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钛合金Ti??6Al??4V车削加工表面硬化实验  [PDF]
哈尔滨工程大学学报 , 2013, DOI: 10.3969/j.issn.1006??7043. 201211021
Abstract: 针对钛合金Ti??6Al??4V加工表面硬化问题,通过不同切削参数下钛合金Ti??6Al??4V切削加工表面的显微硬度与微观结构检测实验研究,探索钛合金Ti??6Al??4V车削加工的表面硬化机理,分析切削参数对加工硬化与表面变质层影响规律.结果表明:进行钛合金Ti??6Al??4V车削加工时,表面层微观组织发生显著变化,但表面硬化程度不高,切削速度提高不会使表面硬化程度加剧,并有利于减少表面变质层的厚度;切削热对加工表面硬化的影响显著,切削温度升高将减弱表面层材料变形产生的应变硬化作用,表面变质层的显微硬度值低于亚表层的显微硬度值,但高于基体的显微硬度值.
Microstructure and Mechanical Behavior of Porous Ti–6Al–4V Processed by Spherical Powder Sintering  [PDF]
Lucía Reig,Concepción Tojal,David J. Busquets,Vicente Amigó
Materials , 2013, DOI: 10.3390/ma6104868
Abstract: Reducing the stiffness of titanium is an important issue to improve the behavior of this material when working together with bone, which can be achieved by generating a porous structure. The aim of this research was to analyze the porosity and mechanical behavior of Ti–6Al–4V porous samples developed by spherical powder sintering. Four different microsphere sizes were sintered at temperatures ranging from 1300 to 1400 °C for 2, 4 and 8 h. An open, interconnected porosity was obtained, with mean pore sizes ranging from 54.6 to 140 μm. The stiffness of the samples diminished by as much as 40% when compared to that of solid material and the mechanical properties were affected mainly by powder particles size. Bending strengths ranging from 48 to 320 MPa and compressive strengths from 51 to 255 MPa were obtained.
XPS study of the process of apatite formation on bioactive Ti–6Al–4V alloy in simulated body fluid
Hiroaki Takadama, Hyun-Min Kim, Tadashi Kokubo and Takashi Nakamura
Science and Technology of Advanced Materials , 2001,
Abstract: Bioactive Ti–6Al–4V alloy, which spontaneously forms a bonelike apatite layer on its surface in the body and bonds to living bone through this apatite layer, can be prepared by producing an amorphous sodium titanate on its surface by NaOH and heat treatments. In this study, the process of apatite formation on the bioactive Ti–6Al–4V alloy was investigated in vitro, by analyzing its surface with X-ray photoelectron spectroscopy as a function of soaking time in a simulated body fluid (SBF). Thin-film X-ray diffractometry of the alloy surface and atomic emission spectroscopy of the fluid were also performed complementarily. It was found that immediately after immersion in the SBF, the alloy exchanged Na+ ions from the surface sodium titanate with H3O+ ions in the fluid to form Ti-OH groups on its surface. The Ti-OH groups, immediately after their formation, incorporated the calcium ions in the fluid to form calcium titanate. The calcium titanate thereafter incorporated the phosphate ions in the fluid to form an amorphous calcium phosphate, which was later crystallized into bonelike apatite. This process of apatite formation on the alloy was the same as on the pure titanium metal, because the alloy formed the sodium titanate free of Al and V by the NaOH and heat treatments. The initial formation of the calcium titanate is proposed to be a consequence of the electrostatic interaction of negatively charged units of titania dissociated from the Ti-OH groups with the positively charged calcium ions in the fluid. The calcium titanate is postulated to gain a positive charge and interact with the negatively charged phosphate ions in the fluid to form amorphous calcium phosphate, which eventually stabilizes into crystalline apatite.
Interfacial microstructure and mechanical properties of Ti?6Al?4V/Al7050 joints fabricated using the insert molding method  [PDF]
Hong-xiang Li,Xin-yu Nie,Zan-bing He,Kang-ning Zhao,Qiang Du,Ji-shan Zhang,Lin-zhong Zhuang
- , 2017, DOI: https://doi.org/10.1007/s12613-017-1534-y
Abstract: Ti?6Al?4V/Al7050 joints were fabricated by a method of insert molding and corresponding interfacial microstructure and mechanical properties were investigated. The interfacial thickness was sensitive to holding temperature during the first stage, and a good metallurgical bonding interface with a thickness of about 90 μm can be obtained at 750°C. X-ray diffraction, transmission electron microscopy, and thermodynamic analyses showed that the interface mainly contained intermetallic compound TiAl3 and Al matrix. The joints featured good mechanical properties, i.e., shear strength of 154 MPa, tensile strength of 215 MPa, and compressive strength of 283 MPa, which are superior to those of joints fabricated by other methods. Coherent boundaries between Al/TiAl3 and TiAl3/Ti were confirmed to contribute to outstanding interfacial mechanical properties and also explained constant fracture occurrence in the Al matrix. Follow-up studies should focus on improving mechanical properties of the Al matrix by deformation and heat treatment.
Optimization of Bead Geometry in CO2 Laser Welding of Ti 6Al 4V Using Response Surface Methodology  [PDF]
Ali Khorram, Majid Ghoreishi, Mohammad Reza Soleymani Yazdi, Mahmood Moradi
Engineering (ENG) , 2011, DOI: 10.4236/eng.2011.37084
Abstract: In the presented study, the laser butt-welding of Ti 6Al 4V is investigated using 2.2 kw CO2 laser. Ti 6Al 4V alloy has widespread application in various fields of industries including the medical, nuclear and aerospace. In this study, Response Surface Methodology (RSM) is employed to establish the design of experiments and to optimize the bead geometry. The relationships between the input laser-welding parameters (i.e. laser power, welding speed and focal point position) and the process responses (i.e. welded zone width, heat affected zone width, welded zone area, heat affected zone area and penetration depth) are investigated. The multi-response optimizations are used to optimize the welding process. The optimum welding conditions are identified in order to increase the productivity and minimize the total operating cost. The validation results demonstrate that the developed models are accurate with low percentages of error (less than 12.5%).
冷模压制Ti-6Al-4V粉末的修正Drucker-Prager Cap本构模型 Modified Drucker–Prager Cap model of Ti–6Al–4V powders for cold die compaction  [PDF]
- , 2018,
Abstract: 通过单轴压缩实验、径向压缩(巴西圆盘)实验和冷模模压实验建立了基于密度相关修正Drucker–Prager Cap(DPC)的Ti–6Al–4V粉末压制本构模型,利用ABAQUS有限元仿真软件的二次开发用户子程序USDFLD对该本构模型进行了模拟验证。综合考虑压制过程中实验装置变形对实验数据的影响,通过空压校正实验控制实验误差,建立了更加准确的修正DPC模型。结果表明:修正DPC本构模型可很好地应用于Ti–6Al–4V粉末压制过程的仿真模拟;当上模冲压力较小时(<50 MPa),模壁摩擦系数随上模冲压力的增加逐渐减小,当上模冲压力较大时(>50 MPa),模壁摩擦系数随上模冲压力的增加而基本趋于稳定。

XU Zhensheng,GONG Bo,ZHANG Caibei,LAI Zuhan Northeast University of Technology,Shenyang,

金属学报 , 1991,
Abstract: 测定了各种氢含量对Ti-6Al-4V合金的流变应力(σ),应变速率敏感指数(m)和延伸率(δ)的影响,并对其微观结构进行了观察研究。结果表明,适量的氢对该合金在800—860℃范围内具有减少流变应力和降低超塑温度以及增加塑性的作用。
Caracterización de las transformaciones α β de la aleación Ti–6Al–4V y de las características mecánicas y microestructurales obtenidas  [cached]
Tarín, P.,Simón, A. G.,Piris, N. M.,Badía, J. M.
Boletín de la Sociedad Espa?ola de Cerámica y Vidrio , 2004,
Abstract: In the Ti-6Al-4V alloy, the α phase is gradually transformed into the β phase until β-transus temperature (≈ 1000 oC) is reached, and the transformation completed. It is important to identify transformation kinetics (mainly in other titanium alloy types, as near α) to accomplish solution heat treatments in which a phase α percentage (primary α) remains unchanged. In this paper, kinetics and other transformation characteristics are evaluated, as well as their influence on subsequent cooling transformations, by differential and dilatometric thermal analysis, electric conductivity measurements, hardness measurements and metallographic observation, after performing controlled thermal treatments. Starting from the mill annealed condition, samples were heated at temperatures between 650-1000 oC for 1 hour, then water quenched and subsequently heated at 530 oC for 6 hours, air cooled. Finally, the mechanical properties of samples heat treated as indicated above were obtained. En la aleación Ti-6Al-4V la fase α se va transformando en calentamiento en fase β hasta completarse al alcanzar la temperatura β-transus (≈1000 oC). La identificación de la cinética de esa transformación es importante (y más todavía en otros tipos de aleaciones de Ti, como las super-α) para realizar tratamientos de solución en los que se deja sin transformar un determinado porcentaje de fase α (llamada primaria). En el presente trabajo se estudia y se valora la cinética y otras características de esa transformación, así como su influencia en transformaciones posteriores en enfriamiento, mediante técnicas de análisis térmico (diferencial y dilatométrico) y con medidas de conductividad eléctrica, estudios metalográficos y medidas de dureza, llevados a cabo tras la realización de tratamientos térmicos controlados. Los tratamientos térmicos realizados, a partir del estado de entrega (mill annealed), fueron calentamientos de 1 hora a temperaturas entre 650 oC y 1050 oC, con enfriamiento en agua con agitación, y posterior calentamiento a 530 oC durante 6 horas y enfriamiento último al aire. Por otra parte, se han determinado las características mecánicas de muestras sometidas a esos tratamientos térmicos.
小麦-簇毛麦6VS/6AL易位染色体对小麦农艺性状的影响  [PDF]
植物遗传资源学报 , 2011,
Abstract: 南京农业大学细胞遗传研究所选育的小麦-簇毛麦6VS/6AL易位系在6VS上携有Pm21基因,用它作抗源已选育出一批高抗白粉病的新品系和新品种。为了研究6VS/6AL易位染色体对普通小麦农艺性状的影响,本研究选用由不同生态类型的推广品种与6VS/6AL易位系经过杂交回交选育的11个高代品系(种)及其轮回亲本和3份涉及6VS/6AL的高代分离品系以及5个F2群体,对产量、株高、穗长、穗粒数、穗粒重和千粒重等农艺性状进行比较分析。结果表明,6VS/6AL易位染色体对后代的小穗数、穗粒数、穗粒重和产量等农艺性状没有表现出明显的影响,对穗长和千粒重表现出一定的正向效应。多数6VS/6AL衍生品系的株高与亲本相比有所增加,但在同一组合的不同品系之间表现出一定的差异,在育种过程中通过选择能够改变增高趋势。6VS/6AL易位系对白粉病免疫,并且遗传稳定,对小麦的抗病育种是很有潜力的抗源亲本。
Estudo epidemiológico das fraturas femorais diafisárias pediátricas Epidemiological study of children diaphyseal femoral fractures  [cached]
Cassiano Ricardo Hoffmann,Eduardo Franceschini Traldi,Alexandre Posser
Revista Brasileira de Ortopedia , 2012, DOI: 10.1590/s0102-36162012000200007
Abstract: OBJETIVO: Avaliar as características pessoais, das fraturas e do tratamento e suas complica es em pacientes com fraturas femorais diafisárias pediátricas atendidos no Servi o de Ortopedia Pediátrica do Hospital Infantil Joana de Gusm o. MéTODOS: Trata-se de estudo retrospectivo e transversal com popula o composta por pacientes com fraturas diafisárias de fêmur, com idade entre o nascimento e 14 anos e 11 meses, divididos em quatro grupos etários. As informa es foram obtidas nos prontuários e transferidas para o questionário de pesquisa que apresentava variáveis pessoais, das fraturas e do tratamento e suas complica es. RESULTADOS: A popula o do estudo foi composta por 96 pacientes. A média de idade encontrada foi de 6,8 anos. Houve predomínio no sexo masculino, fratura fechada, lado direito, 1/3 médio e tra o simples. Quanto à etiologia das fraturas, houve predomínio na amostra global de acidentes de transito. A maioria dos pacientes (74-77,1%) apresentou fratura de fêmur como les o isolada. Houve predomínio do tratamento conservador na faixa etária menor que seis anos e do tratamento cirúrgico na faixa etária de seis anos a 14 anos e 11 meses. As complica es observadas até a uni o óssea foram: discrepancia, infec o e limita o de movimento. O tempo médio de consolida o foi de 9,6 ± 2,4 semanas, variando com a idade. CONCLUS O: As características das fraturas estudadas foram semelhantes às citadas na literatura e o tratamento empregado apresentou bom resultado. O Hospital Infantil Joana de Gusm o (HIJG) tem utilizado o tratamento proposto pela literatura nas fraturas femorais diafisárias pediátricas. OBJECTIVE: To evaluate the personal, fracture, treatment and complication characteristics among patients with pediatric femoral shaft fractures attended at the pediatric orthopedic service of the Joana de Gusm o Children's Hospital. METHODS: This was a retrospective cross-sectional study on a population consisting of patients with femoral shaft fractures, aged between birth and 14 years and 11 months, who were divided into four age groups. Information was obtained from medical records and was transferred to a survey questionnaire to present personal, fracture, treatment and complication variables. RESULTS: The study population consisted of 96 patients. Their mean age was 6.8 years. The cases were predominantly among males, comprising closed fractures on the right side, in the middle third with a single line. Regarding fracture etiology, traffic accidents predominated overall in the sample. Most of the patients (74 to 77.1%) presented femoral fractur
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