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The Ti52Ni47Al1 alloy has 16% volume fraction Ti2Ni particles in the B2 matrix with Ti2Ni particles having a higher Al content than the B2 matrix. Transformation temperatures M* and A* of this alloy are lower than those of the Ti51Ni49 alloy due to the solid solution of the Al atoms. M* and A* decrease with increasing aging time at 400°C because the Al atoms diffuse slightly from the Ti2Ni to the B2 matrix. The hardness increment of this alloy is more than that of the Ti51Ni49 alloy under the same degree of cold rolling. At the same time, M* and A* of this alloy can be more depressed by thermal cycling than those of the Ti51Ni49 alloy, especially in the first ten cycles. All of these features result from the fact that this alloy has a higher inherent hardness due to the solid solution of the Al atoms. This also causes the R-phase transformation to be more easily promoted by both cold rolling and thermal cycling in this alloy. The strengthening effects of cold rolling and thermal cycling on the M* (Ms) temperature of this alloy follows the expression Ms = T0–Ky, in which K values are affected by different strengthening processes. It is found that the higher the inherent hardness of the TiNi and TiNiX alloys, the higher the K values they have. 相似文献
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The objective of this work was to fabricate a suitable porous Ti–10Mo alloy as the human bone replacement implants. The porous Ti–10Mo alloy was fabricated by mechanical alloying and then consolidated by powder metallurgy technique. NH4HCO3 powder was used as space-holder. It was indicated that the mean pore size, porosity, compressive strength, and elastic modulus of porous Ti–10Mo alloy could be tailored by the amount of NH4HCO3, and then could be matched with those of human bones. Furthermore, porous Ti–10Mo alloy was treated by alkali heat treatment and soaked in the 1.5 times simulated body fluid (1.5SBF). It was observed that the surface and the inside pore wall of porous Ti–10Mo alloy with 25 wt.% NH4HCO3 covered with the apatite layer after soaked in 1.5SBF for 28 days. These phenomena indicated that the surface modified porous Ti–10Mo alloy exhibited a high potential for bone-bonding, which was expected to be used as bone tissue implant. 相似文献
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A high-resolution time-of-flight secondary ionization mass spectrometer (TOF-SIMS) has been used to investigate chain length effects in hydrocarbon seff-assembled monolayer (SAM) surfaces on gold substrates. A wide range of n-alkanethiols was used to make homogeneous SAM surfaces, which included both odd and even hydrocarbon chain length thiols. Variations in coverage, extent of oxidation, and high-mass cluster formation as a function of hydrocarbon chain length of the alkanethiol SAM surfaces were investigated. Long-short chain length effects were observed for the relative coverage of the SAM surfaces, which directly influences the extent of oxidation for the thin films. The formation of gold-sulfur and gold-adsorbate cluster ions was also observed, since the mass range of the TOF-SIMS made it possible to monitor all of the cluster ions that were formed following the high-energy ion/surface interactions. 相似文献
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S. Nagarjuna 《Bulletin of Materials Science》2004,27(1):69-71
The thermal conductivity (TC) of peak aged Cu-4.5 wt% Ti alloy was measured at different temperatures and studied its variation
with temperature. It was found that TC increased with increasing temperature. Phonon and electronic components of thermal
conductivity were computed from the results. The alloy exhibits an electronic thermal conductivity of 46.45 W/m.K at room
temperature. The phonon thermal conductivity decreased with increasing temperature from 17.6 at 0 K to 1.75 W/m.K at 298 K,
which agrees with literature that the phonon component of thermal conductivity is insignificant at room temperature. 相似文献
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J. Faure A. Balamurugan H. Benhayoune P. Torres G. Balossier J.M.F. Ferreira 《Materials science & engineering. C, Materials for biological applications》2009,29(4):1252-1257
The present study is an attempt to enhance the apatite-forming ability of titanium metal induced by the alkaline (NaOH) treatment. A cell free culture medium, acellular DMEM solution was utilised to develop bone-like apatite on alkali-treated titanium alloy surface. The main advantage of this process is the development of bone like apatite with essential trace elements on the metallic substrate by using the DMEM culture medium as a soaking medium. The formed apatite deposits were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDXS). The obtained results suggest that the method utilized in this work can be successfully applied to obtain deposition of uniform coatings of crystalline hydroxyapatite on alkali treated titanium substrates. 相似文献
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K2Ti6O13晶须不仅具有优越的力学性能和良好的生物学特性,而且具有与常规Ti合金相近的膨胀系数。本研究尝试选用K2Ti6O13晶须(K2Fi6O13w)作为生物活性涂层材料,利用BCC方法(混合-包埋-煅烧)在Ti合金基体上成功制备了K2Ti6O13w涂层,并对涂层的表面形态、结合强度和生物活性进行了研究。结果表明,涂层由K2Ti6O13晶须和少量的TiO2和K2Ti6O9组成,其表面粗糙多孔。由于膨胀系数的良好匹配,涂层与基体之间具有较高的结合强度,达24MPa。模拟体液培养后,涂层表面沉积了一层多孔的骨状羟基磷灰石,它由平均直径20nm,长200nm的羟基磷灰石纳米线组成,这表明钛酸钾涂层具有良好的生物活性。涂层较高的生物活性与其独特的生化特性和组分密切相关。 相似文献
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Based on the empirical rules for the composition design of bulk metallic glasses, a general composition formula for forming nano/ultrafine-structure is suggested. According to this formula a group of quinary Ti alloys have been developed. By controlling the solidification conditions an in situ formed bimodal microstructure consisting of micrometer-sized dendritic β-Ti solid solution dispersed in a nano/ultrafine-structured matrix has been obtained in these quinary Ti alloys. The β-Ti solid solution contributes to the ductility and the low Young's modulus, while the nano/ultrafine-structured matrix contributes to the high strength. The combination of high strength and low Young's modulus offers potential advantages in biomedical applications. 相似文献
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《Materials Science & Technology》2013,29(5):549-552
AbstractThe semisolid formability for Ti14, an α+Ti2Cu alloy, is compared with the conventional warm formability from the point of forgeability. The forgeability is evaluated by upsetting and die forging tests. The results show that excellent upsettability with the upsetting reduction in height of 70–85% and low upsetting force could be obtained in semisolid state ranging from 1000 to 1100°C, which is better than that in conventional processing. Die forging tests also show excellent workability with a forging ratio of 75% at the temperature range of 1000–1050°C. It can be concluded that the existence of liquid may serve to relax the stress concentrations caused by solid deformation, which causes low deformation resistance and results in improvement of forgeability. Furthermore, dynamic recrystallisation occurred during thixoforging, and the grain refinement was attained, which also results in the improvement of the semisolid formability. 相似文献
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High-temperature deformation behavior of Ti60 titanium alloy 总被引:2,自引:0,他引:2
Weiju Jia Yigang ZhouJianrong Liu Qingjiang Wang 《Materials Science and Engineering: A》2011,528(12):4068-4074
Isothermal compressions of near-alpha Ti60 alloy were carried out on a Gleeble-3800 simulator in the temperature range of 960-1110 °C and strain rate range of 0.001-10.0 s−1. The high-temperature deformation behavior was characterized based on an analysis of the stress-strain behavior, kinetics and processing map. The flow stress behavior revealed greater flow softening in the two-phase field compared with that of single-phase field. In two-phase field, flow softening was caused by break-up and globularization of lamellar α as well as deformation heating during deformation. While in the single-phase field, flow softening was caused by dynamic recovery and recrystallization. Using hyperbolic-sine relationships for the flow stress data, the apparent activation energy was determined to be 653 kJ/mol and 183 kJ/mol for two-phase field and single-phase field, respectively. The processing map exhibited two instability fields: 960-980 °C at 0.3-10 s−1 and 990-1110 °C at 0.58-10 s−1. These fields should be avoided due to the flow localization during the deformation of Ti60 alloy. 相似文献
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S.A. Souza C.R.M. Afonso P.L. Ferrandini A.A. Coelho R. Caram 《Materials science & engineering. C, Materials for biological applications》2009,29(3):1023-1028
Titanium alloys present a combination of properties that makes them suitable materials for various medical applications, and there is special interest in Ti–Cu alloys for the fabrication of dental prostheses. The addition of Cu to Ti lowers the melting point of the alloy, as well as leading to the development of desirable mechanical properties. In this study a eutectoid alloy was prepared and heat treated, then cooled at various cooling rates. The eutectoid structure (α + Ti2Cu) was observed for all cooling rates used, and evidence of α′ martensite was found for cooling rate higher than 9 °C s–1. Lower cooling rates resulted in higher modulus values. This was attributed to the volume fraction of the α and Ti2Cu phases. Higher cooling rates produced structures with lower modulus values and greater hardness, a result attributed mainly to the development of a martensitic structure. 相似文献
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In order to investigate the in vivo behavior of pure magnesium and AZ31B and the influence of mineralization induction ability, sample rods were implanted intramedullary into the femora of rabbits. After one and nine weeks, six animals from each group were sacrificed, respectively. Undecalcified cross-sections of implant were performed to observe bone-implant by scanning electron microscopy (SEM) and energy dispersive spectromicroscopy (EDS). The SEM/EDS evaluation showed that there is a thin layer of bone around magnesium and its alloy after nine-week implantation. The results further showed that the aluminum-zinc containing magnesium alloys AZ31B provided a slower degradation rate in vivo than the pure magnesium. At the locations where magnesium was resorbed, the deposition of new bone was found. The results indicate that magnesium is biocompatible, osteo-conductive and is a potential material for use as a degradable bone implant. 相似文献
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High temperature tensile tests were carried out on L12 type Co3 Ti alloys, both undoped and doped with 1–4 at.-%Fe. There were anomalous increases of the 0·2% yield stress (yield strength) with increasing test temperature from 473 to 1073 K (or 1173 K, depending on the composition). The elongation and ultimate tensile stress (UTS) monotonically decreased with increasing temperature. The fracture surfaces of specimens showed a variety of fracture modes which were dependent on the test temperature and composition. There was a correlation between the ductility and the fracture mode: the more transgranular the fracture mode, the higher the ductility. It was found that Co3 Ti with 2 at.-%Fe exhibited improved ductility and it exhibited the highest peak value of yield strength and peak temperature. The alloys were also hydrogen charged to investigate their hydrogen embrittlement behaviour. Room temperature tests indicated that the addition of 2 at.-%Fe decreased the hydrogen related embrittlement.MST/3479 相似文献