钛--跨入新千年的金属巨人

介绍了海绵钛提取及钛材生产在20世纪的兴起与发展；论述了钛、钛材、钛合金在国民经济各主要工业部门，特别是在高新技术领域的广泛应用与重要作用；展望了钛工业在新千年的市场前景并提出在我国应给予重点发展和关注的建议。     

Challenges in alloy design: Titanium for the aerospace industry

This review describes the principles governing the design of titanium alloys for engine and airframe applications in the aeronautical industry. The relationships between processing, microstructure and properties of the commonly used α + β titanium alloys are described in some detail. The ‘state of science’ is seen to be sufficiently advanced to enable the metallurgist to optimally design this class of alloys to meet specific requirements. The challenges to the alloy designer lie in increasing the temperature capability of titanium alloys, and in standardising processing techniques which will decrease the high manufacturing costs of components.     

The effect of ball milling on the melting behavior of Sn–Cu–Ag eutectic alloy

Sn–Ag–Cu (SAC) solder alloys are the best Pb free alternative for electronic industry. Since their introduction, efforts are made to improve their efficacies by tuning the processing and composition to achieve lower melting point and better wettability. Nanostructured alloys with large boundary content are known to depress the melting points of metals and alloys. In this article we explore this possibility by processing prealloyed SAC alloys close to SAC305 composition (Sn-3wt%Ag-0.5wt%Cu) by mechanical milling which results in the formation of nanostructured alloys. Pulverisette ball mill (P7) and Vibratory ball mills are used to carry out the milling of the powders at room temperature and at lower temperatures (−104 °C), respectively. We report a relatively smaller depression of melting point ranging up to 5 °C with respect to original alloys. The minimum grain sizes achieved and the depression of melting point are similar for both room temperature and low-temperature processed samples. An attempt has been made to rationalize the observations in terms of the basic processes occurring during the milling.     

The Application of the Rare Earths to Magnesium and Titanium Metallurgy in Australia

Rare earth elements (REEs) have found application in metallurgical processes for nearly a century due to their unique chemical and physical properties but have gained increased attention in recent decades. Notably, the use of these elements may assist in the development of advanced magnesium and titanium products for applications spanning biomedicine, aerospace, and the automotive industry. To this end, current progress in this area, highlighting work done in Australian research organizations with particular academic expertise, is reviewed. Two areas that require further research are identified: the application of Sc and the heavy lanthanides to the development of novel magnesium alloys and the use of REEs as additives in the development of additive manufacturing of titanium parts.     

国内外低温钛合金的开发与应用现状

本文主要概述了前苏联、美国、日本、中国等国家在低温钛合金开发的工作进展。指出了目前国内外低温钛合金的应用现状。提供了未来低温钛合金领域的主要发展方向包括降低生产制造成本、重视低温综合性能更佳的钛合金材料研发及其新型成形工艺研究。这将对我国低温钛合金行业的战略规划、技术研发、成果应用等工作的开展起到启示作用。     

Experimental studies on process-induced morphological characteristics of macro- and microstructures in laser consolidated alloys

Laser consolidation (LC) developed by National Research Council’s Industrial Materials Institute (NRC-IMI-London) since mid-1990s, is a laser cladding based rapid manufacturing and material additive process that could fabricate a “net-shape” functional metallic shape through a “layer-upon-layer” deposition directly from a computer aided design model without using molds or dies. In order to evaluate the LC processability of different materials, some representative nickel-based superalloys (IN-625, IN-718, IN-738, and Waspaloy), stainless steels (austenitic SS316L and martensitic SS420), and lightweight alloys (Ti–6Al–4V titanium alloy and Al-4047 aluminum alloy) have been investigated. Like other laser cladding based processes, due to process-induced rapid directional solidification, the LC alloys have demonstrated certain unique morphological characteristics. Moreover, the “as-consolidated” LC alloys, in nature, are in the “as-quenched” state, and some precipitation processes from their matrices, which are sometimes critical to the development of mechanical performance of the materials, could be effectively suppressed or retarded. Post-heat treatments, therefore, could necessarily facilitate the process of achieving their required operational microstructures. In this article, a comprehensive investigation was performed including metallurgical soundness and process-induced morphological characteristics of the LC materials, and microstructure development brought by post-LC heat treatments using optical microscope, scanning electron microscope, and X-ray diffraction. The implications on the mechanical performance of the LC materials were discussed as well in order to provide essential information for potential industrial applications of the LC materials.     

Titanium alloy production technology,market prospects and industry development

Titanium alloy with a low density, high specific strength, corrosion resistance and good process performance, is the ideal structural materials for the aerospace engineering. Based on the microstructure of titanium alloys, it can be divided into α-type titanium alloys (heat-resistant titanium alloys), β-type titanium alloys and α + β-type titanium alloys. The research scopes also include the fabrication technology of titanium alloys, powder metallurgy, rapid solidification technology, and other military and civilian applications of titanium alloys. Titanium and its alloys have become the ideal structural materials used for the fuselage, and accounted for a significant part of the structural quality in most military aircrafts. Titanium’s future market expectations need to be considered in the macro level market. Apart from the supply and demand trends of titanium market, it is necessary to consider the impact of technological innovations that can help to reduce the cost of titanium production.     

Influence of the degree of oxygen rarefaction in a medium on the interaction of boron carbide with titanium alloys

We describe the mechanism of processes at the metal-saturating medium interface in the course of thermodiffusion saturation of titanium in boron carbide at temperatures that do not exceed the point of polymorphic transformation of titanium alloys. We have established the influence of oxygen partial pressure over a layer of boron carbide on the character of interaction between the saturating medium and titanium. We show the possibility to form stable boride coatings on a titanium matrix. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 43, No. 1, pp. 80–84, January–February, 2007.     

Nucleation and growth kinetics of reaction-product formation for copper–titanium and silver–titanium alloys on alumina

A nucleation and growth mechanism is proposed for the formation of the reaction product at the interface between polycrystalline alumina and liquid-metal alloy drops containing titanium. The reaction product had been previously identified to be an oxide of titanium. The growth of reaction product islands was clearly observed at the alumina–metal interface using optical microscopy after dissolving the metal droplets with acid. The fractional coverage was quantified as a function of time and, by assuming Avrami-type reaction kinetics, surface reaction rate constants, k, were calculated for copper–titanium and silver–titanium alloys on alumina. Reaction rate constants between 1.4 × 10^-4 and 18 × 10^-4 s^-2 were obtained for copper–titanium alloys on alumina. The k values for silver–titanium alloys were found to be an order of magnitude lower (2.5 × 10^-6 and 7.2 × 10^-6 s^-2) then the k values obtained for copper–titanium alloys on alumina. This revised version was published online in November 2006 with corrections to the Cover Date.     

Corrosion and mechanical properties of titanium alloyed with aluminum, iron, and molybdenum

We study the influence of Fe, Al, and Mo on the corrosion and mechanical properties of titanium. It is shown that the corrosion resistance of titanium becomes 3.5 times lower as the concentration of iron increases from 0.1 to 5%. The microalloying of Ti-Al-Fe-Mo alloys with molybdenum inhibits corrosion. We develop new low-alloy structural and corrosion-resistant titanium alloys of the Ti-Al-Fe-Mo system. Their innovative character is confirmed by patents of the Ukraine. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 42, No. 5, pp. 41–44, September–October, 2006.     

Severe plastic deformation (SPD) and nanostructured materials by machining

Large plastic strains between 1 and 15 can be imposed in chips formed by plane-strain (2-D) machining of metals and alloys. This approach has been used to examine microstructure changes induced by large strain deformation in model systems—copper and its alloys, precipitation-hardenable aluminum alloys, high-strength materials such as titanium, Inconel 718 and 52100 steel, and an amorphous alloy. It is shown that materials with average grain sizes in the range of 60 nm–1 μm can be created by varying the parameters of machining, which in turn affects the deformation processes. Furthermore, a switch-over from an elongated subgrain microstructure to an equi-axed nanocrystalline microstructure, with a preponderance of large-angle grain boundaries, has been demonstrated at the higher levels of strain in several of these materials. This switch-over can be readily controlled by varying the deformation conditions. Dynamic recrystallization has been demonstrated in select material systems under particular conditions of strain and temperature. This study may be seen as providing an important bridge between furthering the understanding of microstructural refinement by large strain deformation and the practical utilization of nanostructured materials in structural and mechanical applications. Conventional plane-strain machining has been shown to be a viable SPD method for examining the underlying processes of very large strain deformation.     

Crystallization of titanium ingots in the course of electron-beam melting

Using mathematical models of the heat transfer processes in the course of ingot formation by electron-beam remelting, we determined the temperature conditions and the corresponding technological parameters under which a homogeneous structure without coarse columnar crystallites is reached in ingots of round and rectangular cross sections. A technology and equipment were developed for the production of large-scale ingots of titanium alloys up to 1200 mm in diameter and 4.5 m in length directly from uncrushed cakes of spongy titanium. The quality of ingots of both commercially pure and alloyed titanium meets the requirements of the ASTM B348-00 standard. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 44, No. 3, pp. 21–27, May–June, 2008.     

Basic trends of scientific research into the problem of titanium in the Ukraine

We analyze the state-of-the-art and prospects of the research into the development of physical and metallurgical foundations of creation of new alloys based on titanium and cost-efficient technologies of their production and treatment at the Ukrainian scientific-research institutions with an aim to improve their service properties and, hence, promote more extensive application of these unique structural materials. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 42, No. 3, pp. 5–16, May–June, 2006.     

Development of titanium alloys by the method of complex alloying

We study the effect of alloying on the mechanical properties of welded joints and base metal of titanium alloys of the system Ti-Al-Mo-V-Cr-Fe. We also formulate the theoretical aspects and principles of complex alloying of titanium alloys and the theory of alloying of additive materials for the welding of α-, (α + β), and β-alloys. It has been shown that (α + β)-(VT23) and β-(VT19) structural titanium alloys, developed on the basis of the proposed theory of complex alloying, provide high weight efficiency of construction of present-day flying vehicles. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 42, No. 5, pp. 45–50, September–October, 2006.     

Design and microstructural analysis of magnesium alloys for dynamical applications

A microanalytical characterization of cast magnesium alloys of eutectic origin based on the Mg–Al–Ca ternary matrix system has been carried out in order to investigate the influence of alloying elements on their microstructure as well as microchemistry-processing-microstructural relations using structure-sensitive techniques of electron microscopy, mechanical spectroscopy (internal friction), X-ray diffractometry, and advanced microanalytical methods including electron probe compositional analysis. Following the data obtained here there is direct correlation of microstructure with creep properties of the new experimental magnesium alloys. The creep and heat-induced properties of the multicomponent magnesium alloys containing low range of inexpensive additions of titanium (0.07–0.2%) or strontium (of about 1.8%) are defined by resulting structure dynamically formed during creep strain (up to 200 h). It is noteworthy that Ti as novel alloying element competes for creep resistance and cost with Sr and attracts as-cast desirable properties minimizing solute effects at ambient temperatures because of the pinning of slowly moving dislocations with the binding energy no more then 0.3 eV as well as because of stress-induced strengthening. The Ti and Sr solute atmosphere dragging is believed to be the rate-controlling mechanism responsible for radical improvement of creep resistance and long-term strength in the newly developed magnesium alloys at elevated temperatures. The new experimental alloys are superior to commercial alloys AZ91D, AE42, and AS21 following their creep resistance, long-term strength, heat resistance, and castability because of their novel microstructure having desirable engineering properties for structural applications (creep strain ε_c less than 0.3–0.4% at 423 K and 70 MPa for 200 h; έ_c ~ 10⁻⁹ s⁻¹). The newly developed magnesium alloys with improved castability could be used in die-casting technology and automobile (powertrain) industry for manufacturing of components and parts which are difficult to cast with more desirable microstructure.     

Corrosion of titanium alloys in aqueous solutions of hydrochloric acid

We investigate the kinetics of corrosion of α-, (α+β)-, and β-titanium alloys in aqueous solutions of hydrochloric acid. It is shown that the process of dissolution obeys a parabolic law and is accompanied by the formation of an oxide (TiO₂ rutile) film on the metal surface. We demonstrate that corrosion processes are intensified as the amount of the β-phase in titanium alloy increases. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 33, No. 3, pp. 112–115, May–June, 1997.     

2010年中国钛工业发展报告(英文)

回顾了2010年中国钛工业的运行情况,介绍了中国钛工业的生产和进出口情况,分析了海绵钛和钛加工材的价格走势。2010年中国钛工业呈明显回升状态,海绵钛产能突破10万t,产量达到57770t,与2009年相比增长41.6%;钛加工材产量达到38323t,与2009年相比增长53.5%。2010年,中国化工、航空航天、冶金、真空制盐等行业用钛大幅增长,从而使中国钛制品的销售量达到创记录的35636t。特别是化工用钛量已近2万t,成为中国用钛的绝对第一大领域。应更好地把钛材的应用推广工作做好,迎来行业的更大发展。     

TiAl合金表面涂层技术研究现状

TiAl合金由于其密度低,比强度和比刚度高,是航空航天工业理想的新型高温结构材料.室温塑性差的问题已通过添加合金元素和显微组织调控等手段基本得到解决,进一步提高其高温抗氧化和耐磨性能已成为需要重点研究的问题.表面涂层技术为这一问题的解决提供了一条有效的途径,为此,综述了国内外TiAl合金表面涂层技术的研究现状,重点介绍了激光技术和热喷涂技术及其应用,并展望了TiAl合金表面涂层技术的发展趋势.     

Microstructure and grindability of as-cast Ti–Sn alloys

In this study, the structure, microhardness, and grindability of a series of binary Ti–Sn alloys with tin contents ranging from 1 to 30 wt% were investigated. Commercially pure titanium (c.p. Ti) was used as a control. The experimental results indicated that all the Ti–Sn alloys showed hcp α structure, and the hardness values of the Ti–Sn alloys increased with greater Sn contents, ranging from 246 HV (Ti–1Sn) to 357 HV (Ti–30Sn). Among these Ti–Sn alloys, the alloy with 30 wt% Sn content showed the highest hardness value. The grindability of each metal was found to be largely dependent on the grinding conditions. The addition of Sn to c.p. Ti did contribute to improving the grindability of c.p. Ti. The Ti–Sn alloys with a higher Sn concentration could be ground more readily. The grinding rate of the Ti–20Sn alloy at 1200 m/min was about 2.8 times higher than that of c.p. Ti. Additionally, the grinding ratios of the Ti–10Sn, Ti–20Sn, and Ti–30Sn alloys at 1200 m/min were about 2.8, 2.7, and 3.4 times that of c.p. Ti, respectively. Our research suggests that the Ti–Sn alloys with Sn contents of 10 wt% and greater developed here are good candidates for machining by the CAD/CAM method.     

航空发动机钛燃烧及阻燃钛合金

介绍了航空发动机钛燃烧事故，以及钛合金燃烧试验，阻燃性能测试方法和太合金在国内外的研究和应用，并对国内外后的发展提出了一些建议。