ppb when immersed in PBS and showed significant antimicrobial potency against Staphylococcus epidermis and Klebsiella pneumoniae strains. At the same time, no cytotoxic effects of the coatings on osteoblast and epithelial cells were found. Conclusion Due to similar mechanical performance when compared to pure titanium, the TiAg coatings should be suitable to provide antimicrobial activity on load-bearing implant surfaces.

  12. Beta-carotene

    ... patches on the tongue and mouth called oral leukoplakia. Taking beta-carotene by mouth for up to 12 months seems to decrease symptoms of oral leukoplakia. Osteoarthritis. Beta-carotene taken by mouth may prevent ...

  13. Strain hardening as an indicator of bread-making performance: A review with discussion

    Vliet, van T.


    Since strain hardening has been proposed as an important quality indicator of dough with respect to bread-making performance, a large body of experimental support for this concept has been published. Nevertheless, some questions remain with respect to the use of the concept of strain hardening. This

  14. Numerical Simulation of Stresses due to Solid State Transformations : The Simulation of Laser Hardening

    Geijselaers, H.J.M.


    The properties of many engineeringmaterialsmay be favourablymodified by application of a suitable heat treatment. Examples are precipitation hardening, tempering and annealing. One of the most important treatments is the transformation hardening of steel. Steel is an alloy of iron and carbon. At roo

  15. Physical and Thermodynamical Properties of Water Phases in Hardening Portland Cement Systems

    Hansen, T. Bæk

    The present study is devoted to the description of water phases in hardening portland cement paste systems containing a significant amount of micro-filler and having a low to moderate water/powder ratio. Emphasis has been placed on the early stages of the hardening process....

  16. Plant resistance to cold stress: Mechanisms and environmental signals triggering frost hardening and dehardening

    Erwin H Beck; Richard Heim; Jens Hansen


    This introductory overview shows that cold, in particular frost, stresses a plant in manifold ways and that the plant’s response, being injurious or adaptive, must be considered a syndrome rather than a single reaction. In the course of the year perennial plants of the temperate climate zones undergo frost hardening in autumn and dehardening in spring. Using Scots pine (Pinus sylvestris L.) as a model plant the environmental signals inducing frost hardening and dehardening, respectively, were investigated. Over 2 years the changes in frost resistance of Scots pine needles were recorded together with the annual courses of day-length and ambient temperature. Both act as environmental signals for frost hardening and dehardening. Climate chamber experiments showed that short day-length as a signal triggering frost hardening could be replaced by irradiation with far red light, while red light inhibited hardening. The involvement of phytochrome as a signal receptor could be corroborated by respective night-break experiments. More rapid frost hardening than by short day or far red treatment was achieved by applying a short period (6 h) of mild frost which did not exceed the plant’s cold resistance. Both types of signals were independently effective but the rates of frost hardening were not additive. The maximal rate of hardening was – 0.93°C per day and frost tolerance of < – 72°C was achieved. For dehardening, temperature was an even more effective signal than day-length.

  17. An Evaluation of the Corrosion and Mechanical Performance of Interstitially Surface Hardened Stainless Steel


    metallography and microhardness profiling. The corrosion performance of the hardened surface is assessed using electrochemical potentiodynamic testing to...cracking resistance, and galling performance. Metallurgical Evaluation: Microhardness testing was conducted for Processes B1 and B2, which represent...incorporated experimental testing conducted on 316L stainless steel that has been surface hardened using available commercial techniques, using both

  18. Optimization of tensile strain-hardening cementhious composites for tensile strain capacity

    Shionaga, R.; Pansuk, W.; Grunewald, S.; den Uijl, J.A.; Walraven, J.C.


    The synergistic action of a cementitious matrix and fibres can result in strain hardening in tension. The accompanied tensile strain capacity can be an important design parameter for strain-hardening cementitious composites in order to prevent the localization in a single crack and to assure that th

  19. [Optimal coefficient of overlap of light spots during laser hardening of medical instruments].

    Stepanova, G A; Pogibenko, A V; Gerasev, G P


    The optimum coefficient of light spot intercepts in the course of laser hardening medical instruments is determined for the case when there are no unirradiated sites on the surface under treatment. The increase in the light spot diameter during irradiation has been shown to be followed by more rapid expansion of the hardened area in comparison with the one of the tempered zone.

  20. Strain hardening as an indicator of bread-making performance: A review with discussion

    Vliet, van T.


    Since strain hardening has been proposed as an important quality indicator of dough with respect to bread-making performance, a large body of experimental support for this concept has been published. Nevertheless, some questions remain with respect to the use of the concept of strain hardening. This

  1. The effects of x-ray beam hardening on detective quantum efficiency and radiation dose.

    Wong, Molly Donovan; Wu, Xizeng; Liu, Hong


    The goal of this preliminary study was to investigate the effects of x-ray beam hardening on the detective quantum efficiency (DQE) and the radiation dose of an inline x-ray imaging system. The ability to decrease the risk of harmful radiation to the patient without compromising the detection capability would more effectively balance the tradeoff between image quality and radiation dose, and therefore benefit the fields of diagnostic x-ray imaging, especially mammography. The DQE and the average glandular dose were both calculated under the same experimental conditions for a range of beam hardening levels, corresponding to no added beam hardening and two thicknesses each of Rhodium (Rh) and Molybdenum (Mo) filters. The dose calculation results demonstrate a reduction of 15% to 24% for the range of beam hardening levels. The comparison of all quantities comprising the DQE exhibit very close correlation between the results obtained without added beam hardening to the results corresponding to the range of beam hardening levels. For the specific experimental conditions utilized in this preliminary study, the results are an indication that the use of beam hardening holds the potential to reduce the radiation dose without decreasing the performance of the system. Future studies will seek to apply this method in a clinical environment and perform a comprehensive image quality evaluation, in an effort to further evaluate the potential of beam hardening to balance the tradeoff between dose and image quality.

  2. Effect of hardening method and structure of linking bridges on strength of water glass moulding sands

    M. Stachowicz


    Full Text Available The paper presents examination results of the effect of four hardening methods on structure of linking bridges in sandmixes containing hydrated sodium silicate. Test pieces prepared of the moulding sands containing 2.5 % of a binder with molar module between 2.4 and 2.6 were hardened with carbon dioxide, dried traditionally in an oven and hardened with microwaves at 2.54 GHz or using a combination of the CO2 process and microwave heating. It was revealed that the hardening method influences structure of linking bridges and is correlated with mechanical properties of the hardened moulding sands. It was found that strength of the moulding sands microwave-heated for 240 s is approximate to that measured after traditional drying for 120 min at 110 °C. So, the microwave hardening permits significant reduction of the process time, comparable to the CO2 hardening, at the same time guaranteeing over 10 times higher mechanical properties. Analysis of SEM photographs of the moulding sands hardened with the mentioned methods allow explaining differences in qualitative parameters of the moulding sands and their relation to structures of the created linking bridges.

  3. A MGy Radiation-Hardened Sensor Instrumentation SoC in 65nm CMOS Technology

    Verbeeck, Jens; Cao, Ying; Van Uffelen, Marco; Mont Casellas, Laura; Damiani, Carlo; Meek, Richard; Haist, Bernhard; Steyaert, Michiel; Leroux, Paul


    A radiation-hardened sensor instrumentation SoC is presented in this paper. The SoC is implemented in a standard 65nm CMOS technology, and achieves MGy-level TID radiation hardness through radiation-hardening-by-design.

  4. Parameters Optimization of Plasma Hardening Process Using Genetic Algorithm and Neural Network

    LIU Gu; WANG Liu-ying; CHEN Gui-ming; HUA Shao-chun


    Plasma surface hardening process was performed to improve the performance of the AISI 1045 carbon steel.Experiments were carried out to characterize the hardening qualities.A predicting and optimizing model using genetic algorithm-back propagation neural network(GA-BP) was developed based on the experimental results.The non-linear relationship between properties of hardening layers and process parameters was established.The results show that the GA-BP predicting model is reliable since prediction results are in rather good agreement with measured results.The optimal properties of the hardened layer were deduced from GA.And through multi optimizations,the optimum comprehensive performances of the hardened layer were as follows:plasma arc current is 90 A,hardening speed is 2.2 m/min,plasma gas flow rate is 6.0 L/min and hardening distance is 4.3 mm.It concludes that GA-BP mode developed in this study provides a promising method for plasma hardening parameters prediction and optimization.

  5. Hydrogen content in titanium and a titanium-zirconium alloy after acid etching.

    Frank, Matthias J; Walter, Martin S; Lyngstadaas, S Petter; Wintermantel, Erich; Haugen, Håvard J


    Dental implant alloys made from titanium and zirconium are known for their high mechanical strength, fracture toughness and corrosion resistance in comparison with commercially pure titanium. The aim of the study was to investigate possible differences in the surface chemistry and/or surface topography of titanium and titanium-zirconium surfaces after sand blasting and acid etching. The two surfaces were compared by X-ray photoelectron spectroscopy, secondary ion mass spectroscopy, scanning electron microscopy and profilometry. The 1.9 times greater surface hydrogen concentration of titanium zirconium compared to titanium was found to be the major difference between the two materials. Zirconium appeared to enhance hydride formation on titanium alloys when etched in acid. Surface topography revealed significant differences on the micro and nanoscale. Surface roughness was increased significantly (pzirconium alloy. High-resolution images showed nanostructures only present on titanium zirconium.

  6. Investigation on SS316, SS440C, and Titanium Alloy Grade-5 used as Single Point Cutting Tool

    Mr.Kothakota Suresh Kumar


    Full Text Available The main objective of this work is to find alternative materials for the cutting tools used in turning operations. The conventional materials like tungsten carbide(WC, titanium carbide(TiC, cubic boron nitride (CBN and diamond used as cutting tools for turning operations on lathe are expensive. Titanium grade 5 (Ti-6Al-4V, SS440C/AISI440C and SS316 are some of the materials which satisfy the necessary requirements for turning metals and polymer materials. These materials are machined as per the standard tool signature of high-speed steel tool (HSS and are subjected to necessary heat treatment for hardening and then finish ground. The machined tools thus prepared were used to turn mild steel and aluminium workpieces. The cutting forces at play are determined using lathe tool dynamometer and plotted on a MCD (Merchant’s Circle Diagram. The cutting tools are also subjected to tests to determine tool life, wear and work hardening. It is found that the performance and tool life of SS440C is better and cost effective compared to existing tools. Even though Ti-6Al-4V is comparatively costly it could be used for obtaining good surface finish.

  7. Evaluation of titanium carbide metal matrix composites deposited via laser cladding

    Cavanaugh, Daniel Thomas

    Metal matrix composites have been widely studied in terms of abrasion resistance, but a particular material system may behave differently as particle size, morphology, composition, and distribution of the hardening phase varies. The purpose of this thesis was to understand the mechanical and microstructural effects of combining titanium carbide with 431 series stainless steel to create a unique composite via laser cladding, particularly regarding wear properties. The most predominant effect in increasing abrasion resistance, measured via ASTM G65, was confirmed to be volume fraction of titanium carbide addition. Macrohardness was directly proportional to the amount of carbide, though there was an overall reduction in individual particle microhardness after cladding. The reduction in particle hardness was obscured by the effect of volume fraction carbide and did not substantially contribute to the wear resistance changes. A model evaluating effective mean free path of the titanium carbide particles was created and correlated to the measured data. The model proved successful in linking theoretical mean free path to overall abrasion resistance. The effects of the titanium carbide particle distributions were limited, while differences in particle size were noticeable. The mean free path model did not correlate well with the particle size, but it was shown that the fine carbides were completely removed by the coarse abrasive particles in the ASTM G65 test. The particle morphology showed indications of influencing the wear mode, but no statistical reduction was observed in the volume loss figures. Future studies may more specifically focus on particle morphology or compositional effects of the carbide particles.

  8. Experimental study of self-compacted concrete in hardened state

    Parra Costa, Carlos Jose

    The main aim of this work is to investigate the hardened behaviour of Self-Compacting Concrete (SCC). Self compacting Concrete is a special concrete that can flow in its gravity and fill in the formwork alone to its self-weight, passing through the bars and congested sections without the need of any internal or external vibration, while maintaining adequate homogeneity. SCC avoids most of the materials defects due to bleeding or segregation. With regard to its composition, SCC consists of the same components as traditional vibrated concrete (TC), but in different proportions. Thus, the high amount of superplasticizer and high powder content have to taken into account. The high workability of SCC does not allow to use traditional methods for measuring the fresh state properties, so new tests has developed (slump-flow, V-funnel, L-box, and others). The properties of the hardened SCC, which depend on the mix design, should be different from traditional concrete. In order to study the possible modifications of SCC hardened state properties, a review of the bibliography was done. The state of art was focused on the mechanical behaviour (compressive strength, tension strength and elastic modulus), on bond strength of reinforcement steel, and on material durability. The experimental program consisted in the production of two types of concretes: Self-Compacting Concrete and Traditional Concrete. Four different dosages was made with three different water/cement ratio and two strength types of Portland cement, in order to cover the ordinary strength used in construction. Based on this study it can be concluded that compressive strength of SCC and TC are similar (the differences are lesser than 10%), whereas the tensile strength of TC are up to 18% higher. The values of elastic modulus of both concrete are similar. On the other hand, in the ultimate state the bond strength of SCC and TC is similar, although SCC shows higher bond stiffness in the serviceability state (initial

  9. Hot Machining of Hardened Steels with Coated Carbide Inserts

    M. A. Lajis


    Full Text Available Problem statement: The benefits of easier manufacture of hardened steel components can be substantial in terms of reduced machining costs and lead times compared to the traditional route involving machining of the annealed state followed by heat treatment, grinding/EDM and manual finishing. But machinability of hard material through conventional machining is hindered due to excessive wear of the cutting tools and differently in achieving desired quality of the machined surface. In end milling the cutting tool is not in constant operation and so undergoes a heat cycle during the intermittent cutting. This alternate heating and cooling of the inserts lead to the thermal cracks and subsequently failure of the tool. Approach: This study was conducted to investigate the effect of preheating through inductive heating mechanism in end milling (vertical milling center of AISI D2 hardened steel (56-62 HRC by using coated carbide tool inserts. Apart from preheating, two other machining parameters such as cutting speed and feed were varied while the depth of cut was kept constant. Results: Tool wear phenomenon and machined surface finish were found to be significantly affected by preheating temperature and other two variables. Preheating temperature of 335°C coupled with cutting speed of 40 m min-1, depth of cut of 1.0 mm and feed of 0.02 mm/tooth resulted in a noticeable reduction in tool wear rate leading to a maximum tool life 188.55 min. In addition, cutting speed of 56.57 m min-1 together with feed of 0.044 mm/tooth and depth of cut 1.0 mm at which maximum VMR (9500 mm3 was secured provides a better surface finish with minimum surface roughness 0.25µm leaving a possibility of skipping the grinding and polishing operations for certain applications. Conclusion/Recommendation: Through the end milling of preheated AISI D2 hardened steel by using TiAlN coated carbide cutting tool it can be concluded that an overall enhanced machinability is achievable by

  10. Laser transformation hardening on rod-shaped carbon steel byGaussian beam

    Jong-Do KIM; Myeong-Hoon LEE; Su-Jin LEE; Woon-Ju KANG


    Laser transformation hardening(LTH) is one of the laser surface modification processes. The surface hardening of rod-shaped carbon steel (SM45C) was performed by lathe-based laser composite processor with Gaussian-beam optical head. The LTH characteristics by dominant processes, longitudinal and depth directional hardness distributions and behaviors of phase transformation in hardened zones were examined. Especially, two concepts of circumferential speed and theoretical overlap rate were applied. When laser power increased or circumferential speed decreased, the surface hardening depth gradually increases due to the increased heat input. Moreover, the longitudinal hardness distribution particularly shows periodicity of repetitive increase and decrease, which results from tempering effect by overlap. Finally, the feasibility of laser transformation hardening is verified by using the beam with Gaussian intensity distribution.

  11. The effect of cyclic hardening on fatigue properties of modified asphalt


    The phenomenon of cyclic hardening is observed in fatigue tests of modified asphalt controlled by low strain/stress level and it is not clear how the phenomenon affects the fatigue properties of binders. The special time weep tests were performed to investigate the point. Tests results indicate that the cyclic hardening is caused by the rearrangement of molecules in binders, and it can make the inner structure of binders getting stable and increase the fatigue properties of asphalt binders. But fatigue damage occurs when fatigue tests start, no matter the phenomenon of cyclic hardening happens or not. If the controlled load is low, the effect of rearrangement of molecules on material is beyond the effect of fatigue damage so that the cyclic hardening can be observed. When the load conditions get worse, the effect of slight fatigue damages produced in hardening stage will show.

  12. A fast beam hardening correction method incorporated in a filtered back-projection based MAP algorithm

    Luo, Shouhua; Wu, Huazhen; Sun, Yi; Li, Jing; Li, Guang; Gu, Ning


    The beam hardening effect can induce strong artifacts in CT images, which result in severely deteriorated image quality with incorrect intensities (CT numbers). This paper develops an effective and efficient beam hardening correction algorithm incorporated in a filtered back-projection based maximum a posteriori (BHC-FMAP). In the proposed algorithm, the beam hardening effect is modeled and incorporated into the forward-projection of the MAP to suppress beam hardening induced artifacts, and the image update process is performed by Feldkamp–Davis–Kress method based back-projection to speed up the convergence. The proposed BHC-FMAP approach does not require information about the beam spectrum or the material properties, or any additional segmentation operation. The proposed method was qualitatively and quantitatively evaluated using both phantom and animal projection data. The experimental results demonstrate that the BHC-FMAP method can efficiently provide a good correction of beam hardening induced artefacts.

  13. Effects of different tempers on precipitation hardening of 6000 series aluminium alloys

    LIU Hong; ZHAO Gang; LIU Chun-ming; ZUO Liang


    By means of Vickers hardness, mechanical property and formability tests, the effects of different tempers on precipitation hardening of 6000 series aluminium alloys for automotive body sheets were investigated. The results indicate that the short-time pre-aging at 170 ℃ makes for subsequent artificial aging precipitation hardening. With the increase of pre-aging time, the artificial aging hardenability increases. The aging hardening rate reaches the maximum when pre-aging time is up to 10 min, and then it decreases. The short-time pre-aging at 170 ℃ benefits sheets to obtain lower strength under delivery condition and consequently to improve stamping formability of automotive body sheets. The effects of different tempers on precipitation hardening are much more obvious than those of the alloying elements. It is a good treatment schedule to perform pre-aging for 5 min at 170 ℃ right after solution treatment.

  14. Numerical analysis of drilling hole work-hardening effects in hole-drilling residual stress measurement

    Li, H.; Liu, Y. H.


    The hole-drilling strain gage method is an effective semi-destructive technique for determining residual stresses in the component. As a mechanical technique, a work-hardening layer will be formed on the surface of the hole after drilling, and affect the strain relaxation. By increasing Young's modulus of the material near the hole, the work-hardening layer is simplified as a heterogeneous annulus. As an example, two finite rectangular plates submitted to different initial stresses are treated, and the relieved strains are measured by finite element simulation. The accuracy of the measurement is estimated by comparing the simulated residual stresses with the given initial ones. The results are shown for various hardness of work-hardening layer. The influence of the relative position of the gages compared with the thickness of the work-hardening layer, and the effect of the ratio of hole diameter to work-hardening layer thickness are analyzed as well.

  15. Carbon nanotube-based coatings on titanium

    Elzbieta Dlugon; Wojciech Simka; Aneta Fraczek-Szczypta; Wiktor Niemiec; Jaroslaw Markowski; Marzena Szymanska; Marta Blazewicz


    This paper reports results of the modification of titanium surface with multiwalled carbon nanotubes (CNTs). The Ti samples were covered with CNTs via electrophoretic deposition (EPD) process. Prior to EPD process, CNTs were functionalized by chemical treatment. Mechanical, electrochemical and biological properties of CNT-covered Ti samples were studied and compared to those obtained for unmodified titanium surface. Atomic force microscopy was used to investigate the surface topography. To determine micromechanical characteristics of CNT-covered metallic samples indentation tests were conducted. Throughout electrochemical studies were performed in order to characterize the impact of the coating on the corrosion of titanium substrate. In vitro experiments were conducted using the human osteoblast NHOst cell line. CNT layers shielded titanium from corrosion gave the surface-enhanced biointegrative properties. Cells proliferated better on the modified surface in comparison to unmodified titanium. The deposited layer enhanced cell adhesion and spreading as compared to titanium sample.

  16. Identification and developmental expression of mRNAs encoding putative insect cuticle hardening hormone, bursicon in the green shore crab Carcinus maenas.

    Wilcockson, David C; Webster, Simon G


    Bursicon is the ultimate hormone in insect ecdysis, which is involved in cuticle hardening. Here we show that mRNAs encoding the heterodimeric cystine knot protein bursicon (Burs alpha, beta), are present in crustaceans, suggesting ubiquity of this hormone in arthropods. We firstly report the cloning, sequencing of mRNAs encoding subunits from the water flea, Daphnia arenata and the CNS of the crab, Carcinus maenas, in comparison with insect bursicon subunits. Expression patterns of alpha and beta burs mRNAs were examined by in-situ hybridisation (ISH) and quantitative RT-PCR. In the thoracic ganglion, burs alpha and beta mRNAs were completely colocalised in neurones expressing crustacean cardioactive peptide (CCAP). However, in the brain and eyestalk, bursicon transcripts were never observed, despite a complex expression pattern of CCAP interneurones. Patterns of expression of burs alpha and beta mRNAs were constitutive during the moult cycle of adult crabs, in stark contrast to the situation in insects. Whilst copy numbers of burs beta transcripts closely matched those of CCAP, those of burs alpha mRNA were around 3-fold higher than burs beta. This pattern was apparent during embryogenesis, where bursicon transcripts were first observed at around 50% development-the same time as first expression of CCAP mRNA. Transcript ratios (burs alpha: beta) increased during development. Our studies have shown, for the first time, that bursicon mRNAs are expressed in identified neurones in the nervous system of crustaceans. These findings will now promote further investigation into the functions of bursicon during the moult cycle and development of crustaceans.

  17. Betting Against Beta

    Frazzini, Andrea; Heje Pedersen, Lasse

    .S. equities, 20 international equity markets, Treasury bonds, corporate bonds, and futures; (2) A betting-against-beta (BAB) factor, which is long leveraged low beta assets and short high-beta assets, produces significant positive risk-adjusted returns; (3) When funding constraints tighten, the return...

  18. Titanium - ceramic restoration: How to improve the binding between titanium and ceramic

    Harry Laksono


    Full Text Available Background: Titanium alloys has been used as an alternative to nickel-chromium alloys for metal-ceramic restorations because of its good biocompatibility and mechanical properties. This indicated that it was possible to design coping according to standards established for metal-ceramics. However, titanium is chemically reacting strongly with gaseous elements which causes problems when ceramics are fused to titanium. Purpose: To provide information about improving the bonding between titanium and ceramic. Review: Titanium has two crystal modifications, the close-packed hexagonal (α structure, up to 880° C, and above this temperature the bodycentered cubic (β structure. The principal problems is the extensive dissolution of oxygen resulting in thick, oxygen-rich titanium layers called α-case that harms the bonding of ceramic to titanium and the great mismatch in the coefficient of thermal expansion of conventional ultra-low fusing ceramic. Methods have been developed for fusing ceramic to titanium like processing methods, the used of ultra-low fusing titanium ceramic, bonding agent, and protocol for ceramic bonding to titanium. Conclusion: Titanium and titanium alloys, based on their physical and chemical properties suitable for titanium-ceramic restorations, but careful selection of processing methods, ceramic materials, laboratory skill and strict protocol for ceramic bonding to titanium are necessary to improve the bonding between titanium and ceramic.Latar Belakang: Logam campur titanium telah dipakai sebagai salah satu bahan alternatif untuk logam nikel-krom pada pembuatan restorasi keramik taut logam karena mempunyai biokompatibilitas dan sifat mekanik yang baik. Hal ini menunjukkan bahwa logam titanium dapat dipakai untuk pembuatan koping logam berdasarkan standar yang dipakai untuk pembuatan restorasi keramik taut logam. Meskipun, secara kimiawi logam titanium bereaksi dengan elemen-elemen gas yang menyebabkan masalah pada perlekatan

  19. A New Construction Material-Titanium


    the Academy of Sciences of the Georgian SSR resulted in important proposals for the pro- duction of gallic acid and other preparations. AT-3 tita’ 4um...titanium with various elements, looks at phase transformation in certain alloy systems~and separateI alloys used in Industry. The articles give the...titanium alloys. Questions of the use of titanium and its alloys in various areas of the national econcmy are given. The work was written for scientists

  20. Production of titanium from ilmenite: a review

    Kohli, R.


    The general principles for beneficiation of titanium ores are reviewed and the specific processes used in individual units in various countries are discussed. This is followed by a critical evaluation of various current and potential reduction methods for the production of titanium metal from the processed concentrates. Finally, the report outlines a research program for the development of a commercially viable alternative method for the production of titanium metal.

  1. Investigation of Infiltrated and Sintered Titanium Carbide


    taneive investigations in this field during the ’time preceding this contract, and concentrated their effort® On titanium carbide as the’ refractospy...component • The Basic work of this investigation consisted of? X, KpälfiCÄVtloh and refinement of cOmätrcial grades of titanium carbide hj...facilitate a comparison between the different methods» an investigation was then carried out with composite bodies* consisting of titanium carbide asd

  2. Brazing titanium structures. Final report

    Pressly, H.B.


    A vacuum furnace brazing process using Ag-5A1-0.5Mn brazing alloy has been developed for joining titanium alloy Ti-6Al-4V structures. Lap-shear strengths of the braze joints and the effects of the brazing thermal cycle on the tensile and bending properties of mill-annealed Ti-6Al-4V alloy sheet are reported. Nondestructive test methods were evaluated for detecting defects in these braze joints.

  3. The use of titanium alloys for dynamic risers: a literature review

    Torster, F.; Kocak, M.; Santos, J.F. dos [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Werkstofforschung; Hutt, G. [Stolt Comex Seaway Ltd., Aberdeen, (Scotland)


    The main topic of this short literature review is to describe the material related aspects concerning the production and purpose of flexible titanium risers for offshore oil and gas production. Metallurgy and alloying of titanium are briefly introduced. The review concentrates on the materials properties that are relevant for the intended use in marine environment. The focus is put on {alpha}+{beta} Ti-alloys, because earlier investigations have shown that this alloy family is the most suitable one for this purpose. Further topics which are taken into account are welding processes for titanium, weld properties and aspects of the associated weld defects as well. This literature review has been carried out at GKSS-Forschungszentrum Geesthacht GmbH within the framework of the project `Titanium Risers for Deepwater Developments (contract nr. OG/175/95), supported by the THERMIE-JOULE Programme of the European Commission. The project consortium is formed by Stolt Comex Seaway Ltd. (UK), Seaflex AS (Norway) and GKSS (Germany). (orig.) [Deutsch] Die vorliegende kurze Literaturrecherche befasst sich vorrangig mit den materialbezogenen Aspekten der Produktion und des Einsatzes von flexiblen `Risern` aus Titanlegierungen fuer die Oel- und Gasfoerderung auf See. Die Metallurgie und das Legieren von Titan werden kurz vorgestellt. Die Recherche konzentriert sich im weiteren auf die Materialeigenschaften, die fuer den vorgesehenen Einsatz in mariner Umgebung von besonderer Bedeutung sind. In erster Linie wird dabei auf {alpha}+{beta}-Titanlegierungen eingegangen, da vorausgegangene Untersuchungen gezeigt haben, dass diese Legierungsfamilie die guenstigsten Eigenschaften fuer das vorgesehene Einsatzgebiet aufweist. Im weiteren werden die Schweissprozesse, die bei Titanlegierungen eingesetzt werden, vorgestellt und die Eigenschaften und moeglichen Schweissfehler der hergestellten Schweissverbindungen gegenuebergestellt. Diese Literaturrecherche wurde im GKSS-Forschungszentrum im

  4. Cooling Curve's Effect on Hardening Behavior of Steel

    Kazuto Fukuhara; Shigeru Asada; Yoshihiro Tomita; Syusaku Maeda


    Quenching Oils are comprised mostly of mineral oil as major component, but mineral oil alone result in lower cooling performance. Therefore, various additives are formulated as required for each particular case. Cooling curves of mineral oil as determined by JIS method can be divided into three stages, vapor film stage, boiling stage and convection stage. And there are many types of additives used for quenching oil, one effective to shorten vapor film stage and another to shift boiling stage toward lower temperature side. As rapid quenching required temperature range for particular steel varies pending on its shape of CCT curve(1), it is possible to provide higher quench hardening performance using quenching oil formulated of adequate additives.

  5. Water management in hardening Maytenus ilicifolia (Schrad. Planch. seedlings

    João Alexandre Lopes Dranski


    Full Text Available This study evaluated the effects of seedling height and irrigation management on M. ilicilofia seedlings. The experiment used a completely randomized design in a 2 x 3 factorial arrangement. Seedlings of two height classes (greater than or less than 18.0 cm were subjected to three irrigation regimes (daily irrigation, irrigation every other day, and gradual reduction of irrigation. After eight weeks, the morphophysiological and performance attributes of the seedlings were quantified. Gradual reduction of irrigation promoted the highest rate of net carbon assimilation. Irrigating every other day resulted in greater secondary growth rate, biomass accumulation in the shoot and root tissues, and lower electrolyte leakage rate. After planting, these treatments maintained higher leaf relative water content (RWC. RWC in seedlings smaller than 18 cm was significantly higher until the third week after planting. Therefore, larger seedlings submitted to hardening by gradually reducing irrigation improves seedling quality.


    ZHANG Taohong; YU Gang; WANG Jianlun; LIU Xiangyang


    A new method of collision-free path plan integrated in virtual processing is developed to improve the efficiency of laser surface hardening on dies. The path plan is based on the premise of no collision and the optimization object is the shortest path. The optimization model of collision-free path is built from traveling salesman problem (TSP). Collision-free path between two machining points is calculated in configuration space (C-Space). Ant colony optimization (ACO) algorithm is applied to TSP of all the machining points to find the shortest path, which is simulated in virtual environment set up by IGRIP software. Virtual machining time, no-collision report, etc, are put out after the simulation. An example on autobody die is processed in the virtual platform, the simulation results display that ACO has perfect optimization effect, and the method of virtual processing with integration of collision-free optimal path is practical.

  7. Advances in positron studies of age hardening in light alloys

    Somoza, A. [IFIMAT, UNCentro and CICPBA, Pinto, Tandil (Argentina); Dupasquier, A.; Ferragut, R. [LNESS and CNISM, Politecnico di Milano, Como (Italy)


    The extensive experimental work on age hardening of Al- and Mg-based alloys, performed by the associated groups at IFIMAT (UNCentro, Argentina) and at LNESS (Politecnico di Milano, Italy) in recent years, is discussed here in a comprehensive way, with attention to experimental procedures and to results of general validity. For Al-based alloys, the established knowledge regarding the different action of Zn, Cu, Mg and Ag in the formation of vacancy-solute clusters is presented. For Mg-based alloys, the limits of positron annihilation spectroscopy are discussed on the basis of experience in progress. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Identifying Vulnerabilities and Hardening Attack Graphs for Networked Systems

    Saha, Sudip; Vullinati, Anil K.; Halappanavar, Mahantesh; Chatterjee, Samrat


    We investigate efficient security control methods for protecting against vulnerabilities in networked systems. A large number of interdependent vulnerabilities typically exist in the computing nodes of a cyber-system; as vulnerabilities get exploited, starting from low level ones, they open up the doors to more critical vulnerabilities. These cannot be understood just by a topological analysis of the network, and we use the attack graph abstraction of Dewri et al. to study these problems. In contrast to earlier approaches based on heuristics and evolutionary algorithms, we study rigorous methods for quantifying the inherent vulnerability and hardening cost for the system. We develop algorithms with provable approximation guarantees, and evaluate them for real and synthetic attack graphs.

  9. Hardening by annealing and softening by deformation in nanostructured metals

    Huang, X.; Hansen, N.; Tsuji, N.


    -dislocation and dislocation-interface reactions, such that heat treatment reduces the generation and interaction of dislocations, leading to an increase in strength and a reduction in ductility. A subsequent deformation step may restore the dislocation structure and facilitate the yielding process when the metal is stressed......We observe that a nanostructured metal can be hardened by annealing and softened when subsequently deformed, which is in contrast to the typical behavior of a metal. Microstructural investigation points to an effect of the structural scale on fundamental mechanisms of dislocation....... As a consequence, the strength decreases and the ductility increases. These observations suggest that for materials such as the nanostructured aluminum studied here, deformation should be used as an optimizing procedure instead of annealing....

  10. Thermal Hardening: A New Seed Vigor Enhancement Tool in Rice

    Muhammad FAROOQ; S. M. A. BASRA; Nazir AHMAD; K. HAFEEZ


    In a laboratory study, indica and japonica rice (Oryza sativa L.) seeds were exposed to thermal hardening (heating followed by chilling followed by heating; chilling followed by heating followed by chilling; heating followed by chilling or chilling followed by heating). In indica rice, heating followed by chilling followed by heating resulted in decreased mean germination time, time to start germination, electrical conductivity of seed leachates, and time to 50% germination, as well as increased germination index, energy of germination, radicle and plumule length, root length, root/shoot ratio, root fresh and dry weight, radicle and plumule growth rate, and shoot fresh weight. In japonica rice, chilling followed by heating followed by chilling performed better than all other treatments, including control.

  11. Titanium alloys Russian aircraft and aerospace applications

    Moiseyev, Valentin N


    This text offers previously elusive information on state-of-the-art Russian metallurgic technology of titanium alloys. It details their physical, mechanical, and technological properties, as well as treatments and applications in various branches of modern industry, particularly aircraft and aerospace construction. Titanium Alloys: Russian Aircraft and Aerospace Applications addresses all facets of titanium alloys in aerospace and aviation technology, including specific applications, fundamentals, composition, and properties of commercial alloys. It is useful for all students and researchers interested in the investigation and applications of titanium.

  12. 2005 Xi'an International Titanium Conference


    @@ First Circular Call for Papers In the 98' Xi'an International Titanium Conference (XITC'98), more than 300 representatives of the research and industry circles from 12 countries were gathered in Xi'an to exchange the new progress on titanium R&D and industrialization. XITC'98played an important role in promoting titanium R&D for the world, especially for China. In order to let the people engaged in titanium industry know more Chinese and the world titanium industry, promote the exchange and cooperation of the world titanium circle, we decide to hold the 2005 Xi'an International titanium Conference (XITC'05), which will be held on October 16~19, 2005 in Xi'an, China. The conference will provide a forum on the exchange and discussion of new ideas and achievements related to the aspects of titanium technology and industry in recent years. At the same time, the 12th China National Conference on Titanium will be held on October 19~23, 2005 in the same place after XITC'05.

  13. Appcelerator Titanium patterns and best practices

    Pollentine, Boydlee


    The book takes a step-by-step approach to help you understand CommonJS and Titanium architecture patterns, with easy to follow samples and plenty of in-depth explanations If you're an existing Titanium developer or perhaps a new developer looking to start off your Titanium applications "the right way", then this book is for you. With easy to follow examples and a full step-by-step account of architecting a sample application using CommonJS and MVC, along with chapters on new features such as ACS, you'll be implementing enterprise grade Titanium solutions in no time. You should have some JavaSc

  14. Titanium Matrix Composite Pressure Vessel Project

    National Aeronautics and Space Administration — For over 15 years, FMW Composite Systems has developed Metal Matrix Composite manufacturing methodologies for fabricating silicon-carbide-fiber-reinforced titanium...


    Kazimierz Zaleski


    Full Text Available This study presents the results of tests on impact of vibratory and rotational shot peening of the Ti6A12Mo2Cr titanium alloy onto the processed object surface roughness and surface layer microhardness. The external surfaces of ring-shaped samples were shot peened. The preceding process consisted of turning with a cubic boron nitride blade knife. Steel beads, having a diameter of 6 mm, were used as a processing medium. The variable parameters of shot peening were vibrator amplitude and shot peening time. The range of recommended technological parameters for vibratory and rotational shot peening was determined. As a result of shot peening, the surface roughness could be reduced by approximately 4 times and the surface layer could be hardened to the depth of approximately 0.4 mm.

  16. Springback prediction of titanium tube bending considering Bauschinger effect and Young's modulus variation

    Ma, J.; Yang, H.; Li, H.; Tao, Z. J.; Li, G. J.


    High strength titanium bent tubes present promising usages in advanced aircraft and spacecraft to achieve lightweight and improve overall performance. However, the high ratio of yield strength to Young's modulus results in significant springback in bending, which limits their forming accuracy. In this work, the Bauschinger effect and nonlinear unloading behavior of high strength Ti-3Al-2.5V tube are experimentally investigated. Then, to describe such behaviors, the Yoshida-Uemori (Y-U) two-surface hardening model and Chord unloading model are introduced into the elastoplastic constitutive framework and numerically implemented. Taking rotary draw (RDB) bending as a case, the springback angles are predicted and analyzed by comparison with the experimental results.

  17. Low-temperature tolerance and cold hardening of cacti

    Nobel, P.S.


    Reduced uptake by the chlorenchyma cells of cacti of a stain (neutral red) was used as an indicator of low-temperature damage resulting from cooling stems in the laboratory. Necrosis set in a few degrees below the temperature at which the fraction of cells accumulating stain was reduced by 50%. Coryphantha vivipara, Opuntia polyacantha, and Pediocactus simpsonii, which range to over 300 m altitude in southern Wyoming, were quite cold tolerant. Relationships among tissue cold sensitivity, morphological features which protect the stems from low temperatures, and the occurrence of species in progressively colder regions were investigated. Differences in tissue cold sensitivity accounted for the approx. = 600 m higher elevational limit of Coryphantha vivipara var. rosea compared to the morphologically similar var. deserti in southern Nevada. In contrast, morphological differences alone could adequately explain the relative northern limits of the columnar cacti Carnegiea gigantea vs Stenocereus gummosus and the barrel cacti Ferocactus acanthodes vs. F. wislizenii in the southwestern United States, as previously indicated using a computer model. Cold hardening in response to decreasing day/night air temperatures was observed for 10 species. A decrease from 50/sup 0//40/sup 0/ to 10/sup 0//0/sup 0/ lowered by 4/sup 0/ the temperature at which the fraction of the chlorenchyma cells taking up stain was reduced 50% for both D. rhodacantha and T. candicans, with a half-time for the shift of approx. = 3 d. The tolerance of subzero temperatures and the ability to cold harden allow cacti to range into regions with considerable wintertime freezing.

  18. [Hardened anodized aluminum as a replacement material for bracket manufacture].

    Fischer-Brandies, H; Bönhoff, M


    Attention has been repeatedly drawn to the problem of corrosion and the risk of allergic reaction to nickel resulting from the use of stainless steel brackets. In the search for a suitable alternative, manufacturers have turned to thin coating technology using hardened anodized aluminium. Applying resistance to corrosion and abrasion as the criteria to be met, they have selected aluminium alloy type 6082 as the material of choice. Purpose of this study is to examine the physical suitability of this material. Using the above noted alloy, 60 prototype brackets were made with a hardened anodized surface. They were then subjected to the following 3 stress tests: first an abrasion test using a tooth polishing machine, second, a deformation test using a device designed to simulate torque movement, and, third, a corrosion test. The effects on the brackets resulting from the three types of stress were evaluated by light microscopy. A quantitative analysis of the corrosion test was performed by ICP spectrometry. The control group consisted of conventional stainless steel brackets. The light microscopic analysis revealed no evidence of surface damage or signs of deformation in the prototype brackets. The steel brackets, on the other hand, showed clear signs of wear and corrosion. The quantitative analysis of the corrosion solution revealed metallic ion wear of 1.75 ng x mm-2 x h-1 for the prototypes subjected to abrasion. The steel brackets showed at a factor of around 104.6 metallic ion wear of 183 ng x mm-2 x h-1. In addition to this, no Ni ions were found in the corrosion solution of the prototype brackets.(ABSTRACT TRUNCATED AT 250 WORDS)

  19. Characterization and hardening of concrete with ultrasonic testing.

    del Río, L M; Jiménez, A; López, F; Rosa, F J; Rufo, M M; Paniagua, J M


    In this study, we describe a technique which can be used to characterize some relevant properties of 26 cylindrical samples (15 x 30 cm2) of concrete. The characterization has been performed, according to Spanish regulations in force, by some destructive and ultrasound-based techniques using frequencies of 40 kHz. Samples were manufactured using different water/cement ratios (w/c), ranging from 0.48 to 0.80, in order to simulate different values of compressive strength at each sample. We have correlated the propagation velocity v of ultrasonic waves through the samples to compressive strength R values. As some other authors remark, there exists an exponential relationship between the two above parameters. We have found that a highly linear relationship is present between R and w/c concentration at the samples. Nevertheless, when the same linear model is adopted to describe the relationship between v and w/c, the value of r decreases significantly. Thus, we have performed a multiple regression analysis which takes into account the impact of different concrete constituents (water, cement, sand, etc.) on ultrasound propagation speed. One of the most relevant practical issues addressed in our study is the estimation of the hardening curve of concrete, which can be used to quantify the viability of applying the proposed method in a real scenario. Subsequently, we also show a detailed analysis of the temporal evolution of v and R through 61 days, beginning at the date where the samples were manufactured. After analyzing both parameters separately, a double reciprocal relationship is deduced. Using the above parameters, we develop an NDE-based model which can be used to estimate hardening time of concrete samples.

  20. Calcium phosphate cements: study of the beta-tricalcium phosphate--monocalcium phosphate system.

    Mirtchi, A A; Lemaitre, J; Terao, N


    The possibility of making cements based on beta-tricalcium phosphate (beta-TCP), a promising bone graft material, was investigated. Upon admixture with water, beta-TCP/monocalcium phosphate monohydrate (MCPM) mixtures were found to set and harden like conventional hydraulic cements. Beta-TCP powders with larger particle size, obtained by sintering at higher temperatures, increased the ultimate strength of the cement. Results show that setting occurs after dissolution of MCPM, as a result of the precipitation of dicalcium phosphate dihydrate (DCPD) in the paste. The ultimate tensile strength of the hardened cement is proportional to the amount of DCPD formed. Upon ageing above 40 degrees C, DCPD transforms progressively into anhydrous dicalcium phosphate (DCP), thereby decreasing the strength. Ageing of the pastes in 100% r.h. results in a decay of the mechanical properties. This can be ascribed to an intergranular dissolution of the beta-TCP aggregates as a result of the pH lowering brought about by the MCPM to DCPD conversion.

  1. Forward-Looking Betas

    Christoffersen, Peter; Jacobs, Kris; Vainberg, Gregory

    Few issues are more important for finance practice than the computation of market betas. Existing approaches compute market betas using historical data. While these approaches differ in terms of statistical sophistication and the modeling of the time-variation in the betas, they are all backward......-looking. This paper introduces a radically different approach to estimating market betas. Using the tools in Bakshi and Madan (2000) and Bakshi, Kapadia and Madan (2003) we employ the information embedded in the prices of individual stock options and index options to compute our forward-looking market beta...


    A. I. Mihluk


    Full Text Available The new approach for technology of volumetric – superficial hardening of gear details of the back axle made of steel lowered harden ability is offered. This approach consisting in formation of intense – hardened condition on all surface of a detail.

  3. Micro-toughened titanium-based intermetallics for high-temperature service. CRADA final report

    Sikka, V.K.; Liu, C.T.; Blue, C.A. [and others


    This Cooperative Research and Development Agreement (CRADA) report deals with the composition development, processing parameter development, microstructural evaluation, and mechanical properties development of the {beta} TiAl alloys. Two series of alloy compositions were identified. The first series consisted of four alloys, and the second series consisted of three alloys. The powders were packed in titanium cans, evacuated, and sealed. The titanium cans were hot extruded at 1150, 1250, and 1400{degrees}C to an area reduction ratio of 16:1. The extruded bars were heat treated between 800 and 1320{degrees}C, and their microstructure characterized in the extended and heat-treated condition by optical, scanning, and transmission electron microscopy (TEM). The microstructural features such as colony size, width of colony boundary {beta} layer, interlamellar spacing, {alpha}{sub 2}-{alpha}{sub 2} spacing, {beta}lamellar width, and {alpha}{sub 2}-{beta} layer ratio were quantified. Tensile bars were prepared from the extruded bars by electrodischarge machining followed by grinding. Tensile tests were conducted from room temperature to 1000{degrees}C. Three-point-bend tests were used to measure the fracture toughness at both room temperature and 800{degrees}C. The effect of long-term annealing at 800 and 1000{degrees}C on one of the alloys was measured at room temperature. Tensile properties of the alloys of this study were compared with the data reported in literature.

  4. 一种生物医用近β钛合金在人工唾液中粗糙度变化的研究%An experimental study on variation of the surface roughness of one type of near beta biomedical titanium alloy in artificial saliva

    刘晓晨; 李晓红


    Objective The Study on variation of the surface roughness of a new type of titanium alloy in simulated oral environment surface,and given clinical guidance for patients who have received titanium implant therapy or wear denture. Methods Titanium chips are prepared and divided into eight groups randomly.Surface roughness of each specimen were examined before the treatment,on the 30th day and on the 60th day after the treatment. Results The surface roughness of the brushing group was more evident than that of the non-brushing group (P0.05).PH had a significant interactive effect with fluoride ionic concentration (P< 0.05). Conclusion pH,fluoride ionic concentration,tooth brushing and experimental session all have an effect on the degree of corrosion.%目的:研究一种新型钛合金在模拟口腔环境中的表面粗糙度改变,为口腔内存在钛合金种植体或戴用钛合金义齿的患者给予临床指导.方法:将制备好的钛合金试件随机分为8组.每组试件于处理前,以及处理后1个月、2个月时分别测量表面粗糙度,应用SPSS统计软件分析所得结果.结果:刷洗组试件相对不刷洗组试件表面粗糙度增大,具有统计学意义(P<0.01);使用含氟牙膏组的粗糙度增大值略大于不含氟牙膏组,但两组粗糙度的增大值无统计学意义(P>0.05);通过对pH值和氟离子浓度两个因素的交互效应的统计学分析,提示两因素之间存在交互作用(P<0.05),具有统计学意义.结论:钛合金试件的腐蚀程度主要与实验周期、是否刷洗,以及氟离子浓度和pH值的交互作用有关.

  5. 一种生物医用近β钛合金在人工唾液中表面色泽变化的研究%An experimental study on variation of the surface color of one type of near beta biomedical titanium alloy in artificial saliva

    刘晓晨; 李晓红; 孙东涛


    目的:研究一种新型钛合金在模拟口腔环境中的表面色泽的改变,为口腔内存在钛合金种植体或戴用钛合金义齿的患者给予临床指导。方法将制备好的钛合金试件随机分为8组。每组试件于处理前以及处理后,分别测量色彩值CIE L*a*b*,应用SPSS 统计软件分析所得结果。结果刷洗组试件相对不刷洗组试件表面色泽改变增大,具有统计学意义(P<0.01);使用含氟牙膏组的表面色泽改变略大于不含氟牙膏组,但两组改变值无统计学意义(P >0.05);通过对pH 值和氟离子浓度两个因素的交互效应的统计学分析,提示两因素之间存在交互作用(P <0.05),具有统计学意义。结论近β钛合金的腐蚀程度主要与是否刷洗,以及模拟口腔环境中氟离子浓度和pH 值的交互作用有关。%Objective To study the variation of the surface color of a new type of titanium alloy in simulated oral environment sur-face,and to provide clinical guidance for patients who have received titanium implant therapy or wear denture. Methods Titanium chips were prepared and divided into eight groups randomly. CIE L*a*b* of each specimen was examined by SPSS software before and after treatment. Results The surface color of the brushing group was more evident than that of the non-brushing group (P 0. 05). pH value had a significant interactive effect with fluoride ionic concentration (P < 0. 05). Conclusions pH,fluoride ionic concentration,and tooth brushing all have an effect on the degree of corrosion.

  6. Solid State Joining of Dissimilar Titanium Alloys

    Morton, Todd W.

    Solid state joining of titanium via friction stir welding and diffusion bonding have emerged as enablers of efficient monolithic structural designs by the eliminations fasteners for the aerospace industry. As design complexity and service demands increase, the need for joints of dissimilar alloys has emerged. Complex thermomechanical conditions in friction stir weld joints and high temperature deformation behavior differences between alloys used in dissimilar joints gives rise to a highly variable flow pattern within a stir zone. Experiments performed welding Ti-6Al-4V to beta21S show that mechanical intermixing of the two alloys is the primary mechanism for the generation of the localized chemistry and microstructure, the magnitude of which can be directly related to pin rotation and travel speed weld parameters. Mechanical mixing of the two alloys is heavily influenced by strain rate softening phenomena, and can be used to manipulate weld nugget structure by switching which alloy is subjected to the advancing side of the pin. Turbulent mixing of a weld nugget and a significant reduction in defects and weld forces are observed when the beta21S is put on the advancing side of the weld where higher strain rates are present. Chemical diffusion driven by the heat of weld parameters is characterized using energy dispersive x-ray spectroscopy (EDS) and is shown to be a secondary process responsible for generating short-range chemical gradients that lead to a gradient of alpha particle structures. Diffusion calculations are inconsistent with an assumption of steady-state diffusion and show that material interfaces in the weld nugget evolve through the break-down of turbulent interface features generated by material flows. A high degree of recrystallization is seen throughout the welds, with unique, hybrid chemistry grains that are generated at material interfaces in the weld nugget that help to unify the crystal structure of dissimilar alloys. The degree of

  7. The role of whole blood in thrombin generation in contact with various titanium surfaces.

    Thor, Andreas; Rasmusson, Lars; Wennerberg, Ann; Thomsen, Peter; Hirsch, Jan-Michael; Nilsson, Bo; Hong, Jaan


    Understanding of the thrombotic response (activation of the intrinsic coagulation system followed by platelet activation) from blood components upon contact with a titanium dental implant is important and not fully understood. The aims of this study were to evaluate: (1) the thrombogenic response of whole blood, platelet-rich plasma (PRP) and platelet-poor plasma (PPP) in contact with a highly thrombogenic surface as titanium, (2) the thrombogenic response of clinically used surfaces as hydroxyapatite (HA), machined titanium (mTi), TiO2 grit-blasted titanium (TiOB) and fluoride ion-modified grit-blasted titanium (TiOB-F). An in vitro slide chamber model, furnished with heparin, was used in which whole blood, PRP or PPP came in contact with slides of the test surfaces. After incubation (60 min rotation at 22 rpm in a 37 degrees C water bath), blood/plasma was mixed with EDTA or citrate, further centrifuged at +4 degrees C (2200 g at 10 min). Finally, plasma was collected pending analysis. Whole blood in contact with Ti alloy resulted in the binding of platelets to the material surface and in the generation of thrombin-antithrombin (TAT) complexes. With whole blood TAT levels increased 1000-fold compared with PRP and PPP, in which both almost no increase of TAT could be detected. In addition, the platelet activation showed a similar pattern with a 15-fold higher release of beta-TG in whole blood. In the in vitro chamber model with the clinically relevant materials, the fluoride-modified surface (TiOB-F) showed pronounced TAT generation compared with TiOB, mTi and HA. Similar results were achieved for platelet consumption and activation markers of the intrinsic coagulation system. Taken together these results implicate first that whole blood is necessary for sufficient thrombin generation and platelet activation during placement of implants. Second, a fluoride ion modification seems to augment the thrombogenic properties of titanium.

  8. Effects of shot peening and laser remelting on oxygen-permeation treatment of titanium alloy

    MA Hong-yan; WANG Mao-cai; WEI Zheng; XIN Gong-chun


    The influence of surface pre-treatments, shot-peening (SP) and laser remelting (LR), on oxygen permeation behaviors of titanium alloy TC11 was investigated. Optical microscope, SEM with EDAX, XRD, and microhardness tester were employed to characterize the microstructure, composition and hardness of this alloy. The results show that the surface roughness is increased by shot-peening, and the microstructure with fine-grain can be obtained by LR pre-treatment. The pre-treated samples were oxygen-permeated at (810± 10) ℃ for 10 h in atmospheric air. The outer layer consists essentially of TiO2, trace Ti2 N, Ti3Al and Ti3AlN for the SP pre-treatment and thin oxygen solution layer is found in the subsurface layer. As for LR pre-treatment, the outer layer consists mainly of TiO2 and small amounts of TiO, and the inner layer consists of alpha crystals, rich in interstitial atoms. Samples by LR pre-treatment has thicker hardened layer with higher hardness values in comparison with SP pre-treated ones.The boost diffusion of oxygen and hardening mechanisms were discussed based on the experimental results.

  9. Study of stress relief cracking in titanium stabilized austenitic stainless steel; Etude de la fissuration differee par relaxation d'un acier inoxydable austenitique stabilise au titane

    Chabaud-Reytier, M


    The heat affected zone (HAZ) of titanium stabilised austenitic stainless steel welds (AISI 321) may exhibit a serious form of intercrystalline cracking during service at high temperature. This type of cracking, called 'stress relief cracking', is known to be due to work hardening but also to ageing: a fine and abundant intragranular Ti(C,N) precipitation appears near the fusion line and modifies the mechanical behaviour of the HAZ. This study aims to better know the accused mechanism and to succeed in estimating the risk of such cracking in welded junctions of 321 stainless steel. To analyse this embrittlement mechanism, and to assess the lifetime of real components, different HAZ are simulated by heat treatments applied to the base material which is submitted to various cold rolling and ageing conditions in order to reproduce the HAZ microstructure. Then, we study the effects of work hardening and ageing on the titanium carbide precipitation, on the mechanical (tensile and creep) behaviour of the resulting material and on its stress relief cracking sensitivity. It is shown that work hardening is the main parameter of the mechanism and that ageing do not favour crack initiation although it leads to titanium carbide precipitation. The role of this precipitation is also discussed. Moreover, a creep damage model is identified by a local approach to fracture. Materials sensitive to stress relief cracking are selected. Then, creep tests are carried out on notched bars in order to quantify the intergranular damage of these different materials; afterwards, these measurements are combined with calculated mechanical fields. Finally, it is shown that the model gives good results to assess crack initiation for a compact tension (CT) specimen during relaxation tests, as well as for a notched tubular specimen tested at 600 deg. C under a steady torque. (author)

  10. Development of Bake Hardening Effect by Plastic Deformation and Annealing Conditions

    Kvačkaj, T.


    Full Text Available The paper deals with the classification of steel sheets for automotives industry on the basis of strength and structural characteristics. Experimental works were aimed to obtain the best possible strengthening parameters as well as work hardening and solid solution ferrite hardening, which are the result of thermal activation of interstitial carbon atoms during paint-baking of auto body. Hardening process coming from interstitial atoms is realized as two-step process. The first step is BH (bake hardening effect achieved by interaction of interstitial atoms with dislocations. The Cottrels atmosphere is obtained. The second step of BH effect is to produced the hardening from precipitation of the carbon atoms in e-carbides, or formation of Fe32C4 carbides. WH (work hardening effect is obtained as dislocation hardening from plastic deformations during sheet deep drawing. Experimental works were aimed at as to achieve such plastic material properties after cold rolling, annealing and skin-pass rolling, which would be able to classify the material ZStE220BH into the drawing categories at the level of DQ – DDQ. As resulting from the experimental results, the optimal treatment conditions for the maximal sum (WH+BH = 86 MPa are as follows: total cold rolling deformation ecold = 65 %, annealing temperature Tanneal. = 700 °C.

  11. Microstructural evolution and mechanical behaviour of surface hardened low carbon hot rolled steel

    Tewary, N.K. [Department of Metallurgy and Materials Engineering, Bengal Engineering and Science University, Shibpur, Howrah 711103 (India); Syed, B. [R and D Division, Tata Steel Limited, Jamshedpur 831007 (India); Ghosh, S.K., E-mail: [Department of Metallurgy and Materials Engineering, Bengal Engineering and Science University, Shibpur, Howrah 711103 (India); Kundu, S. [R and D Division, Tata Steel Limited, Jamshedpur 831007 (India); Shariff, S.M.; Padmanabham, G. [Centre for Laser Processing, ARCI-Hyderabad, Balapur PO, AP 500005 (India)


    Surface hardening of low carbon hot rolled C–Mn steel has been successfully performed by high power diode laser with an achievable case depth of about 300 μm. The laser treated samples have been characterised using optical microscope, scanning electron microscope, transmission electron microscope, and X-ray diffraction techniques. Higher hardness level is achieved in laser surface hardened zone (≈300 HV) than in the base alloy region (≈140 HV). The variation in hardness as a function of distance across the laser tracks is observed during multi-track laser hardening. Laser hardened steel sheets show enhanced mechanical strength (YS: 383–443 MPa, UTS: 476–506 MPa) with the lowering of percentage total elongation (23–28%) compared to the base alloy (YS: 351 MPa, UTS: 450 MPa and total elongation is 32%). Strain hardening exponent (‘n’) has been evaluated from true tensile stress–strain diagram and it shows a similar nature for both base alloy and laser treated steels. The microstructure in the base alloy region consists of a mixture of ferrite and pearlite, whereas predominantly lath martensite is present in the laser hardened surface layer. The improvement of mechanical strength is discussed in terms of the formation of this hardened layer on the surface.

  12. [Experimental research on porcelain fused to the surface of pure titanium and titanium alloys].

    Wang, D; Ai, S; Xu, J


    Titanium material has been widely used in prosthodontics since the end of 1980s. However, the research on porcelain fused to the surfaces of titanium material was quite few. This article introduced the technological process of low-fusing dental porcelain--Ceratin fused to pure titanium and titanium alloys. The values of the bond strength of Ceratin and titanium substrates were obtained by shearing test with INSTRON Model-1185. The average value of the shearing strength between TA2 and Ceratin was 31. 01MPa. The corresponding value between TC4 and Ceratin was 33.73MPa. The interface between Ceratin and titanium substrate was observed with scanning electron microscope (SEM). The results of this research proposed that it is hopeful that Ceratin is used as special procelain with titanium material.


    S. S. Samotugin


    Full Text Available Crane wheels and rails are subjected to intensive wear in the process of operation. Therefore, improvement of these components’ performance can be considered a task of high importance. A promising direction in this regard is surface treatment by highly concentrated energy flows such as laser beams or plasma jets. This thesis suggests that the use of gradient plasma surface treatment can improve the performance of crane rails. A research was conducted, according to which hardened zones were deposited on crane rails under different treatment modes. Microhardness was measured both at the surface and in depth using custom-made microsections. The article includes the results of study of plasma surface hardening effects on wear resistance of crane rails. Change of plasma surface treatment parameters (current, plasma torch movement speed, argon gas flow rate allows for desired steel hardness and structure, while the choice of optimal location for hardened zones makes it possible to significantly improve wear resistance and crack resistance. As a result of plasma surface hardening, the fine-grained martensite structure is obtained with mainly lamellar morphology and higher hardness rate compared toinduction hardening or overlaying. Wear test of carbon steels revealed that plasma surfacing reduces abrasive wear rate compared to the irinitial state by 2 to 3 times. Enough sharp boundary between hardened and non-hardened portions has a positive effect on the performance of parts under dynamic loads, contributing to the inhibition of cracks during the transition from solid to a soft metal. For carbon and low alloy rail steels, the properties achieved by plasma surface hardening can effectively replace induction hardening or overlaying.The mode range for plasma surface treatment that allow sobtaining a surface layer with certain operating properties has been determined.

  14. Work Hardening Behavior of 1020 Steel During Cold-Beating Simulation

    CUI, Fengkui; LING, Yuanfei; XUE, Jinxue; LIU, Jia; LIU, Yuhui; LI, Yan


    The present research of cold-beating formation mainly focused on roller design and manufacture, kinematics, constitutive relation, metal flow law, thermo-mechanical coupling, surface micro-topography and microstructure evolution. However, the research on surface quality and performance of workpieces in the process of cold-beating is rare. Cold-beating simulation experiment of 1020 steel is conducted at room temperature and strain rates ranging from 2000 to 4000 s-1 base on the law of plastic forming. According to the experimental data, the model of strain hardening of 1020 steel is established, Scanning Electron Microscopy(SEM) is conducted, the mechanism of the work hardening of 1020 steel is clarified by analyzing microstructure variation of 1020 steel. It is found that the strain rate hardening effect of 1020 steel is stronger than the softening effect induced by increasing temperatures, the process of simulation cold-beating cause the grain shape of 1020 steel significant change and microstructure elongate significantly to form a fibrous tissue parallel to the direction of deformation, the higher strain rate, the more obvious grain refinement and the more hardening effect. Additionally, the change law of the work hardening rate is investigated, the relationship between dislocation density and strain, the relationship between work hardening rate and dislocation density is obtained. Results show that the change trend of the work hardening rate of 1020 steel is divided into two stages, the work hardening rate decreases dramatically in the first stage and slowly decreases in the second stage, finally tending toward zero. Dislocation density increases with increasing strain and strain rate, work hardening rate decreases with increasing dislocation density. The research results provide the basis for solving the problem of improving the surface quality and performance of workpieces under cold-beating formation of 1020 steel.

  15. Effect of dry heat and steam sterilization on load-deflection characteristics of β-titanium wires: An in vitro study

    Shiva Alavi


    Conclusion: It appears dry heat sterilization increases stiffness of RES, BETA, CNA and HONE but autoclave sterilization did not have any effect on load-deflection characteristics of most of the β-titanium wires tested, indicating that clinicians who want to provide maximum safety for their patients can autoclave TMAL, RES and CNA before applying them.

  16. Titanium Carbide Bipolar Plate for Electrochemical Devices

    LaConti, Anthony B.; Griffith, Arthur E.; Cropley, Cecelia C.; Kosek, John A.


    Titanium carbide comprises a corrosion resistant, electrically conductive, non-porous bipolar plate for use in an electrochemical device. The process involves blending titanium carbide powder with a suitable binder material, and molding the mixture, at an elevated temperature and pressure.

  17. Durability of polyimide to titanium bonds

    Akram, M.; Jansen, K.M.B.; Bhowmik, S.; Ernst, L.J.


    Titanium and its alloys are usually bonded together using a high temperature resistant polyimide or epoxy adhesives. Such adhesives can withstand temperatures from 200°C to300°C. Earlier research work indicates that Surface modification of titanium with mechanical treatment and atmospheric pressure

  18. Titanium tetrachloride burns to the eye.

    Chitkara, D K; McNeela, B. J.


    We present eight cases of chemical burns of the eyes from titanium tetrachloride, an acidic corrosive liquid. However it causes severe chemical burns which have a protracted course and features more akin to severe alkali burns. Injuries related to titanium tetrachloride should be treated seriously and accordingly appropriate management is suggested.

  19. Wettability studies of topologically distinct titanium surfaces.

    Kulkarni, Mukta; Patil-Sen, Yogita; Junkar, Ita; Kulkarni, Chandrashekhar V; Lorenzetti, Martina; Iglič, Aleš


    Biomedical implants made of titanium-based materials are expected to have certain essential features including high bone-to-implant contact and optimum osteointegration, which are often influenced by the surface topography and physicochemical properties of titanium surfaces. The surface structure in the nanoscale regime is presumed to alter/facilitate the protein binding, cell adhesion and proliferation, thereby reducing post-operative complications with increased lifespan of biomedical implants. The novelty of our TiO2 nanostructures lies mainly in the high level control over their morphology and roughness by mere compositional change and optimisation of the experimental parameters. The present work focuses on the wetting behaviour of various nanostructured titanium surfaces towards water. Kinetics of contact area of water droplet on macroscopically flat, nanoporous and nanotubular titanium surface topologies was monitored under similar evaporation conditions. The contact area of the water droplet on hydrophobic titanium planar surface (foil) was found to decrease during evaporation, whereas the contact area of the droplet on hydrophobic nanorough titanium surfaces practically remained unaffected until the complete evaporation. This demonstrates that the surface morphology and roughness at the nanoscale level substantially affect the titanium dioxide surface-water droplet interaction, opposing to previous observations for microscale structured surfaces. The difference in surface topographic nanofeatures of nanostructured titanium surfaces could be correlated not only with the time-dependency of the contact area, but also with time-dependency of the contact angle and electrochemical properties of these surfaces.

  20. Appcelerator Titanium business application development cookbook

    Bahrenberg, Benjamin


    Presented in easy to follow, step by step recipes, this guide is designed to lead you through the most important aspects of application design.Titanium developers who already have a basic knowledge of working with Appcelerator Titanium but want to further develop their knowledge for use with business applications

  1. Reducing beam hardening effects and metal artefacts using Medipix3RX: With applications from biomaterial science

    Rajendran, K; de Ruiter, N J A; Chernoglazov, A I; Panta, R K; Butler, A P H; Butler, P H; Bell, S T; Anderson, N G; Woodfield, T B F; Tredinnick, S J; Healy, J L; Bateman, C J; Aamir, R; Doesburg, R M N; Renaud, P F; Gieseg, S P; Smithies, D J; Mohr, J L; Mandalika, V B H; Opie, A M T; Cook, N J; Ronaldson, J P; Nik, S J; Atharifard, A; Clyne, M; Bones, P J; Bartneck, C; Grasset, R; Schleich, N; Billinghurst, M


    This paper discusses methods for reducing beam hardening effects using spectral data for biomaterial applications. A small-animal spectral scanner operating in the diagnostic energy range was used. We investigate the use of photon-processing features of the Medipix3RX ASIC in reducing beam hardening and associated artefacts. A fully operational charge summing mode was used during the imaging routine. We present spectral data collected for metal alloy samples, its analysis using algebraic 3D reconstruction software and volume visualisation using a custom volume rendering software. Narrow high energy acquisition using the photon-processing detector revealed substantial reduction in beam hardening effects and metal artefacts.

  2. Local hardening evaluation of carbon steels by using frequency sweeping excitation and spectrogram method

    Tsuchida, Yuji; Kudo, Yuki; Enokizono, Masato


    This paper presents our proposed frequency sweeping excitation and spectrogram method (FSES method) by a magnetic sensor for non-destructive testing of hardened low carbon steels. This method can evaluate the magnetic properties of low carbon steels which were changed after induction heating treatment. It was examined by our proposed method that the degrees of yield strength of low carbon steels were varied depending on hardened conditions. Moreover, it was made clear that the maximum magnetic field strength, Hmax, derived from the measured B-H loops was very sensitive to the hardening if the surface of the samples were flat.


    V. A. Tomilo


    Full Text Available Various schemes of ultrasonic oscillatory system are developed: with a «force nonsensitive» support, with a «force sensitive» support, with the deforming steel balls in bulk. Results of the ultrasonic treatment showed that hardening of a surface of the samples took place when the vibration amplitude of a radiator exceeds a certain level. The level of hardening increases with increase in amplitude of fluctuations of a radiator. Higher level of hardening is registered when the surface is treated by steel balls.

  4. Application of inverse models and XRD analysis to the determination of Ti-17 {beta}-phase coefficients of thermal expansion

    Freour, S. [GeM, Institut de Recherche en Genie Civil et Mecanique (UMR CNRS 6183), Universite de Nantes, Ecole Centrale de Nantes, 37 Boulevard de l' Universite, BP 406, 44 602 Saint-Nazaire cedex (France)]. E-mail:; Gloaguen, D. [GeM, Institut de Recherche en Genie Civil et Mecanique (UMR CNRS 6183), Universite de Nantes, Ecole Centrale de Nantes, 37 Boulevard de l' Universite, BP 406, 44 602 Saint-Nazaire cedex (France); Francois, M. [Laboratoire des Systemes Mecaniques et d' Ingenierie Simultanee (LASMIS FRE CNRS 2719), Universite de Technologie de Troyes, 12 Rue Marie Curie, BP 2060, 10010 Troyes (France); Guillen, R. [GeM, Institut de Recherche en Genie Civil et Mecanique (UMR CNRS 6183), Universite de Nantes, Ecole Centrale de Nantes, 37 Boulevard de l' Universite, BP 406, 44 602 Saint-Nazaire cedex (France)


    scope of this work is the determination of the coefficients of thermal expansion of the Ti-17 {beta}-phase. A rigorous inverse thermo-elastic self-consistent scale transition micro-mechanical model extended to multi-phase materials was used. The experimental data required for the application of the inverse method were obtained from both the available literature and especially dedicated X-ray diffraction lattice strain measurements performed on the studied ({alpha} + {beta}) two-phase titanium alloy.

  5. Interfacial reaction kinetics of coated SiC fibers with various titanium alloys

    Gundel, D. B.; Wawner, F. E.


    The kinetics of the reaction between the silicon carbide fibers and the titanium-based alloy matrix was investigated at temperatures from 800 to 1000 C for several titanium-based alloys (including Ti-1100 alloy and BETA 21S) and unalloyed Ti, reinforced with coated silicon carbide fiber SCS-6. The reaction zone growth kinetics was studied by exposing vacuum encapsulated samples to temperatures from 700 to 1000 C for times up to 150 hrs, followed by SAM observations of samples which were polished perpendicular to the fiber axis and etched. It was found that the reaction zone growth kinetics of the alpha (hcp) and beta (bcc) phases of unalloyed titanium reacting with SCS-6 fibers exhibited different values of the apparent activation energy and of the preexponential factor. Additions of other metals to Ti was found to slow down the reaction kinetics. Among the alloys studied, the Ti-1100 was the slowest reacting conventional alloy and the Ti-14Al-21Nb (in wt pct) was the slowest overall.

  6. Non Radiation Hardened Microprocessors in Spaced Based Remote Sensing Systems

    Decoursey, Robert J.; Estes, Robert F.; Melton, Ryan


    The CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) mission is a comprehensive suite of active and passive sensors including a 20Hz 230mj Nd:YAG lidar, a visible wavelength Earth-looking camera and an imaging infrared radiometer. CALIPSO flies in formation with the Earth Observing System Post-Meridian (EOS PM) train, provides continuous, near-simultaneous measurements and is a planned 3 year mission. CALIPSO was launched into a 98 degree sun synchronous Earth orbit in April of 2006 to study clouds and aerosols and acquires over 5 gigabytes of data every 24 hours. The ground track of one CALIPSO orbit as well as high and low intensity South Atlantic Anomaly outlines is shown. CALIPSO passes through the SAA several times each day. Spaced based remote sensing systems that include multiple instruments and/or instruments such as lidar generate large volumes of data and require robust real-time hardware and software mechanisms and high throughput processors. Due to onboard storage restrictions and telemetry downlink limitations these systems must pre-process and reduce the data before sending it to the ground. This onboard processing and realtime requirement load may mean that newer more powerful processors are needed even though acceptable radiation-hardened versions have not yet been released. CALIPSO's single board computer payload controller processor is actually a set of four (4) voting non-radiation hardened COTS Power PC 603r's built on a single width VME card by General Dynamics Advanced Information Systems (GDAIS). Significant radiation concerns for CALIPSO and other Low Earth Orbit (LEO) satellites include the South Atlantic Anomaly (SAA), the north and south poles and strong solar events. Over much of South America and extending into the South Atlantic Ocean the Van Allen radiation belts dip to just 200-800km and spacecraft entering this area are subjected to high energy protons and experience higher than normal Single Event Upset

  7. Stress-corrosion cracking of titanium alloys.

    Blackburn, M. J.; Feeney, J. A.; Beck, T. R.


    In the light of research material published up to May 1970, the current understanding of the experimental variables involved in the stress-corrosion cracking (SCC) behavior of titanium and its alloys is reviewed. Following a brief summary of the metallurgy and electrochemistry of titanium alloys, the mechanical, electrochemical, and metallurgical parameters influencing SCC behavior are explored with emphasis on crack growth kinetics. Macro- and microfeatures of fractures are examined, and it is shown that many transgranular SCC failures exhibit morphological and crystallographic features similar to mechanical cleavage failures. Current SCC models are reviewed with respect to their ability to explain the observed SCC behavior of titanium and its alloys. Possible methods for eliminating or minimizing stress corrosion hazards in titanium or titanium alloy components are described.

  8. [Use of titanium alloys for medical instruments].

    Feofilov, R N; Chirkov, V K; Levin, M V


    On the ground of an analysis into properties of titanium and its alloys the fields of their possible utilization for making various medical instruments are proposed. Because of their insufficient hardness and wear-resistance the titanium alloys cannot be recommended for making medical instruments with thin cutting edges. For the reasons of their insufficient strength, low wear-resistance and substandard modulus of elasticity, it is inexpedient to use titanium alloys in making many types of clamping medical instruments. Nor is it advisable to employ titanium alloys in handles of the instruments, for this may lead to a contact corrosion of their working parts. The use of titanium alloys is recommended for making bone-joining members, retracting medical instruments, of the spatula and speculum types, some kinds of non-magnetic pincers and ultrasonic medical instruments.

  9. Titanium processing using selective laser sintering

    Harlan, Nicole Renee


    A materials development workstation specifically designed to test high temperature metal and metal-matrix composites for direct selective laser sintering (SLS) was constructed. Using the workstation, a titanium-aluminum alloy was sintered into single layer coupons to demonstrate the feasibility of producing titanium components using direct SLS. A combination of low temperature indirect SLS and colloidal infiltration was used to create "partially-stabilized" zirconia molds for titanium casting. The base material, stabilized zirconia mixed with a copolymer, was laser sintered into the desired mold geometry. The copolymer was pyrolyzed and replaced by a zirconia precursor. The flexural strength and surface roughness of the SLS-produced casting molds were sufficient for titanium casting trials. A laser-scanned human femur was used as the basis for a mold design and technology demonstration. Titanium castings produced from SLS molds exhibited typical as-cast microstructures and an average surface roughness (Ra) of 8 mum.

  10. Welding and Joining of Titanium Aluminides

    Jian Cao


    Full Text Available Welding and joining of titanium aluminides is the key to making them more attractive in industrial fields. The purpose of this review is to provide a comprehensive overview of recent progress in welding and joining of titanium aluminides, as well as to introduce current research and application. The possible methods available for titanium aluminides involve brazing, diffusion bonding, fusion welding, friction welding and reactive joining. Of the numerous methods, solid-state diffusion bonding and vacuum brazing have been most heavily investigated for producing reliable joints. The current state of understanding and development of every welding and joining method for titanium aluminides is addressed respectively. The focus is on the fundamental understanding of microstructure characteristics and processing–microstructure–property relationships in the welding and joining of titanium aluminides to themselves and to other materials.

  11. Forward-Looking Betas

    Christoffersen, Peter; Jacobs, Kris; Vainberg, Gregory

    -looking. This paper introduces a radically different approach to estimating market betas. Using the tools in Bakshi and Madan (2000) and Bakshi, Kapadia and Madan (2003) we employ the information embedded in the prices of individual stock options and index options to compute our forward-looking market beta......Few issues are more important for finance practice than the computation of market betas. Existing approaches compute market betas using historical data. While these approaches differ in terms of statistical sophistication and the modeling of the time-variation in the betas, they are all backward...... at the daily frequency. This beta can be computed using option data for a single day, and is able to reflect sudden changes in the structure of the underlying company. Based on an empirical investigation of daily cross-sections of option contracts on thirty underlying companies, we conclude that these forward...

  12. Betting against Beta

    Frazzini, Andrea; Heje Pedersen, Lasse


    We present a model with leverage and margin constraints that vary across investors and time. We find evidence consistent with each of the model's five central predictions: (1) Because constrained investors bid up high-beta assets, high beta is associated with low alpha, as we find empirically for......, the return of the BAB factor is low. (4) Increased funding liquidity risk compresses betas toward one. (5) More constrained investors hold riskier assets....... for US equities, 20 international equity markets, Treasury bonds, corporate bonds, and futures. (2) A betting against beta (BAB) factor, which is long leveraged low-beta assets and short high-beta assets, produces significant positive risk-adjusted returns. (3) When funding constraints tighten...

  13. Betting Against Beta

    Frazzini, Andrea; Heje Pedersen, Lasse

    We present a model with leverage and margin constraints that vary across investors and time. We find evidence consistent with each of the model’s five central predictions: (1) Since constrained investors bid up high-beta assets, high beta is associated with low alpha, as we find empirically for U...... of the BAB factor is low; (4) Increased funding liquidity risk compresses betas toward one; (5) More constrained investors hold riskier assets........S. equities, 20 international equity markets, Treasury bonds, corporate bonds, and futures; (2) A betting-against-beta (BAB) factor, which is long leveraged low beta assets and short high-beta assets, produces significant positive risk-adjusted returns; (3) When funding constraints tighten, the return...

  14. Attachment and growth behaviour of human gingival fibroblasts on titanium and zirconia ceramic surfaces

    Pae, Ahran; Kim, Hyeong-Seob; Woo, Yi-Hyung [Department of Prosthodontics, School of Dentistry, Kyung Hee University, 1 Hoegi-dong, Dongdaemun-gu, Seoul 130-701 (Korea, Republic of); Lee, Heesu [Department of Oral Anatomy, School of Dentistry, Kangnung National University, Gibyun-dong, Kangnung 210-702 (Korea, Republic of); Kwon, Yong-Dae, E-mail:, E-mail:, E-mail:, E-mail:, E-mail: [Department of Oral and Maxillofacial Surgery, School of Dentistry, Kyung Hee University, 1 Hoegi-dong, Dongdaemun-gu, Seoul 130-701 (Korea, Republic of)


    The attachment, growth behaviour and the genetic effect of human gingival fibroblasts (HGF) cultured on titanium and different zirconia surfaces were investigated. HGF cells were cultured on (1) titanium discs with a machined surface, (2) yttrium-stabilized tetragonal zirconia polycrystals (Y-TZP) with a smooth surface and (3) Y-TZP with 100{mu}m grooves. The cell proliferation activity was evaluated through a MTT assay at 24 h and 48 h, and the cell morphology was examined by SEM. The mRNA expression of integrin-beta1, type I and III collagen, laminin and fibronectin in HGF were evaluated by RT-PCR after 24 h. From the MTT assay, the mean optical density values for the titanium and grooved zirconia surfaces after 48 h of HGF adhesion were greater than the values obtained for the smooth zirconia surfaces. SEM images showed that more cells were attached to the grooves, and the cells appeared to follow the direction of the grooves. The results of RT-PCR suggest that all groups showed comparable fibroblast-specific gene expression. A zirconia ceramic surface with grooves showed biological responses that were comparable to those obtained with HGF on a titanium surface.

  15. Titanium dioxide nanomaterials for photocatalysis

    Liu, Yan; Li, Zhe; Green, Michael; Just, Michael; Li, Yang Yang; Chen, Xiaobo


    Titanium dioxide (TiO2) has been long regarded as one of the more promising photocatalysts to remove environmental pollution and to generate hydrogen from water under sunlight irradiation via photocatalysis. TiO2 is environmentally benign and thus is considered a ‘green’ catalyst. In this review we present a short introduction to the physical and electronic properties of TiO2, its photocatalytic mechanisms, and some recent examples of various TiO2 materials used for photocatalysis; these examples include 0, 1, 2, 3D, faceted, defected, composited, and hydrogenated TiO2 materials.


    V. I. Serebrovskii


    Full Text Available Summary. Currently in the repair and manufacture at the stage of recovery of steel parts, widely used special coatings formed by electrolytic effects on ferrous ions. This technique offers high performance, ease of implementation, low cost of technological equipment and materials used, as well as easy automation of the process. However, this method has several disadvantages: low fatigue strength of reconditioned parts, insufficiently strong grip of the iron coating to the substrate, particularly in alloy steels, insufficient wear resistance. For the purpose of increasing durability and wear resistance of parts, restored through electrochemical action, it is proposed to use chemical-heat treatment, consisting in the application of carbonitriding. Investigated the efficacy of different modes of carbonitriding in the highly carburizing paste-and their influence on the structure and properties of iron plating. It is established that the nitrocarburizing both low and high temperatures repeatedly (6-7.5 times increases the microhardness of the coatings. The highest hardness is obtained by low-temperature carbonitriding with direct quenching in water. Conducting the carbonitriding process at low temperatures (650 °C, significantly increases the hardness of the iron coatings, increasing the limit of its fluidity, a and also greatly increases its endurance limit. Nitrocarburized fatigue strength of samples with iron precipitation on the surface, as shown by our studies, not only higher strength of the same samples without carbonitriding (more than 2 times, but higher than the fatigue strength of the base metal without coatings. Raising the temperature of the carbonitriding did not increase the hardness of electrolytic iron. Developed a rational technology of hardening of steel parts, re-chain iron fortification. Selected optimum conditions for carbonitriding hardening restored iron fortification, with the purpose of increasing durability of machine

  17. NINJA: a noninvasive framework for internal computer security hardening

    Allen, Thomas G.; Thomson, Steve


    Vulnerabilities are a growing problem in both the commercial and government sector. The latest vulnerability information compiled by CERT/CC, for the year ending Dec. 31, 2002 reported 4129 vulnerabilities representing a 100% increase over the 2001 [1] (the 2003 report has not been published at the time of this writing). It doesn"t take long to realize that the growth rate of vulnerabilities greatly exceeds the rate at which the vulnerabilities can be fixed. It also doesn"t take long to realize that our nation"s networks are growing less secure at an accelerating rate. As organizations become aware of vulnerabilities they may initiate efforts to resolve them, but quickly realize that the size of the remediation project is greater than their current resources can handle. In addition, many IT tools that suggest solutions to the problems in reality only address "some" of the vulnerabilities leaving the organization unsecured and back to square one in searching for solutions. This paper proposes an auditing framework called NINJA (acronym for Network Investigation Notification Joint Architecture) for noninvasive daily scanning/auditing based on common security vulnerabilities that repeatedly occur in a network environment. This framework is used for performing regular audits in order to harden an organizations security infrastructure. The framework is based on the results obtained by the Network Security Assessment Team (NSAT) which emulates adversarial computer network operations for US Air Force organizations. Auditing is the most time consuming factor involved in securing an organization's network infrastructure. The framework discussed in this paper uses existing scripting technologies to maintain a security hardened system at a defined level of performance as specified by the computer security audit team. Mobile agents which were under development at the time of this writing are used at a minimum to improve the noninvasiveness of our scans. In general, noninvasive

  18. Imperfect World of $\\beta\\beta$-decay Nuclear Data Sets

    Pritychenko, B


    The precision of double-beta ($\\beta\\beta$) decay experimental half lives and their uncertainties is reanalyzed. The method of Benford's distributions has been applied to nuclear reaction, structure and decay data sets. First-digit distribution trend for $\\beta\\beta$-decay T$_{1/2}^{2\

  19. Synthesis and physicochemical characterization of titanium oxide and sulfated titanium oxide obtained by thermal hydrolysis of titanium tetrachloride

    H. Esteban Benito


    Full Text Available This work reports the synthesis of titanium oxide (TiO2 and sulfated titanium oxide (TiO2-SO4(2- obtained by thermal hydrolysis of titanium tetrachloride. Titanium hydroxide synthesized by this method was impregnated with a 1 N H2SO4 solution, to give amounts of sulfate ions (SO4(2- of 3 and 7 wt%. The synthesized samples were dried at 120 °C during 24 h and then calcined for 3 h at 400 °C. Thermal analyses, X-ray diffraction, nitrogen physisorption, infrared spectroscopy, potentiometric titration with n-butylamine, U.V.-visible diffuse reflectance spectroscopy and scanning electron microscopy were used to characterize the materials. The results of physicochemical characterization revealed that a mixture of crystalline structures, anatase, brookite and rutile developed in the titanium oxide, stabilizing the anatase structure in the sulfated titanium oxides, and coexisting with a small amount of brookite structure. The synthesized mesoporous materials developed specific surface areas between 62 and 70 m² g-1, without detecting an important influence of sulfation on this parameter. The presence of sulfate ions improved the acidity of titanium oxide and modified the characteristics of light absorption in the 425-600 nm region, which suggests the possibility of using these materials in reactions assisted by visible light.

  20. Characterisation of titanium-titanium boride composites processed by powder metallurgy techniques

    Selva Kumar, M., E-mail: [Department of Mechanical Engineering, Dr. Mahalingam College of Engineering and Technology, Pollachi-642003 (India); Chandrasekar, P.; Chandramohan, P. [School of Engineering, Professional Group of Institutions, Coimbatore-641662 (India); Mohanraj, M. [Department of Mechanical Engineering, Info Institute of Engineering, Coimbatore-641107 (India)


    In this work, a detailed characterisation of titanium-titanium boride composites processed by three powder metallurgy techniques, namely, hot isostatic pressing, spark plasma sintering and vacuum sintering, was conducted. Two composites with different volume percents of titanium boride reinforcement were used for the investigation. One was titanium with 20% titanium boride, and the other was titanium with 40% titanium boride (by volume). Characterisation was performed using X-ray diffraction, electron probe micro analysis - energy dispersive spectroscopy and wavelength dispersive spectroscopy, image analysis and scanning electron microscopy. The characterisation results confirm the completion of the titanium boride reaction. The results reveal the presence of titanium boride reinforcement in different morphologies such as needle-shaped whiskers, short agglomerated whiskers and fine plates. The paper also discusses how mechanical properties such as microhardness, elastic modulus and Poisson's ratio are influenced by the processing techniques as well as the volume fraction of the titanium boride reinforcement. - Highlights: Black-Right-Pointing-Pointer Ti-TiB composites were processed by HIP, SPS and vacuum sintering. Black-Right-Pointing-Pointer The completion of Ti-TiB{sub 2} reaction was confirmed by XRD, SEM and EPMA studies. Black-Right-Pointing-Pointer Hardness and elastic properties of Ti-TiB composites were discussed. Black-Right-Pointing-Pointer Processing techniques were compared with respect to their microstructure.

  1. Femtosecond laser-induced periodic surface structures on steel and titanium alloy for tribological applications

    Bonse, J.; Koter, R.; Hartelt, M.; Spaltmann, D.; Pentzien, S.; Höhm, S.; Rosenfeld, A.; Krüger, J.


    Laser-induced periodic surface structures (LIPSS, ripples) were generated on stainless steel (100Cr6) and titanium alloy (Ti6Al4V) surfaces upon irradiation with multiple femtosecond laser pulses (pulse duration 30 fs, central wavelength 790 nm). The experimental conditions (laser fluence, spatial spot overlap) were optimized in a sample-scanning geometry for the processing of large surface areas (5 × 5 mm2) covered homogeneously by the nanostructures. The irradiated surface regions were subjected to white light interference microscopy and scanning electron microscopy revealing spatial periods around 600 nm. The tribological performance of the nanostructured surface was characterized by reciprocal sliding against a ball of hardened steel in paraffin oil and in commercial engine oil as lubricants, followed by subsequent inspection of the wear tracks. For specific conditions, on the titanium alloy a significant reduction of the friction coefficient by a factor of more than two was observed on the laser-irradiated (LIPSS-covered) surface when compared to the non-irradiated one, indicating the potential benefit of laser surface structuring for tribological applications.

  2. An Experimental Investigation for Wear Rate Optimization on Different Gear Materials Using Hardening

    Abhijeet sing v Makwana


    Full Text Available An Experimental Investigation for Wear Rate Optimization on Different Gear Materials (EN8, 8620 & MILD STEEL Using Hardening.” mainly focuses on the mechanical design and analysis of gearbox as transmit the power and live long life. Gears play an essential role in the performance of many products that we rely on in our everyday lives. Gears are mainly used in lathes machines, automobiles and all torque transmitting units. The improved mechanical properties achieved by hardening process. This research focuses on optimizing wear rate of different gear materials using hardening process. The main Objective of this research is to find out the best material for manufacturing gear by hardening process.

  3. Equivalent Plastic Strain Gradient Plasticity with Grain Boundary Hardening and Comparison to Discrete Dislocation Dynamics

    Bayerschen, E; Wulfinghoff, S; Weygand, D; Böhlke, T


    The gradient crystal plasticity framework of Wulfinghoff et al. [53] incorporating an equivalent plastic strain and grain boundary yielding, is extended with additional grain boundary hardening. By comparison to averaged results from many discrete dislocation dynamics (DDD) simulations of an aluminum type tricrystal under tensile loading, the new hardening parameter in the continuum model is calibrated. It is shown that although the grain boundaries (GBs) in the discrete simulations are impenetrable, an infinite GB yield strength corresponding to microhard GB conditions, is not applicable in the continuum model. A combination of a finite GB yield strength with an isotropic bulk Voce hardening relation alone also fails to model the plastic strain profiles obtained by DDD. Instead, a finite GB yield strength in combination with GB hardening depending on the equivalent plastic strain at the GBs is shown to give a better agreement to DDD results. The differences in the plastic strain profiles obtained in DDD simu...

  4. Numerical predicting of the structure and stresses state in hardened element made of tool steel

    A. Bokota


    Full Text Available The paper presents numerical model of thcrmal phcnomcna, phasc transformation and mcchanical phcnomcna associated with hardeningof carbon tool steel. Model for evaluation or fractions OF phases and their kinetics bascd on continuous heating diagram (CHT andcontinuous cooling diagram (CCT. The stresses generated during hardening were assumed to rcsult from ~hermal load. stntcturaI plasticdeformations and transformation plasricity. Thc hardened material was assumed to be elastic-plastic, and in ordcr to mark plastic strains the non-isothermal plastic law of flow with the isotropic hardening and condition plasticity of Huber-Misses were used. TherrnophysicaI values of mechanical phenomena dependent on bo~hth e phase composition and temperature. In the numerical example thc simulated estimation of the phasc Fraction and strcss distributions in the hardened axisimmetrical elemcnt was performed.

  5. Model Identification and FE Simulations: Effect of Different Yield Loci and Hardening Laws in Sheet Forming

    Flores, P.; Duchêne, L.; Lelotte, T.; Bouffioux, C.; El Houdaigui, F.; Van Bael, A.; He, S.; Duflou, J.; Habraken, A. M.


    The bi-axial experimental equipment developed by Flores enables to perform Baushinger shear tests and successive or simultaneous simple shear tests and plane-strain tests. Such experiments and classical tensile tests investigate the material behavior in order to identify the yield locus and the hardening models. With tests performed on two steel grades, the methods applied to identify classical yield surfaces such as Hill or Hosford ones as well as isotropic Swift type hardening or kinematic Armstrong-Frederick hardening models are explained. Comparison with the Taylor-Bishop-Hill yield locus is also provided. The effect of both yield locus and hardening model choice will be presented for two applications: Single Point Incremental Forming (SPIF) and a cup deep drawing.

  6. A 45 nm Low Cost, Radiation Hardened, Platform Based Structured ASIC Project

    National Aeronautics and Space Administration — The proposed 45 nm radiation hardened platform based structured ASIC architecture offers the performance and density expected of a custom ASIC with the low...


    L. A. Glazkov


    Full Text Available The BNTU has developed a technological process for large-size stamp hardening by means of a water-air mixture.  The  basic  requirements  imposed on an hardening  installation using  a  water-air mixture are the following: provision of smooth cooling of a part in order to achieve the required  hardness and structure; possibility of machining parts of various sizes; change of modes for machining parts of various grades of steel according to any hardness rate.The peculiar features of the given installation are: a presence of microprocessor control of water-air mixture supply, possibility of simultaneous machining of a stamp set (2 parts and position change of parts to be hardened in the process of thermal treatment.Installation for large-sized stamp hardening has been manufactured and introduced at theMinskplant of special tools and machining attachments.

  8. Influence of the Hardener Proportion on Mechanical Properties of Adhesive Bonds Used in Agriculture

    Valášek P.


    Full Text Available Joining materials by adhesive bonding is used across all industrial branches. The occurrence of adhesive bonds in machine constructions is still more frequent because of the development of adhesives which are able to meet various requirements of designers. This trend is observable also in agriculture - in the construction of agricultural machines. There even exists a cooperation between the companies developing the adhesives and the agricultural machines producers. The production process of machines and equipment must consider a required production tact. Adhesives and the process of their hardening have to meet these requirements. In the sphere of agriculture, epoxy resins hardening based either on hardeners or heating are used. Mechanical properties of two-component epoxy resins depending on variable amount of the hardener starting crosslinking of these reactoplastics are described.

  9. Process-Hardened, Multi-Analyte Sensor for Characterizing Rocket Plum Constituents Under Test Environment Project

    National Aeronautics and Space Administration — This STTR project aims to develop a process-hardened, simple and low cost multi-analyte sensor for detecting components of rocket engine plumes. The sensor will be...

  10. Work-hardening behavior of mild steel under cyclic deformation at finite strains

    Hu, Z. (Univ. Paris-Nord, Villetaneuse (France))


    The work-hardening behavior of mild steel under monotonic deformation at large shears and cyclic deformation under a wide range of shear amplitudes (from 3 to 34%) has been experimentally investigated and modeled. The influence of shear amplitude, the effect of the amount of pre-shear and that of pre-cyclic deformation have been studied. Considering the evolution of both polarized persistent dislocation structures and no-polarized low-energy dislocation configurations, a physically-based phenomenological model with four internal variables has been proposed. The model explains the cyclic hardening behavior at large strains, the work-hardening stagnation followed by a resumption of work-hardening under Bauschinger deformation with large pre-strains and under cyclic deformation with moderate strain amplitudes. A good qualitative and quantitative agreement has been achieved between experimental results and model predictions.

  11. The Use of Fuzzy Systems for Forecasting the Hardenability of Steel

    Sitek W.


    Full Text Available The goal of the research carried out was to develop the fuzzy systems, allowing the determination of the Jominy hardenability curve based on the chemical composition of structural steels for quenching and tempering. Fuzzy system was created to calculate hardness of the steel, based on the alloying elements concentrations, and to forecast the hardenability curves. This was done based on information from the PN-EN 10083-3: 2008. Examples of hardenability curves calculated for exemplar steels were presented. Results of the research confirmed that fuzzy systems are a useful tool in evaluation the effect of alloying elements on the properties of materials compared to conventional methods. It has been demonstrated the practical usefulness of the developed models which allows forecasting the steels’ Jominy hardenability curve.

  12. Investigations of high-frequency induction hardening process for piston rod of shock absorber

    Xianhua Cheng; Qianqian Shangguan


    The microhardness of piston rods treated with different induction hardening processes was tested. The experimental results reveal that the depth of the hardened zone is proportional to the ratio of the moving speed of the piston rod to the output power of the induction generator. This result is proved correct through the Finite Element Method (FEM) simulation of the thermal field of induction heating. From tensile and impact tests, an optimized high frequency induction hardening process for piston rods has been obtained, where the output power was 82%×80 kW and the moving speed of workpiece was 5364 mm/min. The piston rods, treated by the optimized high frequency induction hardening process, show the best comprehensive mechanical performance.

  13. The sub-zero Celsius treatment of precipitation hardenable semi-austenitic stainless steel

    Villa, Matteo; Hansen, Mikkel Fougt; Somers, Marcel A. J.


    A precipitation hardenable semi-austenitic stainless steel AISI 632 grade was austenitized according to industrial specifications and thereafter subjected to isothermal treatment at sub-zero Celsius temperatures. During treatment, austenite transformed to martensite. The isothermal austenite...

  14. Induction hardening of tool steel for heavily loaded aircraft engine components

    Rokicki P.


    Full Text Available Induction hardening is an innovative process allowing modification of the materials surface with more effective, cheaper and more reproducible way to compare with conventional hardening methods used in the aerospace industry. Unfortunately, high requirements and strict regulation concerning this branch of the industry force deep research allowing to obtain results that would be used for numerical modelling of the process. Only by this way one is able to start the industrial application of the process. The main scope of presented paper are results concerning investigation of microstructure evolution of tool steel after single-frequency induction hardening process. The specimens that aim in representing final industrial products (as heavily loaded gears, were heat- -treated with induction method and subjected to metallographic preparation, after which complex microstructure investigation was performed. The results obtained within the research will be a basis for numerical modelling of the process of induction hardening with potential to be introduced for the aviation industrial components.

  15. Observation of a New Mechanism Balancing Hardening and Softening in Metals

    Yu, Tianbo; Hansen, Niels; Huang, Xiaoxu


    Plastic deformation of metals refines the microstructure and increases the strength through work hardening, but this effect of deformation is counterbalanced by dynamic recovery. After large strain, the microstructure typically shows a lamellar morphology, with finely spaced lamellar boundaries c...

  16. Radiation-Hardened, Substrate-Removed, Metamorphic InGaAs Detector Arrays Project

    National Aeronautics and Space Administration — High-performance radiation-hardened metamorphic InGaAs imaging arrays sensitive from the ultraviolet (UV) through the short-wavelength infrared (SWIR) will be...

  17. Monitoring of hardening and hygroscopic induced strains in a calcium phosphate bone cement using FBG sensor.

    Bimis, A; Karalekas, D; Bouropoulos, N; Mouzakis, D; Zaoutsos, S


    This study initially deals with the investigation of the induced strains during hardening stage of a self-setting calcium phosphate bone cement using fiber-Bragg grating (FBG) optical sensors. A complementary Scanning Electron Microscopy (SEM) investigation was also conducted at different time intervals of the hardening period and its findings were related to the FBG recordings. From the obtained results, it is demonstrated that the FBG response is affected by the microstructural changes taking place when the bone cement is immersed into the hardening liquid media. Subsequently, the FBG sensor was used to monitor the absorption process and hygroscopic response of the hardened and dried biocement when exposed to a liquid/humid environment. From the FBG-based calculated hygric strains as a function of moisture concentration, the coefficient of moisture expansion (CME) of the examined bone cement was obtained, exhibiting two distinct linear regions.

  18. Flywheel starter ring gear failures and hardness variation reduction in surface hardening process

    Selçuk Can Yücel


    This technical paper summarizes the case study conducted for truck flywheel starter ring gears with diameter of 470 mm in order to reduce hardness variation by optimization of induction hardening and tempering processes.

  19. Analysis by design of experiments of distortion potentials in drawn and induction hardened wire

    Alexandre da Silva Rocha


    Full Text Available In this investigation a DoE (Design of Experiments analysis of distortion for a typical manufacturing process of pre-straightened, cold drawn and induction hardened AISI 1045 cylindrical steel bars was carried out. A careful characterization of the material, including residual stress states and geometrical changes, was done for the different manufacturing steps. In order to identify effects and correlations on distortion behavior, the investigated variables included the drawing process itself with two different drawing angles, a stress relief treatment, which was applied to one part of the samples, and, finally, induction hardening with two different case depths. Main and statistically significant effects on the distortion of the induction hardened samples were found to be in this order, the drawing angle, the stress relief treatment and the induction hardening depth. It was also found that the distortion potentials are transmitted from the drawing process to further manufacturing steps and, consequently, from one production site to the next.

  20. Radiation Hardened Nanobridge based Non-volatile Memory for Space Applications Project

    National Aeronautics and Space Administration — This NASA Phase I SBIR program would develop and demonstrate radiation hardened nanobridge based non-volatile memory (NVM) for space applications. Specifically, we...