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Burning products of TA15 titanium alloy by friction oxygen concentration method

Rare Metals 2018年第11期37卷 952-960页

作者： Nan Sui Guang-Bao Mi Meng-Qi Yan Jing-Xia Cao Xu Huang Aviation Key Laboratory of Science and Technology on Advanced titanium alloys AECC Beijing Institute of Aeronautical Materials

The microstructural characteristics, elemental distribution law and microscopic formation mechanism of the burning products of TA15 titanium alloy were investigated by friction oxygen concentration method, associated with in situ observation, X-ray diffraction(XRD),scanning electron microscopy(SEM) and energy-dispersive spectroscopy(EDS) analyses, providing the thoughts to improve fireproof property. The results show that, when the friction contact pressure(p) is 0.20 MPa and oxygen concentration of premixed air flow(c) is 60 vol%, TA15 titanium alloy produces violent sparks and presents dazzling white light during combustion. The generated products after burning are mainly TiOand small amount of AlOoxides. Four distinct zones form from the combustion surface to the alloy matrix, and they are in the sequence of combustion zone, fusion zone, heat-affected zone and transition zone. Further, combustion zone is composed of TiOand A1203 compounds, containing obvious cracks. In the fusion zone, discontinuous oxygenrich Al-based solid solution forms, and the elemental distribution has strong volatility. In the heat-affected zone,there are abundant of Ti-based solid solution and small amount of Al-and Mo-based solid solution. Transition zone is made of lamellar structure. Two technical approaches are given to prevent oxygen diffusion inside the reaction zone and reaction-affected zone. On the one hand,the content of Al is designed as the upper limit of alloy composition; on the other hand, fireproof coatings are deposited on the surface of the alloy.

关键词： Friction oxygen concentration method TA15 titanium alloy Burning products Microstructure titanium fire

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Effect of size and distribution of titanium carbide on microstructure and mechanical properties of Ti-25V-15Cr-2Al-0.2C-0.2Si alloy

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中国有色金属学会会刊：英文版 2005年第4期15卷 722-726页

作者：雷力明黄旭王宝赵红霞曹春晓 D.Rugg W.Voice Laboratory of titanium alloys Beijing Institute of Aeronautical Materials Rolls-Royce Plc P.O.Box 31

The effect of size and distribution of titanium carbide on the microstructure and mechanical properties of non-burning β titanium alloy Ti-25V-15Cr-2Al-0.2C-0.2Si (mass fraction, %) was investigated. The microstructure of the heat-treated and exposed alloy was studied using optical microscopy(OM), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). It is found that carbides with finer size and more uniform distribution can suppress the formation of α precipitates more effectively, and can especially decrease the amount of grain boundary α precipitates after long-term exposure at 540℃ (the expected application temperature). Thus, significant improvement in thermal stability can be achieved by refining carbide particles in the matrix of the alloy.

关键词：二氧化钛微结构合金热处理

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Nanoindentation and Wear Characteristics of Al 5083/SiC_p Nanocomposites Synthesized by High Energy Ball Milling and Spark Plasma Sintering

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Journal of Materials Science & Technology 2012年第11期28卷 969-975页

作者： Sivaiah Bathula Saravanan M Ajay Dhar Metals and alloys Group Materials Physics and Engineering Division CSIR-National Physical Laboratory

AI 5083//10 wt% SiCp nano composites have been synthesized by means of high energy ball milling followed by spark plasma sintering （SPS）. Nano composites produced via this method exhibited near-theoretical density while retaining the nano-grained features. X-ray diffraction （XRD） analysis indicated that the crystalline size of the ball milled AI 5083 matrix was observed to be～25 nm and it was coarsened up to～30 nm after SPS. Nano indentation results of nano composites demonstrated a high hardness of～280 HV with an elastic modulus of 126 GPa. Wear and friction characteristics with addition of SiCp reinforcement exhibited significant improvement in terms of coefficient of friction and specific wear rate to that of nano structured AI 5083 alloy. The reduction in specific wear rate in the nanocomposite was mainly due to the change of wear mechanism from adhesive to abrasive wear with the addition of SiCp which resulted in high hardness associated with nano-grained microstructure.

关键词： Metal matrix nano composites Friction/wear Mechanical properties Highresolution transmission electron microscopy Spark plasma sintering Nanoindentation

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Characteristic of Local Boiling Heat Transfer of Ammonia and Ammonia/Water Binary Mixture on the Plate Type Evaporator

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Journal of Thermal Science 2011年第4期20卷 332-342页

作者： Akio OKAMOTO Hirofumi ARIMA Yasuyuki IKEGAMI titanium division KOBE STEEL Ltd.Japan Institute of Ocean Energy Saga UniversityJapan

Power generation using small temperature difference such as ocean thermal energy conversion(OTEC)and discharged thermal energy conversion(DTEC)is expected to be the countermeasures against global warming *** ammonia and ammonia/water are used in evaporators for OTEC and DTEC as working fluids,the research of their local boiling heat transfer is important for improvement of the power generation *** of local boiling heat transfer coefficients were performed for ammonia/water mixture(z=0.9-1)on a vertical flat plate heat exchanger in a range of mass flux(7.5-15 kg/m2s),heat flux(15-23 kW/m 2),and pressure(0.7-0.9 MPa).The result shows that in the case of ammonia/water mixture,the local heat transfer coefficients increase with an increase of mass flux and composition of ammonia,and decrease with an increase of heat flux.

关键词： Local Heat Transfer Ammonia/Water Mixture Plate Type Evaporator OTEC

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Interactions between dislocations and twins in deformed titanium aluminide crystals

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Journal of Materials Science & Technology 2019年第3期35卷 402-408页

作者： Guang Yang Shang-Yi Ma Kui Du Dong-Sheng Xu Sen Chen Yang Qi Heng-Qiang Ye School of Materials Science and Engineering Northeastern University Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences division of titanium alloys Institute of Metal Research Chinese Academy of Sciences Department of Materials Physics and Chemistry School of Materials Science and Engineering Northeastern University

Using scanning, transmission electron microscopy and aberration-corrected scanning transmission electron microscopy, we have studied the interactions between dislocations and twins in impact deformed polysynthetic twinned TiAl crystal. The 1/3 dislocations with the coherent twin *** abnormal stacking fault was found adjacent to the coherent twin boundary. It has the same stacking sequence but different atom species in the [110] direction with an additional displacement of 1/4[110]in two neighboring {111} layers, and is likely induced by the slip of a 1/12[112](i.e. 1/4[110] + 1/6[211])dislocation.

关键词： TiAl Dynamic deformation Twins Dislocations Abnormal stacking fault

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Superelastic metastable Ti-Mo-Sn alloys with high elastic admissible strain for potential bio-implant applications

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Journal of Materials Science & Technology 2023年第32期163卷 45-58页

作者： Shuanglei Li Jae H.Kim Seung Won Kang Jae Ho Kim Tae-Hyun Nam Jong-Taek Yeom titanium alloys Department Metal Materials DivisionKorea Institute of Materials Science(KIMS)Changwon 51508Republic of Korea Department of Materials Engineering and Convergence Technology&Research Institute for Green Energy Convergence Technology(RIGET) Gyeongsang National University900 GazwadongJinjuGyeongnam 52828Republic of Korea

The demand for titanium alloys simultaneously having high elastic admissible strain and large recovery strain for bio-implant applications is ***-free Ti-based shape memory alloys are promising candidates for obtaining the required multifunctional *** this study,a wide content range of(0-15)wt%of low-cost,toxicity-free,and high-biocompatible Sn element was added to the Ti-8Mo(wt%)alloy to study its effect on the superelastic recovery and mechanical properties of biomedical Ti-Mo-Sn *** tailoring Sn content,desired multifunctional properties of high elastic admissible strain and room temperature superelasticity were achieved in the studied Ti-Mo-Sn *** was found that the increase in Sn content stabilized theβphase and a singleβphase was obtained at room temperature in Ti-8Mo-(13,15)Sn *** addition of Sn modified the lattice parameters of theα″martensite andβphase and affected the lattice deformation stain ofβ→α″.The lattice deformation strain along the[011]βdirection was found to be decreased by-0.26%/wt%*** room temperature superelasticity with a recovery strain of 3.1%and an elastic admissible strain of 1%was obtained in the Ti-8Mo-13Sn *** Sn content increased to 15 wt%,a high elastic admissible strain of 1.56%and a recovery strain of 2.0%were *** Ti-Mo-Sn alloys with excellent multifunctional properties are promising candidates for bio-implant applications.

关键词： Ti-Mo-Sn alloy Shape memory alloy Elastic admissible strain Elastic modulus Superelasticity

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Hierarchical structure and deformation behavior of a novel multicomponent β titanium alloy with ultrahigh strength

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Journal of Materials Science & Technology 2022年第12期107卷 227-242页

作者： X.Li X.N.Wang K.Liu G.H.Cao M.B.Li Z.S.Zhu S.J.Wu School of Materials Science and Engineering Beihang UniversityBeijing 100191China titanium alloys Laboratory Beijing Institute of Aeronautical MaterialBeijing 100095China School of Materials Science and Engineering Shanghai UniversityShanghai 200444China

Based on the general [Mo] equivalent criterion and d-electron orbital theory, a new ultrahigh-strength βtitanium alloy with eight major elements(Ti-4.5Al-6.5Mo-2Cr-2.6Nb-2Zr-2Sn-1V, TB17) for industrial applications was developed. An ingot of five tons was successfully melted by thrice vacuum consumable arc melting. The microstructure and elements partitioning of different conditions were investigated systematically. The results suggest that the hierarchical structures of micro-scale first α phase(αf), nano-scale secondary α phase(αs), and ultrafine FCC substructures can be tailored by solution plus aging(STA) heat treatment. The lateral and epitaxial growth of αfphase promotes the HCP-α to FCC substructure transformation with the help of elements partitioning during the aging process. Moreover, the element V, generally regarded as β stabilizer, is found to mainly concentrate in the Al-rich αfphase in this study probably due to its relatively lower content and the strong bonding energy of Al-V. The hierarchical structure has a strong interaction with dislocations, which contributes to achieve a superhigh strength of 1376 *** addition, the plastic strain is partitioned in the multi-scale precipitates(such as the α and FCC substructures) and β matrix, resulting in a considerable plasticity. TEM observation demonstrates that high density entangled dislocations at interfaces and mechanical twins exist in the STA sample after tensile test. It can be deduced that both dislocation slipping and twinning mechanisms are present in this ***, TB17 alloy can serve as an excellent candidate for structural materials on aircrafts that require high strength and lightweight.

关键词： titanium alloy Hierarchical structure Deformation behavior Ultrahigh strength Elements partitioning

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Heat treatment process for improving ductility of Ti-25V-15Cr-2Al-0.2C alloy

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中国有色金属学会会刊：英文版 2003年第5期13卷 1175-1180页

作者：雷力明黄旭孙福生吴学仁曹春晓 D Rugg W Voice Laboratory of titanium alloys Beijing Institute of Aeronautical Materials Beijing 100095China Rolls Royce Plc P.O. Box31 Derby DE24 8BJ UK

The effect of heat treatment and thermal exposure on the microstructure and mechanical properties of non burning β titanium alloy Ti 25V 15Cr 2Al 0.2C (mass fraction, %) was investigated. It is found that the amount of α precipitation in samples after solution treatment followed by air cooling increases with increasing solution temperature. After solution treatment, the alloy was subjected to two different heat treatments to stabilize the material. The results show that the single ageing treatment(700 ℃, 4 h, AC) leads to a large amount of α precipitation, while the triplex treatment(850 ℃, 2 h, FC+700 ℃, 6 h, FC+540 ℃, 6 h, AC) significantly suppresses the formation of α precipitates. It is more important that after long term exposure at 540 ℃(the expected application temperature) samples heat treated by the triplex treatment have markedly higher ductility than those given the single aging treatment. The intermetallic compound TiCr 2 is observed in samples after long term exposure, which further degrades the ductility of the alloy.

关键词：热处理延展性 Ti-25V-15Cr-2Al-0.2C合金钛合金机械性能

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Creep Behavior of Fusion Zone and Base Metal of the Electron Beam Weldments of a Near-alpha titanium Alloy

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Journal of Materials Science & Technology 2010年第6期26卷 564-571页

作者： Zhiyong Chen Jinwei Li Jie Liu Qingjiang Wang Jianrong Liu Rui Fang division of titanium alloys Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Research Department of High Energy Density Beam Processing Technology Beijing Aeronautical Manufacturing Technology Research Institute Beijing 100024 China AVIC Shenyang Liming Aero-engine (Group) Corporation LTD Shenyang 110043 China

The high temperature creep behavior of fusion zone （FZ） and of a near-alpha titanium alloy Ti-60 has been investigated. base metal （BM） of the electron beam weldments While the BM shows a fully transformed, coarse primary β grains with large colonies consisting of aligned α lamellar, the FZ exhibits thin martensitic α′ platelets in the columnar β grains. The creep results show that the steady state creep rates of FZ follow the power-law creep, with the stress exponents obtained in the range from 5.6 （550℃） to 5.9 （600℃）, and corrected activation energies of 309-352 kJ/mol; the stress exponents of BM exhibit different values when the creep testing stress and temperature alternate. The values of 2.4-3.2 are obtained when the stresses are under 220 MPa or the temperature is 550℃, also an exponent of 6.6 is achieved at stresses above 220 MPa at 600℃. The corrected activation energies of BM corresponding to the stress exponents are 123-161 kJ/mol （n=2.4-3.2） and 344 kJ/mol （n=6.6）. The creep mechanisms of FZ and BM have been discussed in light of the creep microstructures, activation energies and the stress exponents. The creep mechanisms of FZ is the diffusion controlled dislocation climb, the creep of BM is controlled by ＇solute drag＇ creep and dislocation climb when the stress and temperature are different. Transmission electron microscopy （TEM） observations of the dislocation structures of crept specimens are presented to give some supports for the creep behavior of FZ and BM. In addition to the creep mechanism of dislocation movement, the interface sliding has been found to play an important role during creep of FZ.

关键词： Steady state creep Stress exponent Activation energy Electron beam welding Near-alpha titanium alloy

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Surface Temperature Field of Ti-66Al and Ti-Al and Ti-4848Al alloysAl alloys Under Continuous Laser AblationUnder Continuous Laser Ablation

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稀有金属材料与工程 2024年第9期53卷 2405-2412页

作者： Sun Ruochen Mi Guangbao Aviation Key Laboratory of Science and Technology on Advanced titanium alloys AECC Beijing Institute of Aeronautical MaterialsBeijing 100095China

The high temperature fire retardancy of titanium alloy is an important factor restricting its application in aero-engine,and the laser ignition method can accurately reflect the fire retardancy of titanium alloy under local *** to the limitations of laser ignition experiments on the microscopic boundary and the transient propagation mechanism of the temperature field,molecular dynamics(MD)simulations and JMatPro calculation were applied to study the temperature field of Ti-6Al and Ti-48Al *** results show that a molten pool is formed on the surface of Ti-Al alloys under continuous laser irradiation,and the temperature field of the molten pool is normally distributed from the center to the *** the center temperature reaches the critical point of ignition,the extended combustion occurs,and the extended combustion path advances along the direction of the air *** with Ti-6Al alloy,Ti-48Al alloy has higher fire retardancy under laser *** is due to the better heat transfer performance of Ti-48Al,which leads to the weakening of the heat concentration effect near the boundary of the spot temperature *** it is necessary to increase the partial pressure of oxygen,and thus to reduce the ignition point of the alloy in order to achieve the ignition boundary condition of Ti-48Al alloy under the same laser heat *** the aspect of extended combustion path,the boundary heat collection effect of specimens shown by MD models reveals another mechanism affecting combustion expansion path besides the direction of air *** is,the heat generated by the laser spot is interrupted when it is transmitted to the boundary of the specimen along the short side direction,resulting in a concentration of heat near the *** the combustion path also tends to expand along this direction.

关键词： Ti-Al alloys laser ignition molecular dynamics temperature field

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