涂层对TI纤维与Ti／TiAl复合材料性能影响的研究

研究了涂层对Ｔｉ纤维及Ｔｉ纤维强化γ－ＴｉＡｌ金属间化合物基复合材料性能的影响。研究结果表明，运用物理气相沉积法（ＰＶＤ）在Ｔｉ纤维表面涂覆Ｙ２Ｏ３制得Ｔｉ／ＴｉＡｌ复合材料，不仅改善了γ－ＴｉＡｌ及其复合材料的力学性能，而且使纤维与基体间的界面反应层厚度减小，涂覆Ｙ２Ｏ３较Ａｌ２Ｏ３有较高的稳定性，这对深入研究涂层对复合材料合成及性能的影响有着重要的意义。     

TiO2／Al烧结反应生成的Al2O3／TixAly复合材料研究

采用挤压铸造法，先制备ＴｉＯ２／Ａｌ坯块，经随后高温烧结反应，可生成Ａｌ２Ｏ３／ＴｉｘＡｌｙ复合材料。ＤＴＡ分析表明ＴｉＯ２粉末与纯Ａｌ之间的反应具有放热特征。Ｘ射线衍射分析与透射电镜观察发现反应产物主要为α－Ａｌ２Ｏ３与ＴｉｘＡｌｙ。反应过程中ＴｉＯ２粉末首先被熔融态Ａｌ还原成α－Ａｌ２Ｏ３与Ｔｉ，而后Ｔｉ与Ａｌ通过扩散反应形成多种ＴｉｘＡｌｙ金属间化合物。     

Ti—AlN是面组分分布的二次离子质谱研究

采用电子束蒸发方法在２００℃的抛光ＡｌＮ陶瓷衬底上淀积厚度为２００ｎｍ的Ｔｉ膜，并在高真空中退火。利用二次离子质谱对样品进行了深度剖析，给出了Ｔｉ／ＡｌＮ界面组分分布随退火温度和时间的变化关系。在界面区发现了铝化物及其他反应产物。结合卢瑟福背散射谱，Ｘ射线衍射分析和Ｔｉ－Ａｌ－Ｎ三元相图推断，铝化物是Ｔｉ－Ａｌ二元和Ｔｉ－Ａｌ－Ｎ三元化合物。     

颗粒增强Ti－Al化合物基复合材料

本文在介绍Ｔｉ－Ａｌ金属间化合物基体及其颗粒增强剂的基础上，重点讨论了利用ＸＤ合成法、自蔓延高温合成法及真空热压法制造ＴｉＢ２、ＳｉＣ、Ａｌ２Ｏ３、ＴｉＮｂ等颗粒增强Ｔｉ－Ａｌ金属间化合物基复合材料的力学性能，同时还对颗粒增强Ｔｉ－Ａｌ金属间化合物基复合材料的其它制造方法，如反应热压烧结法、冲击波固结法、高能高速法的工艺、特点也进行了简要叙述。     

Al-Ti-TiO2体系燃烧合成及其反应过程研究

利用Ａｌ－Ｔｉ－ＴｉＯ_２体系放热反应,采用自蔓延高温合成工艺。原位合成了ＴｉＡｌ基体和Ａｌ_２Ｏ_３颗粒,成功制备出ＴｉＡｌ／Ａｌ_２Ｏ_３复合材料．结合差热分析,通过对不同温度下反应产物相组成分析;对Ａｌ－Ｔｉ－ＴｉＯ_２体系燃烧反应过程进行了初步研究．结果表明,铝热还原反应是一个分步过程,先期发生的Ａｌ－Ｔｉ、Ｔｉ－ＴｉＯ_２反应降低了Ａｌ－ＴｉＯ_２还原反应的起始温度．     

钛合金的超塑性成型与扩散焊接

在超塑性成型／扩散焊接（ＳＰＦ／ＤＢ）联合工艺生产的零部件中，绝大多数是由Ｔｉ－６Ａｌ－４Ｖ制造的。这一材料的缺点是使用温度低且ＳＰＢ／ＤＢ温度高。具有较镐工作温度的近α钛合金及含钛－铝金属间化合物（ＴｉＡｌ或Ｔｉ３Ａｌ）的钛合金材料正肥到越来越广泛的重视。β相转变温度对钛合金的使用温度及ＳＰＦ／ＤＢ温度有很大影响。本文以Ｔｉ－６Ａｌ－４Ｖ为基础，比较了其它几种新型钛合金的ＳＰＦ／ＤＢ行为。其中包     

基体合金化元素Cu对C／Al复合材料界面微结构的影响

本文研究用真空压力浸渍法制造的Ｃ／纯Ａｌ和Ｃ／Ａｌ－Ｃｕ两种复合材料界面微观结构的差异。探求合金化元素Ｃｕ的作用本质。结果表明，Ｃ／Ａｌ－Ｃｕ复合材料界面存在有ＣｕＡｌ２，Ａｌ４Ｃ３，ＡｌＣｕ三种脆性化合物，还发现ＣｕＡｌ２对Ａｌ４Ｃ３的形核影响不明显，但对它的长大有抑制作用。正是由于这种影响，使Ｃ／Ａｌ－Ｃｕ复合材料的耐用温度提高。     

金属基复合材料的熔体直接反应合成工艺

介绍了一种新型金属基复合材料制备工艺－熔体直接反应合成工艺，重点介绍了Ａｌ３Ｔｉ／Ａｌ、ＴｉＢ／Ａｌ、ＴｉＣ／Ａｌ颗粒增强复合材料制备工艺及其性能。     

TiO2—Al—B系反应烧结制备的复相陶瓷和原位Al基复合材料

采用反应烧结方法，利用ＴｉＯ２，Ａｌ和Ｂ粉末间的放热反应的较低的温度下制备Ａｌ２Ｏ３－ＴｉＢ２复相陶瓷和原位生长Ａｌ２Ｏ３和ＴｉＢ２弥散粒子增强Ａｌ复合，Ａｌ２Ｏ３－ＴｉＢ２复相陶瓷是密度ρ－０．８的多孔体，由尺寸小于２μｍ，在基体中呈现均匀分布，没有发现Ａｌ３Ｔｉ生成，这种原位Ａｌ基复合材料具有优于ＳｉＣｗ／Ａｌ复合材料的强度。     

TiAl及TiC／TiAl合金的XD合成研究

本文研究了用ＸＤ工艺合成ＴｉＡｌ合金及ＴｉＣ／ＴｉＡｌ复合材料，研究结果表明，可在Ａｌ的熔点附近用ＸＤ工艺制备ＴｉＡｌ合金及其ＴｉＣ颗粒增强复合材料。ＴｉＡｌ合金由ＴｉＡｌ＋Ｔｉ３Ａｌ相组成，而ＴｉＣ／ＴｉＡｌ复合材料由ＴｉＣ＋ＴｉＡｌ＋Ｔｉ３Ａｌ相组成。     

Finite element analysis of substation composite insulators

Composite insulators are rapidly replacing their porcelain counterparts in electrical substation applications. These insulators consist of a glass-reinforced polymer (GRP) rod, with two metal end fittings radially crimped onto the ends of the rod during assembly. In this paper, axisymmetric finite element models are developed to evaluate the mechanical performance of composite insulators under externally applied axial compression. The analyses are performed by assuming both a perfectly bonded interface between the composite rod and the end fittings, and an imperfect interface which permits large relative sliding with Coulomb friction. Results indicate that the perfect interface model is unrealistic since it predicts singular stresses at the interface comer and an overall linear structural response. On the other hand, the imperfect interface model is found to simulate accurately the structural non-linearity caused by relative sliding of the GRP rod within the end fittings. The imperfect interface model has therefore been used to evaluate the effects of interface friction, and the extent of crimping, on the maximum load-bearing capacity of substation composite insulators.     

Ceramic matrix composite-metal brazed joints

A silicon nitride fibre-reinforced cordierite glass ceramic matrix composite has been brazed to titanium and stainless steel in argon with four different interlayer materials, copper, nickel, tungsten and a metal matrix composite (mmc). Joints were tested in shear and all but one failed in the ceramic composite. The highest strength joint, using a metal matrix interlayer to join cmc to stainless steel failed in the mmc at 106 MPa. Silver-copper eutectic braze and aluminium braze can be used to join metals to titanium-coated cmc, producing joints with low levels of interfacial defects. Some joints, however, show debonding at the edges where residual shear stresses are highest.     

Characterization of the whisker–matrix interfacial reactions in K2O·6TiO2 whisker-reinforced aluminium matrix composites

The interfacial reaction at the whisker–matrix interface in a K2O·6TiO2/6061Al composite was investigated by high-resolution transmission electron microscopy. Magnesium segregation and titanium enrichment at the whisker–aluminium interface was revealed by energy-dispersive X-ray analysis. It was shown that TiO and MgTi2O4 layers and MgAl2O4 particles were formed at the whisker–aluminium interfaces in the composite during the manufacturing of the composite. The thickening of the reaction layer after T6 treatment may result in the decrease of the bending strength of the composite. Specific orientation relationships between MgTi2O4 and TiO, and also between TiO and K2O·6TiO2 whiskers were also found.     

The Al2O3-t itanium adhesion in the view of the diffusion bonding process

One of the key aspects of the diffusion bonding technology is the adhesion at the interface, to whom most of the mechanical properties can be ascribed. Titanium has been largely used in diffusion bonding involving aluminium oxide, as it reacts with the ceramic promoting adhesion. The present work attends to the interface formation between Al₂O₃ and titanium, during diffusion bonding experiments performed under vacuum. It is verified, by SEM microstructure characterisation, EDS microanalysis, X-ray diffraction and microhardness measurements, that the adhesion occurred by the ceramic dissolution, in presence of titanium, in elementary aluminium and oxygen atoms, followed by the oxygen diffusion into the titanium. The aluminium accumulation at the interface is favourable to the Ti₃Al formation observed.     

Interfacial reactions between titanium film and single crystal α-Al2O3

Titanium is commonly used to join metals and ceramics by active metal brazing methods. In this work, titanium was sputter deposited on to single-crystal -Al₂O₃ substrates and the interfacial reactions between the titanium film and the Al₂O₃ substrate were studied. Al₂O₃ was reduced by titanium when samples were annealed at 973 and 1173 K for 300 s in an argon gas flow. Metallic aluminium was produced at the interface, and this diffused from the interface into the titanium film. At 1173 K, the intermetallic compound Ti₃Al and the intermediate titanium oxides, such as Ti₂O and TiO, were formed. The Al⁰ diffusion is important in stimulating interfacial reactions.     

Study of the Ti/Al2O3 interface

The Ti/Al₂O₃ (1 ¯1 0 2) interface formation has been investigated by X-ray photoelectron spectroscopy and Auger electron spectroscopy (AES). The results showed that when an active metal titanium was evaporated on to a room-temperature Al₂O₃ (1 ¯ 1 0 2) surface in ultrahigh vaccum, a Ti/Al₂O₃ interface region of about 200 nm was formed, and in the first several monolayers of titanium, the titanium was oxidized due to the active oxygen anions on the surface. Therefore, the pure Ti/Al₂O₃ interface was replaced gradually by a titanium oxides/Al₂O₃ interface, which has a stronger interaction than the former. The change of shape of the photoemission lines and the shift of binding energy of aluminium, oxygen and titanium with increasing coverage of titanium showed that the formation of the Ti-O bond at the interface is due to titanium transferring its electrons to Al³⁺ via O^2– anions in the Al-O bond, whereby the Al³⁺ was reduced to metallic aluminium, Al⁰. The AES intensity profile also proved the existence of the reduced species Al⁰. This suggests that the reaction layer consists of a multiphasic mixture: the Ti-O type phase, the (Ti, Al)₂O₃ phase and metallic aluminium phase.     

Ti/Al_2O_3界面的光电子能谱研究

用X射线光电子谱（XPS）和俄歇电子能谱（AES）研究了Ti／Al_2O_3界面形成的过程。研究表明，活性金属Ti在室温下能与衬底Al2O3（1102）形成约20nm强结合的界面区。从Al，O，Ti的光电子谱形状变化以及它们随着Ti覆盖度的增加而出现结合能位移表明，在界面处形成的反应层中，最初几个单层的Ti很容易被Al2O3表面的活性氧所氧化，从而使Ti／Al2O3界面逐步由具有更强相互作用的TiOx／Al2O3界面所代替，并形成由多相混合体［Ti-O相，（Ti，Al）2O3相以及金属Al相］所组成的界面区。就是说，Ti通过Al—O键的O2-离子转移其电子给Al3 并使它还原成金属Al，从而形成Ti－O键所致。本文用AES强度剖面分析观察到了这种被还原的Al。     

The wetting of alumina by copper alloyed with titanium and other elements

The wettability of alumina by ternary alloys of copper, titanium and aluminium, gallium gold, indium, nickel or silver has been investigated using sessile drop tests conducted in vacuum at 1050–1250° C. Substantial additions of titanium are known to induce copper to wet alumina due to the formation of a titanium rich reaction product at the alloy/ ceramic interface, but the present work has shown that the concentration of titanium can be reduced by the addition of ternary alloying elements. Additions of indium are very beneficial, of aluminium, gold or silver are moderately beneficial, and of gallium or nickel are of negligible benefit or detrimental. These observations, and previous work with copper-tin-titanium alloys [1] can be interpreted in terms of effects on the activity of titanium which it is argued will be enhanced if the ternary alloying element has a low surface energy and is readily saturated by titanium. The correlation of the experimental wetting observations with the surface energy and titanium solubility data for the ternary alloying elements provides a basis for the rational development of reactive metal brazes for joining unmetallized ceramics.     

Experimental investigation on mechanical properties and wear characterization of Al-Si12CulMg1 aluminium alloy reinforced with titanium diboride and boron carbide particulate hybrid composites using stir casting process

LM13 aluminium alloy (Al−Si12CulMg1) with titanium diboride (TiB₂) and boron carbide (B₄C) particulate hybrid composites have been prepared using stir casting process. Wt% of titanium diboride is varied from 0–10 and constant 5 wt% boron carbide particles have been used to reinforce LM13 aluminium alloy. Microstructure of the composites has been investigated and mechanical properties viz., hardness, the tensile strength of composites have been analyzed. Wear behavior of samples has been tested using a pin on disc apparatus under varying load (20 N–50 N) for a sliding distance of 2000 m. Fracture and wear on the surface of samples have been investigated. Microstructures of composites show uniform dispersion of particles in LM13 aluminium alloy. Hardness and tensile strength of composites increased with increasing wt % of reinforcements. Dry sliding wear test results reveal that weight loss of composites increased with increasing load and sliding distance. Fracture on the surface of composites reveals that the initiation of crack is at the interface of the matrix and reinforcement whereas dimples are observed for LM13 aluminium alloy. Worn surface of composites shows fine grooves and delamination is observed for the matrix.     

Development of Some Fundamental Research of SiC_W/Al Composites in HIT PartⅠ Microstructure and SiC/Al Interface of SiC_W/Al Composites

The microstructure of SiC whisker reinforced aluminium alloy (SiC_w/Al) composite is reviewed,andthe SiC-Al interface in SiC_w/Al composite is especially discussed,The main contents aremorphology of the aluminium matrix in SiC_w/Al composite;microstructures and defects of SiCwhiskers in SiC_w/Al composite and bonding mechanisms of the SiC-Al interface in SiC_w/Al com-posite.