固溶时效处理对Ti-6Al-4V ELI钛合金准静态和动态力学性能的影响

采用万能力学试验机及霍普金森压杆试验研究了固溶和时效处理对Ti-6Al-4V ELI钛合金准静态拉伸性能和动态压缩性能的影响。结果表明,Ti-6Al-4V ELI钛合金经固溶时效处理后(固溶温度941 ℃),其屈服强度可达1097 MPa以上,抗拉强度可达1167 MPa以上。相比热处理前的Ti-6Al-4V ELI钛合金,强度显著提升,而且塑性指标也维持在较高水平。同时,不同应变速率下Ti-6Al-4V ELI钛合金的动态压缩性能提升明显,动态压缩强度和应变速率的对数呈线性关系,且随着应变速率的增加而增大。     

影响外科植入螺钉用钛合金棒材扭转性能的因素

为了使钛合金棒材在外科植入螺钉中得到应用,以普通ψ6.0 mm TC4ELI钛合金棒材为例,对其生产过程进行了不同工艺试验,研究了材料的力学性能、显微组织与扭转性能。结果表明:经不同工艺试验的钛合金平均晶粒尺寸为4~5μm,扭转性能较普通钛合金棒材显著增加,最大扭转角提高31.2%~32.7%,可达到180°以上。相同规格棒材抗拉强度越高,扭转性能就低。同时发现TC20钛合金棒材的扭转性能优于TC4ELI棒材,应与其合金元素有关。     

TC4ELI钛合金的电子束冷床熔炼技术

采用EBCHR-3150KW大功率电子束冷床熔炼炉，研究了以“TA1纯钛残料+海绵钛+中间合金”通过一次EB熔炼TC4ELI钛合金扁锭的生产工艺，分析了熔炼工艺参数对铸锭化学成分的影响，并对工艺可行性进行了分析，研究了不同热处理制度对板材组织性能的影响。结果表明：TC4ELI钛合金EB熔炼过程中Al元素的实际挥发率达到15%～18%,通过控制原材料制备使其达到宏观均匀、控制成分配比，制定合理的工艺要求，完全可以生产出符合国标GB/T 3620.1-2016要求的TC4ELI钛合金EB扁锭。     

锻造工艺对TA7ELI钛合金组织和力学性能的影响

研究了不同锻造工艺对TA7ELI钛合金锻件显微组织和力学性能的影响。结果表明,超低温伸长率最高的锻造工艺不是室温塑性最好的工艺,而是室温塑性最差的工艺。不同工艺锻造的TA7ELI钛合金锻件室温力学性能和超低温力学性能各具优缺点,实际生产中可根据产品侧重的性能要求选择相应的锻造工艺。     

TC4ELI钛合金低周疲劳性能研究

研究了具有网篮组织的TC4ELI钛合金材料在不同应变幅值下的低周疲劳性能,给出了TC4ELI钛合金在低周疲劳下的循环应力-应变曲线,拟合出循环应变硬化指数、循环强度系数以及应变-寿命特征系数,并通过光学显微镜进行金相分析,通过扫描电镜进行断口形貌分析。结果表明,TC4ELI钛合金呈现出循环软化的特性;距离疲劳断口1.5 mm处的组织形态与断口处无明显变化,疲劳裂纹以穿晶方式扩展直至断裂;随着应变幅值增大,韧窝变大变深,韧性断裂特征变得更加显著。     

TA15ELI显微组织及损伤容限性能研究

采用一火β区热轧和一火两相区上部温度热轧获得了片状组织的TA15ELI钛合金厚板，通过两相区900℃、930℃、950℃和β区980℃退火热处理进一步调整合金显微组织和损伤容限性能，测定了不同热处理状态下合金的显微组织特征参数和室温拉伸性能、断裂韧性、疲劳裂纹扩展速率，分析了显微组织对损伤容限性能的影响关系。研究发现：两相区退火，随着退火温度的升高，TA15ELI钛合金组织中初始β晶粒尺寸和α集束尺寸基本不变，α片平均厚度有所增加，合金强度和塑性均有所下降，da／dN降低，KIC提高；合金在β区980℃退火较两相区退火具有更好的损伤容限性能和综合性能。     

低温钛合金的研究进展

因具有优异的低温综合性能,钛合金作为重要的低温工程材料而逐渐受到广泛重视。本文概述了当前国际低温钛合金的应用现状,从α钛合金、α/β两相钛合金及β钛合金方面,综述了钛合金低温变形机制的最新研究进展,并总结了这3类不同相成分的钛合金的低温变形机制。从温度、合金成分、形变因素和显微组织方面,归纳总结了不同因素对钛合金低温塑性变形机制的影响。另外,还探讨了低温钛合金的发展趋势,以期为新型综合性能更好的低温钛合金的设计和研发提供参考。     

固溶温度对TC4ELI钛合金组织和性能的影响

研究了固溶温度对TC4ELI钛合金的组织和性能的影响.结果表明,随固溶温度的升高,TC4ELI钛合金中等轴α组织的数量减少,而β转变组织的数量逐渐增加.其抗拉强度、屈服强度和断裂韧性随固溶温度的升高而上升,断面收缩率和伸长率下降,特别是断面收缩率下降幅度较大;另外抵抗裂纹扩展的能力也逐渐增强.     

石油领域耐蚀钛合金电化学特性与选材研究

针对石油工业领域钛合金油井管选材困难的问题，本文以当前市场内较常规的四类钛及钛合金TA2(工业纯钛)、TA10(Ti-0.3Mo-0.8Ni)、TC4(Ti-6Al-4V)、TC4ELI(Ti-6Al-4VELI)为研究对象，利用腐蚀电化学原理分别在常温与加热状态下对上述材料进行耐蚀性能评估，腐蚀环境模拟油田井下含CO₂-H₂S-Cl^--H₂O工况。研究结果表明：常温状态下，耐蚀性能TA2最优，TC4次优，TC4ELI再次优，TA10则相对较弱；当腐蚀环境温度升高时，材料耐蚀参数较常温状态均有所降低，同时其强弱顺序与常温状态也有所不同，依据各参数可确定耐蚀能力由强到弱依次为TC4ELI、TA2、TC4、TA10。试验结果可为油井管选材提供相应理论支持。     

TC4-DT损伤容限型钛合金疲劳裂纹扩展特性的研究

研究了典型的损伤容限型钛合金Ti-6A1-4V ELI（TC4-DT）的断裂韧度KIC、疲劳裂纹扩展速率da／dN以及疲劳门槛值△Kth等损伤容限性能与微观组织的关系，讨论了不同应力比（尺值）条件下片状组织与双态组织的疲劳裂纹扩展特性，并与Ti-6A1-4V（TC4）钛合金进行了比较分析。研究结果为高损伤容限型钛合金的微观组织设计和探讨微观组织对损伤容限性能的影响机理奠定了基础。     

航空用损伤容限型钛合金研究与应用

为了满足新型飞机的大尺寸、高减重、长寿命和低成本的设计与应用需求,采用损伤容限型钛合金材料及其应用技术是一条重要途径。国外发达国家已经在新型损伤容限型钛合金材料研制和在先进飞机上的应用方面走在了前列,特别是像中强度的Ti-6Al—4VELI和高强度的Ti一6—22—22S等,已经成功地应用在了美国F-22／F-35,C-17等新一代飞机中,大大地提高了飞机的使用寿命和战斗力。这几年我国先后自主创新发展了中强度损伤容限型钛合金TC4-DT和高强度损伤容限型钛合金TC21,建立了损伤容限型钛合金的口处理加工技术,为我国新型飞机的研制奠定了材料应用技术基础。通过分析国内外损伤容限型钛合金材料及其新型加工工艺技术的研究发展情况,结合我国新型损伤容限型钛合金材料研究进展,重点探讨了新型损伤容限型钛合金的材料特点、性能水平和应用前景。     

Recent Progress in Titanium

A survey of the titanium alloys of greatest commercial significance and those in the pilot stage of development is presented. The alloys discussed include the alpha, alpha-beta, and all-beta titanium alloys. The properties and applications of these alloys are discussed with particular emphasis on their use in rocket motor cases. Other applications for titanium alloys including aircraft fasteners, air-frames, cryogenic vessels, and chemical processing equipment are also discussed. Speculation as to the future of the titanium industry is made.     

Influence of thermo hydrogen treatment on microstructure and mechanical properties of Ti-5Al-2.5Sn ELI alloy

Thermo hydrogen treatment(THT) of titanium is a process in which hydrogen is used as a temporary alloying element in titanium alloys. It is an attractive approach for controlling the microstructure and thereby improving the final mechanical properties. In the present study, the microstructure of the original(non-hydrogenated) sample has only α phase and the grains is coarse with an average size of ~ 650 μm. While the grain size of thermo hydrogen treated Ti-5Al-2.5Sn ELI alloy became finer and the mechanical properties were improved significantly. When the hydrogen content of the hydrogenated Ti-5Al-2.5Sn ELI alloy is 0.321 wt.%, β phase and δ titanium hydride appear. Also the average grain size decreases to 450 μm. When the hydrogen content is 0.515 wt.%, the grain size decreases to 220 μm. The mechanical properties were tested after dehydrogenation, and the mechanical properties improved significantly compared to the unhydrogenated specimens. The tensile strength of the Ti-5Al-2.5Sn ELI alloy improved by 17.7% when the hydrogen content increased to 0.920 wt.%, at the same time the percentage reduction of area(Z) increased by 33% and the impact toughness increased by 37%.     

Dynamic stress–strain properties of Ti–Al–V titanium alloys with various element contents

A series of Ti–Al–V titanium alloy bars with nominal composition Ti–7Al–5V ELI,Ti–5Al–3V ELI,commercial Ti–6Al–4V ELI and commercial Ti–6Al–4V were prepared.These alloys were then heat treated to obtain bimodal or equiaxed microstructures with various contents of primary a phase.Dynamic compression properties of the alloys above were studied by split Hopkinson pressure bar system at strain rates from 2,000 to 4,000 s-1.The results show that Ti–6Al–4V alloy with equiaxed primary a(ap)volume fraction of 45 vol%or 67 vol%exhibits good dynamic properties with high dynamic strength and absorbed energy,as well as an acceptable dynamic plasticity.However,all the Ti53ELI specimens and Ti64ELI specimens with ap of 65 vol%were not fractured at a strain rate of4,000 s-1.It appears that the undamaged specimens still have load-bearing capability.Dynamic strength of Ti–Al–V alloy can be improved as the contents of elements Al,V,Fe,and O increase,while dynamic strain is not sensitive to the composition in the appropriate range.The effects of primary alpha volume fraction on the dynamic properties are dependent on the compositions of Ti–Al–V alloys.     

Kupfer-, Nickel- und Titanlegierungen für Seewasseranwendungen

Copper and nickel alloys and titanium for seawater applications Copper and nickel alloys and titanium have been successfully used for heat exchangers on ships. In power plants and for chemical apparatus and piping systems because of their resistance against corrosion in sea water. Aluminium brass and copper nickel alloys, the standard materials for condensers and coolers, however, may be attacked, the corrosion depending on water quality, water velocity, and structural conditions. The mechanisms of corrosion are discussed. Under severe conditions the use of titanium may be indecated. The use of nickel base alloys is advantageous at elevated temperatures, e. g. for chemical reactions and for evaporation processes. Examples are given for application and for prevention of corrosion.     

Evaluation of titanium alloy fabricated using electron beam melting system for dental applications

In recently advanced rapid prototyping and manufacturing methods, one additional process is to use an electron beam to fabricate metal objects by the layer by layer sintering and/or melting metal powder. This method is often called electron beam melting (EBM). This study examined the mechanical properties, the grindability and corrosion resistance of Ti-6Al-4V ELI (extra low interstitial) specimens which were fabricated by the electron beam melting (EBM) process. Dumbbell-shaped specimens and two kinds of plate specimens were prepared using the Ti-6Al-4V ELI powder in the EBM system. The yield strength, tensile strength, modulus of elasticity and percent elongation at a crosshead speed of 0.25 mm/min were tested. The Vickers hardness in interior structures was determined. Grindability was evaluated as volume loss (mm³) when the specimen was abraded using a SiC wheel at 1250 m/min for 1 min. Lastly, corrosion behavior was examined using the dynamic potentiostatic polarization technique in an artificial saliva at 37 °C. As controls, cast and commercial wrought alloys of Ti-6Al-4V ELI and commercially pure titanium (CP Ti) were evaluated. Cast specimens were prepared in a centrifugal casting machine using a MgO based mold. For the cast specimens, all the mechanical properties, grindability and corrosion characteristics were tested. On the other hand, for wrought specimens, only grindability and corrosion properties were tested. The yield and tensile strength of the as-fabricated Ti-6Al-4V ELI specimens without any additional metallurgical treatments were found to be 735 MPa and 775 MPa, respectively. The elongation was 2.3%. These values are well within many of precious and non-precious dental casting alloys.     

医用多孔金属的制备及其生物活化研究进展

医用多孔金属材料,特别是多孔钛及钛合金能够提供与人体骨组织相匹配的力学性能,并促进骨组织长人以提高其与骨的固定度,在人体硬组织修复与替换方面具有广泛的应用前景。重点围绕多孔钛及钛合金的制备方法及适用于其复杂孔隙结构的表面生物活化方法,综述了各种方法在多孔钛及钛合金上的应用现状。目前适用于多孔钛及钛合金制备的技术主要有粉末冶金法、钛纤维烧结法、自蔓延高温合成法、选区电子束熔化技术和选区激光熔化技术,适用于多孔钛及钛合金表面生物活化的技术主要有溶胶凝胶法、仿生矿化法、电化学沉积法和微弧氧化法。多孔钛及钛合金的力学相容性和表面生物活性需要同时满足临床要求,才能进一步扩大其在医学领域的应用范围。     

中国航空结构用新型钛合金研究

中国钛产业近几年来得到了快速发展，钛材产量已经位居世界第4位，但航空结构用钛合金产品（锻件和大棒材等半成品）只占10％左右，距离世界水平的50％差距甚远。所以，加强航空结构用新型钛合金材料技术及其应用研究，提高航空结构用钛合金的加工技术和应用水平，建立具有中国特色的航空结构用钛合金材料体系，是提高钛合金在航空工业用量的重要推动力和保障。本文从分析国内外钛合金产业结构特点出发，重点阐述航空结构用新型钛合金材料和新型热工艺技术的最新研究进展。     

钛合金表面激光熔覆的研究进展

钛合金具有优异的物理化学性能,其在航空航天行业中被广泛应用.但钛合金的低硬度和低耐磨性能使它的应用受到了限制.激光熔覆因其熔覆层与基体结合力强,无污染等优点成为钛合金表面改性研究热点之一.钛合金表面熔覆具有不同特性的熔覆材料来提高钛合金表面的相应性能.介绍国内外钛合金激光熔覆的研究现状和发展趋势.