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。     

颗粒类型对颗粒增强铝基复合材料性能的影响

本文对粉末冶金法制备的ＳｉＣ和ＴｉＣ颗粒增强铝基复合材料进行了研究。试验表明，在颗粒含量相同、尺寸相当的条件下，ＴｉＣ增强Ａｌ基复合材料的强度和模量均低于ＳｉＣ增强Ａｌ基复合材料，但其屈强比却明显高于ＳｉＣ增强Ａｌ基复合材料。高温长时间等温处理对ＴｉＣ颗粒增强纯Ａｌ复合材料的强度没有明显的影响。     

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。     

Ti—Al—C系热爆反应制备TiC／Al复合材料的研究

以Ｔｉ，Ａｌ，Ｃ粉末为原料，用热爆反应制备了原位ＴｉＣ颗粒增强的ＴｉＣ／Ａｌ的Ａｌ基复合材料。研究了Ｔｉ－Ａｌ－Ｃ系热爆合成过程，探讨了热爆合成ＴｉＣ粒子的形成机制，研究表明，生成了ＴｉＣ粒子呈球形，尺寸均匀，且随体系中含Ａｌ量的增加，热爆反应合成ＴｉＣ的温度降低，ＴｉＣ颗粒尺寸减小。     

Ti-Al-C系热爆反应制备TiC/Al复合材料的研究

以Ｔｉ，Ａｌ，Ｃ粉末为原料，用热爆反应法制备了原位ＴｉＣ颗粒增强的ＴｉＣ／Ａｌ的Ａｌ基复合材料。研究了Ｔｉ－Ａｌ－Ｃ系热爆合成过程，探讨了热爆合成ＴｉＣ粒子的形成机制。研究表明：生成的ＴｉＣ粒子呈球形，尺寸均匀，且随体系中含Ａｌ量的增加，热爆反应合成ＴｉＣ的温度降低，ＴｉＣ颗粒尺寸减小。     

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。     

原位形成Al3Ti颗粒对SiCp／2024Al复合材料性能及微观结构的影响

本文采用粉末冶金法制制备了含Ｔｉ的ＳｉＣｐ／２０２４Ａｌ复合材料。研究表明，在复合材料制备工艺条件下，部分Ｔｉ与Ａｌ反应形成了Ａｌ３Ｔｉ，粗大的Ａｌ３Ｔｉ／Ｔｉ复合颗粒的存在降低了复合材料的室温拉伸强度和塑性，但可以提高屈服强度和弹性模量。     

TiO_2－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粉末间的放热反应在较低的温度下制备Ａｌ２Ｏ３－ＴｉＢ２复相陶瓷和原位生长Ａｌ２Ｏ３和ＴｉＢ２弥散粒子增强Ａｌ复合材料Ａｌ２Ｏ３－ＴｉＢ２复相陶瓷是密度ρ～０．８的多孔体，由尺寸约１０μｍ的生长单元构成晶粒，在陶瓷中还含有少量的Ａｌ３Ｔｉ．Ａｌ基复合材料中原位形成的Ａｌ２Ｏ３和ＴｉＢ２粒子尺寸小于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．     

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。     

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。     

热处理对EB-PVD制备的TiAl/Nb复合材料微观组织的影响

对利用EB-PVD技术制备的TiAl/Nb微层板进行了热处理,分析了沉积态材料与热处理态材料的组织结构和物相的变化。热处理TiAl/Nb中态富Ti的TiAl层中成分沿沉积方向呈有规律的梯度变化但未形成周期,界面处的反应扩散区由B2相组成;TiAl层、扩散区和Nb层的显微组织形貌依次为含月牙形亚晶的柱状晶、细小等轴晶和粗大等轴晶;经1000℃/16h的真空退火处理后,Nb层和扩散区会因完全扩散而消失。     

TiAl基合金板材制备技术的发展现状

综述了TiAl基合金板材制备技术的发展现状。介绍了的制备TiAl基合金板材三种技术的工艺过程及制得的TiAl基合金板材的显微组织和力学性能。     

Stoichiometry Effects in TiAl and TiAlCr Alloys

Analytical electron microscopy methods have been used to establish correlatjons between lattice parameters and phase compositions in binary TiAl and ternary TiAlCr alloys based on Ti-48 at.-%Al.On traversing the stoichiometric composition in the binary TiAl system the lattice parameters show linear relationships with Al concentration suggesting antisite defects influence the structural parameters. The relationship between lattice parameters and phase composition in the ternary TiAl (Cr) phase is influenced by the site occupation behaviour of Cr in the TiAl lattice. Comparisons are made between" bulk" and" local" measurements for obtaining such information in complex two-phase alloys. Possible implications for the mechanical properties are briefly discussed.     

Defects and Electron Densities in TiAl-based Alloys Containing Mn and Cu Studied by Positron Annihilation

The defects and electron densities in Ti50Al50, Ti50Al48Mn2 and Ti50Al48Cu2 alloys have been studied by positron lifetime measurements. The results show that the free electron density in the bulk of binary TiAl alloy is lower than that of pure Ti or Al metal. The open volume of defects on the grain boundaries of binary TiAl alloy is larger than that of a monovacancy of Al metal. The additions of Mn and Cu into Ti-rich TiAI alloy will increase the free electron densities in the bulk and the grain boundary simultaneously, since one Mn atom or Cu atom which occupies the Al atom site provides more free electrons participating metallic bonds than those provided by an Al atom. It is also found the free electron density in the grain boundary of Ti50Al48Cu2 is higher than that of Ti50Al48Mn2 alloy, while the free electron density in the bulk of Ti50Al48Cu2 is lower than that of Ti50Al48Mn2 alloy. The behaviors of Mn and Cu atoms in TiAI alloy have been discussed.     

Preparation of TiAl/Mo and TiAl/NiAl composites by powder processing

Processes for preparing TiAl/Mo and TiAl/NiAl composites are described and results of the investigation are reported. It was found that the hardness of the TiAl/NiAl composites was largely influenced by the amount of hard ternary phases formed through reactions between TiAl and NiAl. The possibility of ductilizing and toughening TiAl by introducing molybdenum as a ductile reinforcement has also been shown. For both composites, optimal process parameters still remain to be determined by further experiments to suppress the formation of hard ternary phases, which are believed to be detrimental to ductility and fracture toughness. This revised version was published online in November 2006 with corrections to the Cover Date.     

TiAl合金精密成形技术发展现状及展望

TiAl合金是一种优异的轻质耐高温结构材料,在航空、航天、汽车、兵器等热端部件制造领域具有广阔的应用和发展前景,但其较低的室温塑性、韧性和较差的冷/热加工性能,限制了其工程化的进程.为挖掘TiAl合金的应用潜力,国内外研究机构和企业从材料设计、组织性能调控到成形工艺等方面开展了卓有成效的研究.总结了近年来国内外在TiA...     

Bone tissue reaction to Ti–48Al–2Cr–2Nb (at.%) in a rodent model: a preliminary SEM study

A variety of metals have been used to replace the skeletal framework of human beings. Gamma titanium aluminide (γTiAl) has been recently developed as a prospective material for turbine applications. In this preliminary study, the potential of γTiAl as a biomaterial was evaluated using an in vivo rat model. Sprague–Dawley rats were implanted with γTiAl cylinders in the femur and observed for an experimental period lasting up to 180 days. The rats were sacrificed after periods of 45, 90 and 180 days. The femurs with the γTiAl implants were extracted and examined using scanning electron microscopy (SEM). Normal bone growth processes were observed as early as 45 days after γTiAl cylinder implantation. No signs of rejection of the implant metal were observed. In fact, a layered bone growth was observed on the implant metal surface. The bone–metal interface showed signs of tissue growth from original bone to the metal surface. γTiAl appears to elicit a normal bone tissue reaction and hence, has potential as a metallic implant material.     

Nb-TiAl 金属间化合物研究现状

论述了Ｎｂ－ＴｉＡｌ系金属间化合物在高温强度及抗氧化性方面已取得的进展。高熔点组元Ｎｂ提高了合金的熔点和有序温度,从而使合金的使用温度达到９００℃以上。该体系合金显示出来的潜力具有代替Ｎｉ基合金的趋势。     

工艺参数对真空吸铸TiAl基合金连杆铸造过程的影响

本文利用底漏式真空吸铸方法制备TiAl合金汽车发动机连杆铸件,并研究了吸铸工艺参数对铸造过程的影响.分别采用了金属型芯金属模具、陶瓷芯金属模具以及陶瓷型壳进行性吸铸实验,研究了不同的吸铸参数对连杆铸件的成形性影响.得到了TiAl合金底漏式真空吸铸的优化工艺参数,初步获得了形状完整的连杆件.     

Environmental Effects on the Room Temperature Ductility of a TiAl Based Alloy

The effects of different environments and strain rates on the room temperature ductility of a TiAl based alloy with the composition Ti-46Al-2Cr-0.2Si-0.1Nd have been investigated in this paper. The results show that the TiAl based alloy is susceptible to environmental embrittlement at room temperature. The tensile ductility of the TiAl based alloy in difFerent test environments decreases in the sequence of oxygen> air>hydrogen>argon saturated with water vapor. The ductility is also sensitive to strain rate. It increases with increasing strain rate when tested in hydrogen gas. Both H2O and H2 cause environmental embrittlement, with the former being a more potent embrittler