钛及钛合金配料的微机控制系统

介绍了钛及钛合金配料微机控制的原理及硬、软件配置。     

The effects of spark anodizing treatment of pure titanium metals and titanium alloys on corrosion characteristics

This study evaluated the surface characteristics of oxide films on commercially pure titanium metals (CP-Ti; Grade 2 and Grade 3) and titanium alloy (Ti6Al4V and Ti6Al7Nb) samples formed by an anodic oxidation treatment, and investigated the effects of anodization on the corrosion characteristics. FE-SEM, XRD, and Raman spectroscopy were used to evaluate the micromorphology and crystalline structure of the oxide films. The corrosion resistance of the sample groups was evaluated using open-circuit potential and cyclic polarization tests. After anodic oxidation up to dielectric breakdown with the same electric current, 150-200 nm-sized pores were distributed homogeneously on pure titanium metal samples, partially occluded pores were observed on the Ti6Al4V alloy, and there was an inhomogeneous size and distribution of pores on the Ti6Al7Nb alloy. The titanium dioxide films formed through anodic oxidation contained a phase mixture of anatase and rutile. The cyclic polarization tests showed that all the tested sample groups were not susceptible to localized corrosion. The as-received and anodically oxidized CP-Ti grade 3 groups showed a higher corrosion resistance than the other groups. The mean E_corr values of the anodically oxidized sample groups, except for the anodized Ti6Al7Nb alloy, showed higher values than those of the respective as-received sample groups. In particular, the Ti6AL7Nb alloy showed a statistically higher E_corr value in the anodized group than in the as-received group (p < 0.05).     

钛及钛合金表面处理技术的应用及发展

目前,钛及钛合金在国民经济和国防工业上的应用越来越广泛,但钛及钛舍金也存在一些固有的缺陷,为了进一步提高和改善其使用特性,需要对其进行表面处理。介绍了一些对钛及钛合金行之有效的先进表面处理技术,如化学处理、阳极氧化处理、化学镀及电镀、微弧氧化、电泳沉积和纳米电沉积等,并对其应用加以讨论和评述。这些表面处理方法大大扩展了钛及钛合金的应用领域,促进了钛及钛舍金在各行业领域的应用。     

Development of a novel cathodic plasma/electrolytic deposition technique part 1: Production of titanium dioxide coatings

A new atmospheric pressure plasma electrolytic deposition process has been developed for the production of crystalline titanium dioxide films on metal substrates. The process occurs in a liquid precursor composed of titanium tetraisopropoxide and absolute ethanol. A plasma discharge is created and confined around the cathode in a superheated vapour sheath surrounded by the liquid phase, inducing the production of a nano-crystalline TiO₂ coating at the surface of the cathode. The analysis of the structure and composition of these TiO₂ coatings have been carried out by Scanning Electron Microscopy, Transmission Electron Microscopy, Raman and X-Ray Photoelectron Spectroscopies and X-Ray Diffraction. The produced crystalline titanium dioxide coatings are very adherent to the substrate and present a dendritic-like structure. We have moreover demonstrated that it is possible to adjust easily its composition by a post-processing calcination. Such characteristics make these films very interesting for photocatalysis, solar cells and gas sensing applications, and promise therefore some useful industrial benefits.     

An overview of power-law creep in polycrystalline β-titanium

A constitutive law for power-law creep of BCC β-Ti is developed, based on experimental data from eight independent studies. The present compilation adds more than twice as many data points as previous analyses, covers nine orders of magnitude in strain rate from 10⁻⁷ to 10² s⁻¹, and incorporates recent data for the shear modulus of β-Ti.     

牙科专用铸钛机

介绍开发研制牙科专用铸钛机的意义，牙科铸钛技术的发展历程，牙科铸钛机的一般结构，几种常用机器的性能特点、使用方法和应用情况。     

Characterization of aluminized layer formation during annealing of Ti coated with an Al film

During annealing of the Ti surface coated by the Al film, different aluminide phases were formed as the result of reactions between Ti and Al. The structural formation of aluminide phases and the microstructure formed after annealing treatment depended on the thickness of the initial Al film. After annealing treatment up to 900 °C, the microstructure of the overlayer clearly showed contours of grain boundaries of the initial Ti substrate. The shapes, sizes and distribution of the particles in the overlayer depended on the microstructure of the initial Ti substrate as well. The microstructure of the initial Ti substrate had a great effect on the transformation kinetics. Retardation of the reaction was observed on the substrate with lamellar structure. After the elimination of the overlayer, a fine plate structure was formed. The change of the phase compositions of the overlayer led to change in the microhardness. The peak value of the microhardness was observed with the lamellar like morphology of overlayer.     

Hot target sputtering: A new way for high-rate deposition of stoichiometric ceramic films

Titanium nitride or dioxide coatings have been reactively sputter-deposited under unstable sputtering conditions using a cold or hot target. We have shown that increasing the sputtered titanium flux in cold target sputtering (CTS), by increasing either the discharge current or the discharge voltage, increases the metalloid content in the coating deposited when the target operates at the higher reactive gas flow rate of the elemental sputtering mode. Using a hot target allows a perfect stabilisation of the process in the presence of an argon-nitrogen discharge, whereas only a slight stabilisation occurs when the sputtering stage takes place in argon-oxygen mixtures. It is shown that the stabilisation effect of hot target sputtering (HTS) is due to the strong increase of reactive species diffusion into the bulk target, which is more pronounced with nitrogen than with oxygen, as soon as the target heats up to the α-Ti→β-Ti transformation temperature.     

Gas nitriding of titanium alloy Timetal 205

Samples of a titanium alloy Timetal 205 were treated by thermochemical gas nitriding using differential scanning calorimeter equipment, in nominally pure nitrogen, at 1040 and 1160 °C for 1, 3 and 5 h. X-ray diffraction analysis of the samples was carried out to identify new phases of chemical compounds in the nitrided layer. Microstructures were analysed using scanning electron microscopy. Cross-sectional microhardness profiles of the samples were obtained using a Knoop indenter.     

Electrochemical Nucleation of Titanium on Platinum

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Nitridation of Ti-6Al-4V powder in thermal plasma conditions and sintering of obtained TiN powder

This study is devoted to plasma nitridation of a Ti-6Al-4V powder, and sintering of reaction products so-obtained.Ti-6Al-4V spherical particles (22-45 μm) were injected in a plasma jet using N₂ as plasma gas and collected in two spots: in a cold area located far from the torch and in a hot area submitted to the plasma thermal effect. After plasma nitridation, particles of substoichiometric titanium nitride (TiN_1−x) with no nitrogen gradient were obtained. The reduction of nitrogen concentration in plasma gas improved the massic output of gathered powders. These powders were not exclusively composed by TiN_1−x, since titanium alloy often remained, and a secondary phase β-Ti containing vanadium and aluminium was always present inside the grains. The nitridation rate depended on the collected area. Titanium oxide (rutile) was detected in powders collected in the hot area.Titanium nitride powders in which no rutile was detected were hot pressed up to 1450 °C under flowing nitrogen. In this case, the densification rate did not overload 83% of theoretical value. This fact can be explained by the nitridation of both TiN_1−x and titanium intermetallic phases during the heat treatment. In the case of inert atmosphere (argon), there was only the densification phenomenon which gave a density close to the theoretical value.This work has to be developed on the one hand to improve powder synthesis and its natural sintering, and on the other hand to approach hot pressing sintering mechanism.     

钛合金的激光切割

研究了不同辅助气体和工艺参数对激光切割钛合金板的影响，分析了激光切割切缝的断面特征和热影响区特点。试验结果表明，用氩气作辅助气体，切割质量最好；激光功率和切割速度对切缝宽度和热影响区宽度有一定影响；切缝断面可分为形貌不同的两个区，两区之间有明显界线；切缝上表面和下表面热影响区宽度不同，特点为上窄下宽。     

耐蚀钛合金的发展与应用

由于工业纯钛难于适应化工、采油等苛刻环境应用，促进了耐蚀钛合金的发展。本文对耐蚀钛合金的设计理论与试验作了分析，并对近期开发的耐蚀钛合金作了介绍，展望了耐蚀钛合金的应用。     

Effect of centrifugal rotational speed on wedge castability of titanium

This study examined the effects of the speed and force in centrifugal casting on the wedge castability of Ti-5 mass%Cu (Ti-5Cu) alloy and commercially pure titanium (CP-Ti). The Ti-5Cu alloy was prepared by argon-arc melting. Whole wedge-shaped acrylic patterns were prepared with either 15° or 30° angles and invested with a MgO-based material. The wedge specimens were cast using a centrifugal casting machine at rotational speeds of 600, 1000, 1250, 1500 and 3000 rpm. Mold filling, an index for a measure of castability, was determined as the missing length between the edge of the cast wedge and the theoretical acute tip of the triangle. CP-Ti was used as a control. An analytical model was developed to relate the mold-filling index to the surface energy and rotational speed. The experimental results indicate that the means of the mold-filling index of the 30° wedge angle were lower than those of the 15° wedge angle when compared for each corresponding metal and rotational speed. In each angle for CP-Ti, the means tended to reduce with increase in the rotational speed. The mold-filling index of 5% Cu titanium was found to be similar to that of CP-Ti, even for 15° wedge when the rotational speed was higher than 1250 rpm. The results suggest that dental prosthesis, which has narrow cross sections containing very narrow regions (for example, clasps of a denture), can be cast successfully by utilizing high rotational speed during centrifugal casting. The complex dependence of mold-filling index on wedge angle and rotational speed is explained on the basis of the analytical model and the dependence of the apparent surface energy on rotation speed.     

牙科钛及钛合金表面烤瓷研究进展

介绍了中国钛工业发展的历史，钛的资源和钛的应用情况以及钛合金发展所取得的进展，中国钛工业经历了４０余年的研究和发展，目前产能已达到年产３６５０ｔ海绵钛和２８００ｔ钛加工材的生产能力，并建立了一个从海绵钛生产到钛锭熔炼，铸造，加工及钛设备制造的完整的钛工业体系，钛材已被广泛用於化学，宇航，航空等各个工业部门。中国已成长为世界上一个重要的钛工业国，同时还总结了中国钛工业发展的经验和教训；展望了中国钛工     

Preparation of TiAl alloy powder by high-energy ball milling and diffusion reaction at low temperature

In this paper, TiAl alloy powders were prepared successfully by high-energy ball milling and diffusion reaction in vacuum at low temperature. The titanium powder, aluminum powder, and titanium hydride powder were used as raw materials. The samples were characterized by scanning electron microscopy(SEM), X-ray diffraction(XRD), field-emission scanning electron microscopy(FESEM), and differential thermal analysis(DTA). The results show that the alloy powders with the main intermetallic compounds of TiAl are obtained using Ti-Al powders and TiH_2-Al powders after heated for 2 h at 500 ℃,3 h at 600 ℃,and 3 h at 750 ℃,respectively.The average grain sizes of alloy powder are about 45 and20 μm with irregular shape, respectively. The prepared TiAl alloy powders are relatively pure, and the average quality content of oxygen in the alloy powders is0.33 wt%. The forming process of alloy powder contains both the diffusion reaction of Ti and Al,which gives priority to the diffusion reaction of aluminum.     

A Quantitative Study on the Effect of Heat Treatment on the Microstructure and Orientation of Titanium Hydride in Electrochemically Hydrogenated Pure Titanium

The electrochemical hydrogen charging of pure titanium and its alloys has been investigated previously, while how a subsequent annealing treatment affects the type of hydride and its orientation relationship with matrix is not clear. In the present study, a quantitative study on the microstructure and orientation of titanium hydrides during electrochemical hydrogen charging and subsequent annealing treatment was carried out using scanning electron microscopy, transmission electron microscopy and electron backscatter diffraction. The results show that δ-hydride is the main in both the electrochemically hydrogenated sample and the subsequent annealing treated sample. After electrochemical hydrogen charging for 48 h, the surface is mainly composed of dense δ-hydride with a thickness of approximately 42 μm, the orientation relationship between α-matrix and δ-hydride follows only the orientation relationship of OR2, {0001}_α//{1$\overline{1}$1}_δ, $\langle 1\overline{2}10\rangle_{\alpha }$//$\langle 110\rangle_{\delta }$ and an interface plane $\{ 10\overline{1}3\}_{\alpha }$//$\{ 1\overline{1}0\}_{\delta }$. Besides OR2, a part of hydrides show an orientation relationship of OR1 with the matrix after annealing, {0001}_α//{001}_δ, $\langle 1\overline{2}10\rangle_{\alpha }$//$\langle 110\rangle_{\delta }$ and an interface plane of $\{ 10\overline{1}0\}_{\alpha }$//$\{ 1\overline{1}0\}_{\delta }$. It is further found that the relative frequency of OR1and OR2 is closely related to annealing duration. Under an argon atmosphere at 450 °C, the frequencies of OR1 and OR2 are nearly balance with an annealing time of 12 h, while OR1 becomes to be the predominant one with a relative frequency of 96.5% after annealing for 96 h. The mechanism for the evolution of orientation relationship of hydrides with annealing time was discussed.     

多层反应塔衬钛层裂纹成因分析

采用金相分析、扫描电镜、X射线衍射及氢含量分析等方法，对多层反应塔衬钛层的裂纹成因进行了分析，由于钛板吸氢形成氢化钛导致材料性能劣化，对此提出了处理意见和监控措施。     

海绵钛/电解钛熔炼TC4钛合金铸锭直接轧制板材的组织及性能

分别以海绵钛和电解钛为原材料熔炼TC4钛合金,将熔炼后的铸锭进行热轧,研究两种原材料熔炼的铸锭轧制为TC4轧板后的组织与性能。结果表明,海绵钛TC4热轧板材组织较电解钛晶粒粗大,组织不均匀,而电解钛TC4热轧板材组织为均匀细长、条状交错的α相,呈现出类似网篮组织结构。海绵钛TC4板材的抗拉强度和洛氏硬度明显高于电解钛TC4钛合金板材,而电解钛TC4板材的塑性更好。海绵钛TC4板材的断裂方式为准解理断裂与韧性断裂的复合断裂,而电解钛TC4板材的断裂方式为韧性断裂。     

The Machining of γ-TiAI Intermetallic Alloys

Titanium intermetallic materials are likely to play a significant role in the production of future aeroengines. The paper details the machinabilty of a range of gamma titanium aluminide (γ-TiAl) intermetallic alloys when turning, grinding, HSM, drilling, EDM and ECM. Comprehensive literature review data is augmented with experimental results for turning, turn-milling and temperature measurement when high speed milling. Despite the ability to produce crack free surfaces when grinding and HSM, turning and drilling remain problematic. Turned surfaces are in general characterised by workpiece smearing, numerous arc shaped cracks, subsurface lamellae deformation and significant strain hardening, although the use of PCD tooling and ultrasonic assisted cutting has been shown to minimise these effects.