The Fe-A1-Ti system

An extensive experimental investigation of the Fe-Al-Ti system by metallography, microprobe analysis, and XRD on quenched specimens and on diffusion couples is presented. Two isothermal sections at 800 and 1000 °C were established; they differ substantially from the existing (800 °C) or partly determined (1000 °C) diagrams. From these results, existence of the τ₁ phase (Fe₂AlTi) can be ruled out. Existence of the ternary compounds, τ₂ (Al₂FeTi) and τ₃ (Al₂₂Fe₃Ti₈), is confirmed. The composition limits of both phases were determined; they differ considerably from those given in earlier reports. The τ₂ phase apparently exists in a cubic and a tetragonal polymorph, depending on composition. The cubic form exists at high titanium contents. At 1000 °C, the two polymorphs are separated by a miscibility gap. At compositions where the “X phase” (Al₆₉Fe₂₅Ti₆) was previously reported, single-phase samples were obtained at both temperatures. From the present results, there is no evidence to assume that this is a new ternary phase rather than the ternary homogeneity range of the Al₃Fe phase. In addition, extensions of the binary intermetallic phases into the ternary system were determined.     

Fe-Al合金有序化过程中的内耗峰

利用内耗方法对B2 Fe-Al合金的有序化过程进行了研究,并分析了有序化过程与原子换位运动之间的关系.对于油冷Fe47Al53合金,在570℃左右观察到一个内耗峰;但是对于炉冷样品,该峰并不出现.这个内耗峰具有典型的相变峰特征,XRD和DSC显示,该峰的出现与样品的有序化过程有关,它产生于反位链原子通过最近邻的空位向自身亚晶格位置的跳动. 油冷Fe57Al43合金中类似的峰出现在540℃附近.     

搅拌摩擦加工制备Al-Ti金属间化合物

以纯铝为基材,Ti粉为合金化添加粉末.利用搅拌摩擦加工方法制备Al-Ti金属间化合物.利用光学显微镜和X射线衍射分析了材料的微观组织和相组成,并测试了合金化区域的显微硬度.结果表明:通过搅拌摩擦加工技术可以制备出Al3Ti金属间化合物,但材料中各部分化合物成分不均匀;合金化后的化合物晶粒尺寸细小,几乎达到微米级;生成化合物处的显微硬度达到65HV.     

搅拌反应合成Al-Ti金属间化合物强化铝基复合材料的工艺

分别采用冰晶石与二氧化钛、冰晶石与钛粉、氟钛酸钾为加入物,通过搅拌原位合成TiAl3/7075铝基复合材料,从热力学角度分析反应的可能性,并借助光学显微镜(OM)、X射线衍射分析仪(XRD)、扫描电镜(SEM)及能谱分析仪(EDX)分析复合材料的微观组织及物相。结果表明,3种加入物都可以制备铝基复合材料,而冰晶石与钛粉的加入物为制备TiAl3/7075铝基复合材料的最佳反应物。     

MoS2-Ti复合膜的结构及其抗氧化性能

利用非平衡磁控溅射仪在碳/碳复合材料表面制备了MoS2-Ti复合膜.采用XRD,Raman光谱、X射线光电子能谱仪对其结构进行了表征,并利用X射线光电子能谱仪对复合膜的抗氧化性能进行了研究.研究结果表明:所制备的MoS2-Ti复合膜为非晶态结构;MoS2-Ti复合膜具有良好的抗氧化性能,将其在蒸馏水中浸泡200 h后,Mo4+没有被氧化.     

The ordering behavior of supersaturated metastable phases in β-Ti alloys

A phase resulting from quenching solution treated beta-Ti alloys has long been recognized as a metastable structure containing unusual phenomena, and is not well understood. Tweed structure consisting of the metastable phase was observed by transmission electron microscopy, and spot satellites inflicted by streaks were also observed in the lattice diffraction. The results of microstructural studies and diffraction pattern surveys have identified the metastable structure as the elastic strain zone caused by the supersaturation of solute atoms, which may be induced by the electron charge distribution and atomic bonding between solvent matrix and solute atoms, causing the tweed structure. This paper presents the main finding of a microstructural abnormality, and compares the results with ordering behavior such as premartensitic transformation, and reviews a new regularity generated in the metastable phase of the supersaturated state.     

MoS2-Ti复合膜的结构及其抗氧化性能

利用非平衡磁控溅射仪在碳/碳复合材料表面制备了MoS2-Ti复合膜.采用XRD,Raman光谱、X射线光电子能谱仪对其结构进行了表征,并利用X射线光电子能谱仪对复合膜的抗氧化性能进行了研究.研究结果表明所制备的MoS2-Ti复合膜为非晶态结构;MoS2-Ti复合膜具有良好的抗氧化性能,将其在蒸馏水中浸泡200 h后,Mo4+没有被氧化.     

SHS制备Al-Ti-C晶粒细化剂研究

利用自蔓延高温合成了Al-Ti-C晶粒细化剂,并通过金相显微镜分析了其组织.结果表明:SHS反应的主要能量来自于Ti(s) 3Al(1)=Al3Ti(s)的合成反应,镁以块状和粉状按比例加入且含量控制在1%时组织最佳.     

生物医用型β型钛合金的设计与开发

介稳定β型钛合金具有低密度、高比强度、低模量、耐蚀、易加工且生物相容性优良等特点，已成为外科植入件优选的替代材料。本文重点介绍了用于人体硬组织修复与替代材料的介稳定口型生物医用钛合金的设计、熔炼、加工、热处理、显微组织以及表面改性等方面应注意的问题和最新研究进展，并指出了未来的研究发展方向。     

钛合金中的有序化Ⅱ:短程序强化

用Flinn模型计算了二元钛合金α-Ti-SM(SM=Al,Si,Ga,Ge)中短程序强化对临界剪切应力的贡献.计算结果表明,短程序强化显著提高了Ti-SM合金的强度,短程序强化率从Al,Ga,Ge到Si依次增加.     

Spark anodizing of β-Ti alloy for wear-resistant coating

Spark anodizing of a bcc solid solution Ti-15% V-3% Al-3% Cr-3% Sn alloy has been performed in an alkaline electrolyte containing aluminate and phosphate using dc-biased ac anodizing to form a wear-resistant coating on the alloy. The coating consists mainly of Al₂TiO₅, with rutile and γ-Al₂O₃ being present as minor oxide phases. Depth profiles of the coating, examined by glow discharge optical emission spectroscopy, have revealed that aluminium species, highly enriched in the coating, distribute uniformly in the coating, while phosphorus species, incorporated from the electrolyte, are located mainly in the inner part of the coating near the coating/alloy interface. The location of the phosphorus species should be associated with the porous nature of the coating, allowing access of the electrolyte directly to the inner parts of the coating. The porosity of the coating is reduced by anodizing to high voltages. The marked improvement of the wear resistance by the coating has been demonstrated from a pin-on-disc wear test.     

MgH2-Ti体系解氢能力的第一原理计算

采用基于密度泛函理论的第一原理赝势平面波方法,计算了不同含量的Ti固溶于镁氢化合物(MgH2)中形成(MgTi)H2,析出TiH2相形成TiH2/MgH2相界的能量与电子结构.负合金形成热的计算结果表明:对MgH2进行Ti合金化,体系相结构的稳定性变差,Ti在MgH2中固溶以及TiH2/MgH2相界的存在均有利于MgH2解氢能力的增强.电子态密度(DOS)与电子密度的进一步分析发现:合金化体系解氢能力增强的主要原因在于Mg-H之间的成键作用较弱,以及Ti诱导费米能级EF处电子密度N(EF)的增加和EF附近HOMO-LUMO能隙△EH-L的变窄甚至消失.     

Microstructure and properties of 2618-Ti heat resistant aluminum alloy

1　INTRODUCTIONAluminumalloy 2 6 18isaheat treatableAl Cu Mg Fe Niforgingalloywhichiswidelyusedinair craftenginecomponentsandautomobileindustries[1] .ItisaheatresistantstructurematerialfabricatedbyI/Mtechnique .TheadditionofsmallamountofFeandNiproducesmicrostructuralstabilityunderther malexposure .Themain precipitatesarecoherentGuinier Preston Bagaryatskii (GPB )zoneswhichformrapidlyonagingattemperaturesuptoatleast2 0 0℃andsemi coherentS′(Al2 CuMg) phasewhichcanapparentlystrength…     

Au-Ti足金的强化机理研究

采用拉伸试验、硬度测试和光学显微分析等手段研究了Au-Ti足金的强化机理。结果表明，Au-Ti足金的强化方式主要是细晶强化、加工硬化和时效强化，且其力学性能优于标准的Au917饰品用金合金Au917Ag55Cu28，Au917Ag32Cu51。并且，Au-Ti足金的冷加工性能优于千足金，这是由于其固溶态硬度、强度高，延性好。     

Ni-Ti基形状记忆合金的研究与应用

Ni-Ti合金是一种性能优良的形状记忆材料。本文主要介绍了它的基本特性、相图和马氏体晶体结构 ,并简单介绍了Ni-Ti-Cu和Ni-Ti-Nb两种具有代表性的Ni-Ti基合金 ,以及Ni-Ti基合金在工程和医学中的应用。     

Microstructural and tribological behavior of TiAlN/MoS2-Ti coatings

1. Introduction The search for a better wear resistant coating has resulted in the development of a class of hard, solid-lubricated coatings. The driving force behind the coating industry was the need to develop a proc-ess that will extend the life of steel machine parts, cutting tools, molding dies, and sliding parts. For example, in the stamping industry, severe abrasive wear and galling (cold metal welding) are expected. There is the need for an efficient application of lu-bricants both for…     

一种新型亚稳定β钛合金的组织与性能研究

研究了一种新型的亚稳定β钛合金在α β两相区固溶时效处理(850℃×1h AC 600℃x6h AC)、β区固溶时效(880℃×lh AC 600℃×6h AC)、α β和β双重处理(850℃×0.5 h→880℃×0.5h AC 600℃×6h AC)3种热处理状态下的显微组织与力学性能.结果表明,850℃固溶处理没有改变原始加工态组织形貌;880℃固溶的显微组织为再结晶晶粒,低温时效后析出少量的α相;β (α β)双重处理后的显微组织为再结晶的β晶粒内析出较多的α相.无论在α β区还是在β区固溶时效处理,该合金都具有很好的强度短线塑性匹配关系,且达到了很高的强度级别;再结晶对于提高合金的断裂韧性有利,但从保持合金塑性的角度,固溶温度不宜选择在β温度区.因此将固溶温度定在α β两相区的接近β相变点的850℃是相对合理的.     

钛合金中合金原子与空位的相互作用

用第一原理方法计算了二元α-Ti合金中合金原子与空位间的相互作用,合金元素包括周期表中第三到第五周期中的大部分元素.结果表明,第四周期中除Sc外的过渡族合金原子均与空位互相排斥;简单金属及所有第五周期的过渡族合金原子均与空位互相吸引.用电子结构理论解释了钛合金中合金原子-空位相互作用能随原子序数变化的趋势.讨论了合金原子-空位相互作用对合金蠕变性能的可能影响.     

Neutron diffraction study of oxygen dissolution in α2-Ti3Al

Rietveld refinements of neutron powder diffraction data on α₂-Ti₃Al have been performed to determine the crystal structure as a function of interstitial oxygen (O) concentration for three alloys with a Ti/Al ratio of ≈2.34 and O concentrations of 0.25, 3.99, and 7.71%. The structures of the alloys are hexagonal in space group P6₃/mmc where Ti and Al atoms populate unique sites with excess Al at the Ti site and O atoms occupy octahedral interstitial sites surrounded by six Ti sites. The length of the c-axis was found to increase linearly as the O occupancy of the interstitial sites increased; this lattice lengthening effect was much less pronounced along the a-axis. Correspondingly, the increases in the lengths of Ti–Al and Ti–Ti bonds with a major component of their direction parallel to the c-axis were roughly an order of magnitude greater than the increases in the lengths of Ti–Al and Ti–Ti bonds more closely aligned with the a-axis. Densities calculated from the lattice parameters and occupancy factors fall in the range (4.118±0.004) to (4.194±0.004) g/cm³, and exhibit a nearly linear increase with oxygen concentration. Measured densities of (4.113±0.001), (4.146±0.009), and (4.191±0.002) g/cm³ for these alloys agree with the results of the refinements.