颗粒增强Fe3Al基复合材料的制备和性能

用熔铸法制备了ＳｉＣ,Ａｌ２Ｏ３和ＴｉＢ２颗粒增强Ｆｅ－２８Ａｌ－５Ｃｒ基复合材料,研究了材料的微观组织和力学性能,结果表明,Ａａ２Ｏ３在Ｆｅ３Ａｌ中的化学稳定性很好,ＴｉＢ２与基体发生了部分反应,ＳｉＣ与基体的反应严重,复合材料在室温和高温下的力学性能的变化说明,上述颗粒的加入使材料的强度较大幅度的提高,塑性有所下降。     

TiC-Al2O3-Fe金属陶瓷的自蔓延高温合成研究

通过自蔓延高温合成结合准热等静压法（ＳＨＳ／ＰＨＩＰ）制备出了致密度为９７．７％的ＴｉＣ－Ａｌ２Ｏ３－２０Ｆｅ金属陶瓷（ＴＡＦ２０）。分析了金属陶瓷的相组成、微观组织及性能。结果表明：金属陶瓷由ＴｉＣ,Ａｌ２Ｏ３陶瓷颗粒和Ｆｅ粘结相组成;粘结相中Ｆｅ与Ａｌ２Ｏ３之间的界面光滑,与ＴｉＣ之间有一薄的扩散层;ＴＡＦ２０金属陶瓷的抗弯强度和抗压强度分别为８９０ＭＰａ和１８．４ＧＰａ。     

TiC—Al2O3—Fe金属陶瓷的蔓延高温合成研究

通过自蔓延高温合成结合准热等静压法（ＳＨＳ／ＰＨＩＰ）制备出了致密度为９７．７％的ＴｉＣ－Ａｌ２Ｏ３－２０Ｆｅ３合金陶瓷（ＴＡＦ２０）,分析了金属陶瓷的相组成、微观组织及性能。结果表明：金属陶瓷由ＴｉＣ,Ａｌ２Ｏ３陶瓷颗粒和Ｆｅ粘结相组成;粘结相中Ｆｅ与Ａｌ２Ｏ３之间的界面光滑,与ＴｉＣ之间有一薄的扩散层;ＴＡＦ２０金属陶瓷的抗强度和抗压强度分别为８９０ＭＰａ和１８．４ＧＰａ。     

代位原子在Fe3Al亚点阵中的占位与合金的塑性

采用中子衍射法测定了Ｃｒ、Ｍｏ、Ｔｉ、Ｎｉ、Ｍｎ、Ｓｉ等代位原子在ＤＯ３结构Ｆｅ３Ａｌ亚点阵中的原子占位，并从解离能角度探讨了原子对之间的相互作用及合金室温塑性的影响，结果表明：Ｃｒ、ＭＯ、Ｔｉ都占据了Ａｌ原子的次近邻位置，替代Ｆｅ原子；Ｎｉ、Ｍｎ占据Ａｌ原子的最近邻位置，（Ｓｉ＋Ａ）当量成分以内的Ｓｉ原子替代占据Ａｌ原子的位置，由于Ａｌ－Ｃｒ原子对的结合能低于Ｆｅ－Ａｌ，ＡＬ－Ｍｏ用Ａｌ－Ｔｉ对     

原位生长陶瓷相增强Al基复合材料的界面、微观结构及性能

本文对原位生长Ａｌ_４Ｃ_３与外加ＳｉＣ颗粒混杂增强Ａｌ（Ａｌ_４Ｃ_３·ＳｉＣ／Ａｌ）和原位生长Ａｌ_２Ｏ_３、ＴｉＢ_２颗粒混杂增强Ａｌ（Ａｌ_２Ｏ_３·ＴｉＢ_２／Ａｌ）两种复合材料的界面、微观结构和性能进行了研究。原位生长陶瓷相在基体中呈均匀分布。Ａｌ_２Ｏ_３和ＴＩＢ_２为尺寸１０ｎｍ～２μｍ的颗粒，Ａｌ_４Ｃ_３为长度０．２μｍ，直径０．０２μｍ的棒状单晶体。原位陶瓷相和Ａｌ基体之间的界面是清洁的，不存在中间过渡层。Ａｌ_４Ｃ_３和Ａｌ之间可存在的取向关系．Ａｌ_２Ｏ_３和ＴｉＢ_２粒子与Ａｌ之间不存在取向关系。两种复合材料都表现出优于ＳｉＣ_ｗ／Ａｌ复合材料的强度。     

镍硼镀层对陶瓷与金属联接的影响

采用自催化镀方法对Ａｌ２Ｏ３陶瓷表面进行３Ｎｉ－Ｂ镀层金属化处理，然后，把金属化的Ａｌ２Ｏ３分别和Ｎｉ，Ｆｅ－Ｎｉ合金组成偶对，进行了固相压力扩散焊，并通过组织分分析对界面区的固相反应进行研究。结果表明，经特殊预处理的９９％Ａｌ２Ｏ３陶瓷，其表面镀层Ｎｉ－Ｂ型基体的结合强度可达２５０ＭＰａ以上，镀层呈非晶态，而热处理可完全晶体化。Ｎｉ－Ｂ／Ｎｉ（Ｆｅ－Ｎｉ）对。界面消失，成分完全均匀；Ａｌ２Ｏ３／     

Al-TiO2-C-Ti-Fe体系反应过程研究

采用ＤＳＣ和ＸＲＤ对不同Ｆｅ含量Ａｌ－ＴｉＯ２－Ｃ－Ｔｉ－Ｆｅ体系的燃烧反应过程进行了研究。结果表明,Ａｌ－ＴｉＯ２－Ｃ－Ｔｉ－Ｆｅ体系的反应是分步进行的。在高温区以金属间化合物的分解及Ｔｉ、Ｃ反应为主;在低温区则随着Ｆｅ含量的不同存在不同的反应：Ａｌ－ＴｉＯ２－Ｃ－Ｔｉ以Ａｌ、Ｔｉ的反应为主,Ａｌ－ＴｉＯ２－Ｃ－Ｔｉ－２０ｗｔ％Ｆｅ以Ａｌ、Ｔｉ及Ａｌ、Ｆｅ反应为主,同时还存在Ａｌ、ＴｉＯ２及Ｆｅ、Ｔｉ反应,而Ａｌ－ＴｉＯ２－Ｃ－Ｔｉ－５０ｗｔ％Ｆｅ则以Ｆｅ、Ａｌ和Ｆｅ、Ｔｉ反应为主。     

内生TiC颗粒增强NiAl基复合材料的初步研究

用ＨＰＥＳ工艺合成了２０ｖ．％ＴｉＣ颗粒增强的ＮｉＡｌ基复合材料，其维氏硬度、压缩屈服强度都比单相ＮｉＡｌ有大幅度提高。特别是室温和１０００℃以上，屈服强度比基体提高近二倍，室温塑性也优于单相ＮｉＡｌ。     

颗粒增强TiAl基复合材料及其Si的韧化作用研究EI

运用ＸＤ工艺制备了颗粒增强ＴｉＡｌ基复合材料。增强颗粒均匀分布于ＴｉＡｌ基体中并细化ＴｉＡｌ合金。通过在ＴｉＢ_２／ＴｉＡｌ、ＴｉＣ／ＴｉＡｌ复合材料中加入适量的Ｓｉ，颗粒增强ＴｉＡｌ基复合材料的室温延性得到了改善。     

陶瓷薄膜与金属间的浸润性及其界面的研究

本文在对 ＴｉＮ、ＴｉＣ陶瓷薄膜与金属 Ａｇ、 Ｃｕ、 Ｎｉ、 Ｆｅ间的浸润性测量的基础上，用扫描电子显微镜（ＳＥＭ）、电子探针（ＥＰＭＡ）对其界面进行了观察。结果表明：浸润性较差的Ａｇ、Ｃｕ与ＴｉＮ、ＴｉＣ的界面平整，几乎没有发生相互扩散和化学反应；而浸润性较好的 Ｆｅ、Ｎｉ与 ＴｉＮ、ＴｉＣ的界面有明显的扩散和化学反应现象沿着ＴｉＮ、ＴｉＣ的晶界扩散；薄膜部分甚至全部溶入金属中。ＴｉＣ薄膜与Ｆｅ的界面反应程度大于ＴｉＮ 薄膜。     

原位TiB/Ti复合材料的熔铸制备及其显微组织

结合Ti-B-Al体系的热力学及Ti-B相图,提出了可制备薄壁、复杂形状原位自生钛基复合材料构件的SMIF工艺.采用XRD、SEM和TEM等手段研究用该工艺制备的复合材料的相组成和显微组织.结果表明,钛基复合材料中生成了TiB增强相,且在基体中分布均匀,呈短纤维状;并且Al的加入使得TiB相具有较高的长径比,最高可达110.TiB增强相/基体界面清洁、无污染.受熔模精铸陶瓷型壳的激冷作用,钛基复合材料铸锭表层中TiB相垂直于铸锭的表面分布.与基体合金相比较,钛基复合材料的力学性能有了很大程度的提高.     

Microstructure of TiB Whisker Reinforced Ti Matrix Composite

The composite of Ti matrix with TiB whisker reinforcement has been successfully fabricated. The content of TiB whisker in Ti matrix can reach about 30 vol. pct. Metallographic examination,morphology and microstructure of TiB whisker, interface structure between TiB whisker and Ti matrix were investigated using optical microscope, SEM, TEM and HREM technology. The diameter distribution of TiB whisker is from 0. 1 μm to 3.5 μm and the aspect ratio of TiB whisker is from 10 to 20. The cross-section of whisker is generally polygon. Because of good compatibility between TiB whisler and Ti matrix it is identified that there is no obvious interaction of Ti matrix with Ti B reinforcement and TiB whisker reinforced Ti matrix composites have excellent elevated properties.     

热等静压碳/铝复合材料的断口和界面的研究

采用热等静压(HIP)工艺,把包复在真空玻璃容器内的C/Al复合丝热压成致密的C/Al复合材料。用扫描电镜(SEM)观察到复合材料的低强度平断口和界面反应层。运用透射电镜(TEM)和X射线能谱仪(XES)观察和确定界面的形貌和成分,发现界面分成层状,界面层的TiB₂向两边扩散,而纤维和基体的成分则通过界面而互相扩散。另外,还用电子衍射技术(EDT)研究了界面的晶体结构,确定它的相组成为TiO₂、TiC、TiB₂、γ-Al₂O₃及Ti、B和C等。采用俄歇电子能谱(AES)分析了界面区的化学组分,并运用二次离子质量谱(STMS)确定出界面的化学组成,除发现Al₄C₃,与EDT的结果基本一致。      

TiB2-Cu基复合材料的燃烧合成研究

通过燃烧合成工艺制备了TiB2-40%Cu(质量分数）基复合材料，对复合材料的反应热力学、相组成以及微观组织进行了研究。热力学计算结果表明TiB是最稳定的相，中间相Ti-Cu化合物最终转变为TiB2相；XRD结果显示复合材料的相组成为TiB2相和Cu相，没有生成其他中间相；微观组织观察表明，合成产物组织致密，增强体TiB2陶瓷颗粒尺寸细小，形貌主要呈近等轴状和块状，Cu作为金属粘结剂将TiB2陶瓷颗粒相互连接在一起，Cu的存在促进了燃烧合成过程中材料的致密化行为。Cu的加入使TiB2-Cu基复合材料的致密度、弯曲强度和断裂韧性较TiB2纯陶瓷均有大幅度提高，材料的韧化机制为裂纹尖端塑性钝化机制。     

铸态Al-4. 5Cu/TiB2 复合材料组织和性能的研究

提出一种新型的原位反应合成工艺——熔体反应法, 以TiO₂、H₃BO₃、Na₃AlF6 和Al-Cu 合金为原材料, 采用熔体反应法制备了低成本的内生颗粒增强Al-4. 5Cu/TiB₂ 复合材料。TiB₂ 颗粒细小, 平均尺寸为0. 93 Lm, 均匀分布于基体之中, 与基体结合良好。当TiB₂ 的含量为10 vo l% 时, 复合材料的抗拉强度为416. 7M Pa, 屈服强度为316.9M Pa, 延伸率为3. 3%。      

Mechanical property under high dynamic loading and microstructure evaluation of a TiB2 particle-reinforced stainless steel

The incorporation of low density, high modulus ceramic particles into a steel matrix is a potential route to improve the mechanical performance of steels. A powder metallurgy, mechanical blending route has been adopted to produce a homogeneous distribution of TiB2 particles in a 316L stainless steel matrix. The resulting composite showed large increases in both the compression and the tensile strength when compared to the unreinforced alloy. The compression strength was measured under both quasistatic and dynamic conditions. Tensile strength was measured only under quasistatic conditions. Dynamic compression tests were performed at temperatures of 200 and 400 °C. Metallographic investigations have been performed on the specimen in the initial status and after a deformation. Fracture surfaces were studied in a scanning electron microscope to allow more detailed assessment of fracture mechanisms.     

Interfacial reactions in a Ti-6Al-4V based composite: role of the TiB2 coating

The characterization of TiB₂/C-coated SiC fibres and their interface region in a Ti-6Al-4V based composite has been performed by using scanning electron microscopy (SEM), energy-dispersion X-rays (EDX) and Auger electron spectroscopy (AES). The features of the as-received fibre and the reactivity between fibre and matrix occurring during preparation of the composite have been studied in this paper. The interaction of the TiB₂ external coating of the fibre with both the adjacent carbon layer and the titanium-based matrix is already appreciable in the as-received composite: TiB needles grow from TiB₂ towards the matrix and a new layer containing C, Ti and B appears between TiB₂ and C. The thicknesses of the original carbon and TiB₂ fibre coatings decrease in the composite from 1000 nm to 400 and 800 nm, respectively. The TiB₂ inhibits the reaction between SiC and Ti: there is no evidence of Si _x Ti _y brittle phases.     

On the Effects of Surface Treatments on the Mechanical Strength of Carbon Fibres

TiB2, pyrolytic carbon (Cpyr) and Cpyr + TiB2 double layer coatings have been envisaged as potential protective coatings to prevent the deleterious interface reactions between the carbon fibre and the aluminium matrix during composite manufacturing. These coatings have been obtained by low pressure chemical vapour deposition on T800H carbon fibre yarns. In spite of a 20 % increase in the coated monofilaments tensile strength observed for very thin Cpyr coatings, a strength decrease as a function of the coating thickness is recorded for single Cpyr or TiB2 layers. For the TiB2 coatings, this decrease fits well with Ochiai's model which simulates the notch effect induced by a cracked brittle layer. Concerning the Cpyr coatings, a lower damaging effect is observed as compared to TiB2, it may be explained by the difference between the Young's moduli of both layers. Although the initial fibre properties are not perfectly maintained in the case of the double layer, the crack deviation role of the Cpyr coating succeeds in preserving the coated fibres from the TiB2 notch effect, thus leading to a noticeable strength increase.     

Fabrication of Titanium Diboride-Cu Composite by Self-High Temperature Synthesis plus Quick Press

1. IntroductionTitanium diboride ceramic has some special proper-ties, such as high melting points, high hardness, highelectrical and thermal conductivity. These special prop-erties make it has a great potential to be used as contactmaterials. However, this application is still limited forpoor sinterability and brittle of TiB2[1~3]. To improve itssinterability and toughness, some metals were selected asadditives for liquid phase sintering of TiB2. Metals likeFe, Co and Ni were studied in m…     

As received Ti–6AI–4V/σ-SiC fibre composite

Abstract

A Ti–6Al–4V/σ (SM 1240) composite prepared by diffusion bonding has been studied in the as received condition, using Auger electron spectroscopy, transmission electron energy loss spectroscopy, and scanning electron microscopy. The SiC based σ fibre has a tungsten core, and a duplex coating of carbon (adjacent to the SiC deposit) and TiB_x. It is shown that boron from the TiB_x layer diffused into the matrix and formed TiB needles. Carbon was detected in the TiB_x layer and was present in elemental free form. A continuous SiO₂+ carbon layer was detected at the SiC/carbon layer interface. Analysis of in situ fracture composite surfaces in an Auger spectrometer has shown that the tensile failure was initiated within the carbon layer or at the TiB_x/matrix interface. An oxide layer detected at the TiB_x/matrix interface influenced the fracture behaviour of the composite.

MST/2027