粉末钛合金锻造技术研究进展

粉末钛合金锻造是将粉末冶金与精密锻造相结合而发展的一种近净成形工艺,在获得完全致密、高性能粉末钛合金构件方面具有广阔的应用前景。介绍了粉末钛合金锻造技术在改善粉末钛合金的组织和性能、高性能低成本粉末钛合金、医用钛合金、金属间化合物、钛基复合材料等方面的应用情况,分析了粉末钛合金锻造技术促进粉末钛合金运用和发展所取得的技术进步。     

粉末钛合金热等静压近净成形技术及发展现状

粉末钛合金热等静压(HIP)近净成形技术作为一种理想的钛合金构件制备工艺之一,可以通过整体近净成形产品来提高材料利用率,降低钛合金产品的生产成本和生产周期,因此越来越受到武器装备等军工领域的关注。自该工艺出现以来,材料学者从原材料粉末的制备、包套设计、近净成形过程到材料的后处理都做了系统的研究,以了解该工艺的技术原理和材料性能影响因素,进而获得更高性能的产品,并进一步降低生产成本。研究表明,原材料粉末和包套设计是影响粉末钛合金近净成形产品质量和成本最重要的两个因素。球形度高、流动性好的钛合金粉末具有好的填充性和高的松装密度,能增加产品的成形精度。与此同时,作为控制粉末冶金制品中组织结构、孔洞和杂质元素的关键因素,高质量钛合金粉末的使用还可以获得力学性能更加优异的产品,但此种粉末的价格较高,增加了粉末冶金的生产成本,所以高质量、低成本钛合金粉末的制备是钛合金粉末冶金未来发展的重要方向之一。包套作为钛合金HIP近净成形技术的主要成本构成之一,合适的材料选择和结构设计既可以提高产品的成形精度又可以改善产品的表面质量,而通过计算机仿真模拟技术来设计包套和模拟近净成形过程,可以进一步提高成形精度和降低构件的研发成本,因此计算机仿真模拟是钛合金HIP近净成形未来发展的重点。通过选择合适的原材料粉末、设计合理的成形包套以及精确控制的成形过程,目前HIP近净成形获得的钛合金构件显示出与锻件相当的力学性能,而成本相对铸锻件节约了1/3以上。近年来,粉末钛合金热等静压近净成形技术在国外的航空航天等军工领域都已经得到了广泛的应用,并显现出理想的减重和降低成本的效果;国内则主要以航天领域的应用为主,而对其疲劳性能的质疑是限制其在国内航空领域广泛应用的主要原因。本文对粉末钛合金HIP近净成形技术进行了全面综述,对工艺过程中的影响因素,粉末致密化过程、力学性能及其影响因素等分别进行了阐述,同时介绍了计算机仿真模拟技术在粉末钛合金HIP近净成形技术上的应用。最后对该技术在国内外的应用情况进行了简要总结,并展望了该技术未来的发展趋势。     

钛及钛合金粉末的注射成形

介绍了钛及钛合金粉末注射成形技术的发展、应用现状及制备工艺.指出了钛及钛合金粉末注射成形技术研究方向和扩大应用的途径是:①使用价格低廉的氢化脱氢粉和气体雾化粉混合得到的钛及钛合金粉作为注射成形的原料粉末;②开发新型高效的钛及钛合金粉末注射成形用的粘结剂体系;③优化混炼工艺;④优化注射条件参数以消除注射缺陷;⑤开发先进的脱脂工艺,使脱脂时间进一步缩短并减少脱脂缺陷,以降低成本;⑥研究钛及钛合金烧结工艺以及超小型零件的注射成形工艺,控制产品尺寸精度,提高产品性能,扩大产品的尺寸.     

粉末钛合金3D打印技术研究进展

粉末钛合金3D打印技术以低成本、易成形、柔性化制备、零件性能优异等优势,近年来成为钛合金近净成形制造领域的研究热点。总结了国内外粉末钛合金3D打印技术的研究进展,包括激光熔化沉积成形技术(LMD)、激光选区熔化成形技术(SLM)、电子束选区熔化成形技术(SEBM)。比较研究了3种成形技术制备的钛合金的组织特点及力学性能,并讨论了粉末钛合金3D打印技术的市场化现状与未来发展趋势。     

钛合金的应用现状及加工技术发展概况

钛合金具有密度小、强度高、耐高温和抗腐蚀性好等优点,在航空航天、船舶、汽车、医疗、化工和能源等领域获得了广泛的应用.首先从航空航天和非航空航天领域综述了钛合金的应用现状;然后从热处理、焊接性能和表面处理技术三个方面综述了钛合金加工工艺及性能;最后叙述了钛合金的最新成形技术,即超塑性成形技术、近净成形技术、激光成形制造技术及计算机模拟技术,并展望了钛合金的应用前景及发展方向.     

生物医用多孔钛及钛合金激光快速成形研究进展

多孔钛及钛合金具有良好的生物相容性和与人骨更匹配的力学性能,是人体理想的替代材料,因此其制备技术及相关性能研究引起了广泛关注。激光快速成形是一项先进的制造技术,在制备生物多孔金属材料时具有独特的优势。介绍了激光快速成形的工作原理和技术特征,根据成形工艺特点简要回顾了4种代表性激光快速成形技术(选择性激光烧结、选择性激光熔化、激光近净成形和激光立体成形)的国内外发展现状,并重点论述了这几种技术在制备生物医用多孔钛及钛合金方面的最新研究进展,最后指出了今后在该领域的主要研究工作。     

凝胶注模成形Ti6Al4V钛合金的组织和性能研究

目的 为了实现低成本、低能耗、高效率制备大尺寸复杂形状钛合金的问题,以凝胶注模技术为成形手段,制备近净成形Ti6Al4V合金,并研究其组织及性能.方法 通过溶液包覆法,在Ti6Al4V钛合金球形粉末表面包覆石蜡(PW),分析有机包覆层在凝胶注模过程中的作用机制及流变行为的影响,测定包覆前后不同粉末进行凝胶注模烧结后的组...     

钛合金HIP近净成形技术在航天上的应用

介绍了钛合金热等静压(HIP)近净成形的工艺特点及其在国内外航天领域的应用情况.与锻造、精密铸造、机械加工等传统成形方法相比,HIP近净成形钛合金综合力学性能高,节约原材料、成形周期短.由于产品的综合力学性能高、尺寸精度可控性好,HIP近净成形技术非常适合异型结构件特别是含空间曲面结构件的精密成形.     

钛粉末及其粉末冶金制品的发展现状

简要介绍了钛粉末的不同制备技术及特点。详述了钛粉末冶金制品的主要成形技术和产品的生产现状和趋势。对近年来研究和产业领域都很关注的球形钛粉末的制备技术进行了概括,指出适合工业化推广应用的技术发展方向。并对钛粉末冶金制品新的制备技术及其在汽车工业、医疗及生物等方面的应用研究作了总结。最后针对国内粉末冶金钛合金的市场发展和需求,讨论分析了国内钛粉末及其粉末冶金制品的研究热点、新的应用领域及今后所需解决的问题。     

电子束粉末床熔融制备钛铝基金属间化合物研究进展

钛铝基金属间化合物是一种理想的高温结构材料,但因存在室温塑性差、加工困难等不足而限制了其发展与应用。电子束粉末床熔融(Electron Beam Powder Bed Fusion, EB?PBF)技术能够实现近净成形,其加工中的低热应力特点适宜脆性材料的制备,是近年来广受关注的新型钛铝基金属间化合物成形方法。对用电子束粉末床熔融制备的钛铝基金属间化合物进行了介绍,并对近年来发表的以EB?PBF钛铝材料为研究对象的相关文献进行了综述。从工艺、后处理和性能表征等角度对目前的研究现状进行了分析总结,并对未来的研究工作提出了展望。     

医用钛基生物活性材料研究

医用钛基生物活性材料发挥了钛及其合金优异的力学性能,同时又具有良好的生物活性.评述了近年来国内外制备钛基生物活性材料的新技术和新方法,重点介绍了钛及其合金表面改性和钛基生物活性复合材料的研究现状,并对其发展进行了展望.     

Study of the properties of low-cost powder metallurgy titanium alloys by 430 stainless steel addition

Titanium is a lightweight metal with an outstanding combination of properties which make it the material of choice for many different applications. Nonetheless, its employment at industrial level is not widespread due to higher production costs with respect to competitor metals like steel and aluminium. In this work the production of low-cost titanium alloys is attempted by combining the utilisation of a powder metallurgy process and cheap alloying elements (i.e. commercial 430 stainless steel powder optimised for the powder metallurgy industry). Low-cost titanium alloys are fabricated by blending elemental titanium with stainless steel. The behaviour of the powders as well as that of the sintered materials are analysed and compared to that of a master alloy addition Ti6Al4V alloy. The produced low-cost titanium alloys show comparable properties to both wrought and powder metallurgy titanium alloys and, therefore, they are proposed as an alternative to obtain structural component made out of titanium alloys.     

电子束冷炉床熔炼(EBCHM)技术的发展与应用

本文系统总结了电子束冷炉床熔炼(Electron Beam Cold Hearth Melting-EBCHM)技术近四十年的发展脉络。详细介绍了电子束冷床炉熔炼的各主要方面,包括电子枪的改进,冷床炉结构演变和功能扩展以及消除钛合金冶金缺陷的独特优势、电子束冷床炉熔炼科学技术应用现状及当前的主要研究方向等。指出近年来EBCHM技术在钛及钛合金工业生产中的应用持续稳定增长,除了钛的废料回收,消除钛的冶金缺陷提高合金质量,满足航空发动机转动部件要求,是主要的推动因素。可为广大钛冶金、材料应用工作者和设计人员提供有价值的参考。     

Binary Zn-Ti alloys for orthopedic applications: Corrosion and degradation behaviors,friction and wear performance,and cytotoxicity

Zinc (Zn) and its biocompatible and biodegradable alloys have substantial potential for use in orthopedic implants.Nevertheless,pure Zn with a hexagonal close-packed crystal structure has only two independent slip systems,therefore exhibiting extremely low elongation and yield strength in its ascast condition,which restricts its clinical applications.In this study,as-cast Zn-xTi (titanium) (x =0.05,0.10,0.20,and 0.30 wt.％) binary alloys were hot-rolled and their microstructures,mechanical properties,wear resistance,and cytocompatibility were comprehensively investigated for orthopedic implant applications.The microstructures of both as-cast and hot-rolled Zn-xTi alloys consisted o fan α-Zn matrix phase and a TiZn16 phase,while Zn-0.2Ti and Zn-0.3Ti exhibited a finer α-Zn phase due to the grainrefining effect of Ti.The hot-rolled Zn-0.2Ti alloy exhibited the highest yield strength (144.5 MPa),ultimate strength (218.7 MPa),and elongation (54.2％) among all the Zn-xTi alloys.The corrosion resis-tance of Zn-xTi alloys in Hanks' solution decreased with increasing addition of Ti,and the hot-rolled Zn-0.3Ti alloy exhibited the highest corrosion rates of 432 μm/y as measured by electrochemical testing and 57.9 μm/y as measured by immersion testing.The as-cast Zn-xTi alloys showed lower wear losses than their hot-rolled counterparts.The extracts of hot-rolled Zn-xTi alloys at concentrations of ≤ 25％ showed no cytotoxicity to MG-63 osteosarcoma cells and the extracts of Zn-xTi alloys exhibited enhanced cytocompatibility with increasing Ti content.     

Oxidation‐Resistant Coatings for Application on High‐Temperature Titanium Alloys in Aeroengines

High‐temperature application of titanium alloys in aeroengines is often limited by their insufficient resistance to the aggressive environment. Magnetron‐sputtered Ti–Al based coatings were developed in order to increase the maximum service temperature of conventional titanium alloys from the present 520–600 °C, the temperature limit set by the mechanical capabilities of most advanced alloys. The coatings not only demonstrated excellent oxidation resistance but also demonstrated beneficial effects on mechanical properties. Most importantly, the fatigue behavior of the substrate alloys was not degraded, a major hurdle for coating application on titanium alloys so far. Initial results on Cr‐containing Ti–Al based coatings indicated significant potential for application on titanium aluminides.     

Phase transformation and microstructure control of Ti2AlNb-based alloys:A review

In recent years,the Ti2AlNb-based alloys are selected as potential alloys for elevated temperature appli-cations to replace conventional Ni-based superalloys owing to their good creep resistance and oxidation resistance which are related to the O precipitates.In this paper,the precipitation mechanisms of O phase,phase transformation and microstructure control of Ti2AlNb-based alloys are reviewed.Ti2AlNb-based alloys generally consist of B2/β,α2,and O phase with different morphologies which are derived from the various heat treatment processes,including equiaxed α2/O particles,bimodal microstructure,and Wid-mannst(a)tten B2/β + O structures etc.As a newly developed strengthening phase,O precipitates can be precipitated from the B2/β matrix or α2 phase directly as well as generated by means of peritectoid reac-tion ofα2 phase and bcc matrix.Microstructural control of the Ti2AlNb-based alloys can be implemented by refining the original B2/β grain size and regulating the O precipitates.Multidirectional isothermal forging (MIF) and powder metallurgy technique are two effective methods to refine the original B2/β grains and the morphology and size of O precipitates can be regulated by adding alloying components and pre-deformation process.Moreover,the phase diagram as well as coarsening behavior of Ti2AlNb-based alloys in ageing process is also reviewed.For the further application of these alloys,more emphasis should be paid on the deep interpolation of microstructure-property relationship and the adoption of advanced manufacturing technology.     

Synthesis and characterization of nano-crystalline CVD diamond film on pure titanium using Ar/CH4/H2 gas mixture

Titanium and Ti alloys have poor tribological properties and deposition of a well adherent diamond coating is a promising way to solve this problem. But diamond film deposition on pure titanium and Ti alloys is always difficult due to the high diffusion coefficient of carbon in Ti, the large mismatch in their thermal expansion coefficients, the complex nature of the interlayer formed during diamond deposition, and the difficulty of achieving very high nucleation density. A nano-crystalline diamond (NCD) film can resolve Ti and Ti alloys weak tribological performance due to its smooth surface. A well-adhered NCD film was successfully deposited on pure Ti substrate by using a microwave plasma assisted chemical vapor deposition (MWPCVD) system in the environment of Ar, CH₄ and H₂ gases at a moderate temperature. Detailed experimental results on the preparation, characterization and successful deposition of the NCD film on pure Ti are discussed.     

The effect of aluminum content on phase constitution and heat treatment behavior of Ti–Cr–Al alloys for healthcare application

As life expectancy steadily increases, developing reliable functional materials for healthcare applications gains importance. Titanium and its alloys, while attractive for such applications, are expensive. The present investigation suggests that it may be possible to reduce costs by using new, low-cost beta Ti alloys. To assess their reliability, the heat treatment behavior of beta Ti alloys, Ti–7 mass% Cr with varying Al content (0%, 1.5%, 3.0% and 4.5%), was investigated through electrical resistivity and Vickers hardness measurements. In the Ti–7Cr–0Al alloy quenched from 1173 K, only the beta phase was identified by X-ray diffraction (XRD). In Ti–7Cr–1.5 to 4.5 Al alloys, XRD detected both beta and orthorhombic martensite. On isochronal heat treatment behavior of Ti–7Cr–3.0, 4.5 Al alloys, resistivity at liquid nitrogen temperature and resistivity ratio increased between 423 and 523 K.These increases are due to reverse transformation of orthorhombic martensite to the metastable beta phase.     

Indentation behaviour and wear resistance of pseudoelastic Ti–Ni alloy

Abstract

Recent studies demonstrate that near equiatomic Ti–Ni alloys possess high resistance to surface damage by wear. It is suggested that the high wear resistance of Ti–Ni alloys is closely correlated to their pseudoelasticity, which is usually evaluated by tensile testing. However, when a Ti–Ni alloy is under wear, its surface is in a complex stress state. Since the thermoelastic martensitic transformation of Ti–Ni alloys responds differently to different stresses, it may not be appropriate to evaluate the pseudoelasticity by tensile testing. The present paper reports recent work on pseudoelastic behaviour of a Ti–51 at.-%Ni alloy employing a microindentation technique as well as tensile testing methods. In the present work, the wear performances of Ti–51 at.-%Ni alloy specimens with different degrees of pseudoelasticity were also investigated, and efforts were made to explain the beneficial effect of pseudoelasticity on the wear resistance of Ti–Ni alloys.     

生物材料中金属-陶瓷界面和微结构

本研究在钛合金表面施加与人体组织相容性极好的商业医用P-陶瓷（含Al₂O₃,SiO₂,K₂O,Na₂O等）涂层,在提高与人体组织相容性方面,收到了显著的效果．而在此之前,在钛合金表面上施加Si₃N₄涂层,由干有效地增强了钛合金与陶瓷涂层之间的结合强度;使效果更佳．这一复合涂层体系的成功,解决了目前遇到的问题,开创了不少新的应用领域．本研究不但给出复合涂层化学组成、工艺和性能,并且对其显微结构进行了深入地研究．