铸造SiC_p/Al-Si复合材料中的“界面Si”行为

采用ＴＥＭ 研究了ＳｉＣ／ＡｌＳｉ 复合材料, 提出了“界面Ｓｉ”的概念。由于与增强体ＳｉＣ 不润湿, 初生α（Ａｌ） 相不在ＳｉＣ 颗粒上形核并对其发生排斥。（Ａｌ＋ Ｓｉ） 共晶体中的共晶领先相Ｓｉ 优先在ＳｉＣ表面上形核、长大, 形成界面Ｓｉ, 并形成大量ＳｉＣ／Ｓｉ 界面。ＳｉＣ／Ｓｉ 界面“干净”、平直, 结合紧密, 其中未发现任何界面相。在个别ＳｉＣ／Ａｌ 界面上析出了二次Ｓｉ。     

铸造SiCp／Al—Si复合材料中的“界面Si”行为

采用ＴＥＭ研究了ＳｉＣ／Ａｌ－Ｓｉ复合材料,提出了“界面Ｓｉ”的概念。由于与增强体ＳｉＣ不润湿,初生α（Ａｌ）相不在ＳｉＣ颗粒上核并对其发生排斥。（Ａｌ＋Ｓｉ）共晶体中的共晶领先相Ｓｉ优先在ＳｉＣ表面上形核、长大,形成界面Ｓｉ,并形成大量ＳｉＣ／Ｓｉ界面。ＳｉＳｉ界面“干净”、平直、结合紧密,其中未发现任何界面相。在个别Ｓｉ／Ａｌ界面上析出了二次Ｓｉ。     

Al/SiC界面结合机制的研究现状(续)

2 .3　Ａｌ/ＳｉＣ界面反应机理一般认为在ＳｉＣ/Ａｌ系统中 ,Ａｌ4 Ｃ3的形核通过两个步骤进行 :即ＳｉＣ溶解于熔融Ａｌ中 ,然后与Ａｌ发生如式⑴的反应 ,基本上是溶解、扩散和化合的过程 ,Ａｌ/ＳｉＣ界面属于既有溶解又有反应结合的混合型界面。ＳｉＣ的溶解似乎是一个择优过程 ,当ＳｉＣ与Ａｌ液接触时 ,界面能具有各向异性的特点 ,为了减少系统的界面能 ,ＳｉＣ表面高能量位置发生溶解 ,从而产生台阶 ,使与基体结合的ＳｉＣ晶面是低能量、低能数晶面〔2 9〕,实验结果也表明ＳｉＣ的溶解是不均匀的〔2 8〕,但对于Ａｌ/ＳｉＣ界面反应…     

液相搅拌铸造法制备SiCp/Al复合材料的力学性能

对旋涡搅拌铸造法制备的ＳｉＣｐ／Ａｌ复合材料的界面和力学性能进行了分析研究,结果表明,ＳｉＣｐ／Ａｌ的界面结合为性能良好的冶金结合,ＳｉＣ颗粒能提高铝基体的拉伸强度,同时显著提高铝基体的室温硬度与高温硬度。     

铝—石墨界面反应对石墨,碳化硅混杂增强铝基复合材料摩 …

研究了石墨（Ｇｒ）－铝界面反应对Ｇｒ,碳化硅（ＳｉＣ）混杂增强铝基复合材料（Ｃｒ＋ＳｉＣ／Ａｌ摩擦磨损性能的影响。在６３０℃下对ＳｉＣＡｌ和混杂复材料分别加热保温了４,８,１２,１６ｈ。硬度试验和透射电镜分析说明,随热处理时间的延长,Ｇｒ－Ａｌ界面反应物增加,而ＳｉＣ－Ａｌ几乎没有发生界面反应。用热处理后的混杂复合材料试样进行了干磨损试验。结果透明,随着热处理时间的延长,混杂复合材料摩擦系数升高,     

SiC/TiAl扩散连接接头的界面结构及连接强度

对常压烧结的ＳｉＣ陶瓷与ＴｉＡｌ金属间化合物进行了真空扩散连接。采用扫描电镜、电子和Ｘ射线衍射分析等确定了反应产物的种类和接头的界面结构,并用拉剪试验评价了接头的连接强度。研究结果表明：ＳｉＣ与ＴｉＡｌ扩散连接中生成了ＴｉＡｌ２、ＴｉＣ和Ｔ５Ｓｉ３Ｃｘ三种上,接头的界面结构为ＳｉＣ／ＴｉＣ／（ＴｉＣ＋Ｔｉ５Ｓｉ３Ｃｘ）／ＴｉＡｌ。在１５７３Ｋ和１．８ｋｓ的连接条件下,接头室温剪强度达到２４０ＭＰａ     

表面复合铸造SiC／Al显微组织及界面现象初探

采用负压铸型在铝铸件表面形成一层ＳｉＣ／Ａｌ复合材料层，初步探讨了复合层的显微组织和ＳｉＣ－Ａｌ界面结合，表明复合层中，ＳｉＣ粒子分布均匀，与基体合金界面结合良好。     

SiCp/LD2Al合金复合材料电弧焊的焊接性

采用脉冲钨极氩弧焊焊接了ＳｉＣｐ／ＣＤ２Ａｌ复合材料,并用Ｘ射线衍射、光镜、电镜及ＭＴＳ－８１０试验机对焊缝的组织及性能进行了分析,结果表明,通过焊前去氢处理及填充Ａｌ－Ｓｉ焊丝,可以解决ＳｉＣｐ／ＬＤ２Ａｌ复合材料电弧焊中的界面反应、气孔及裂纹等总理２,并能获得性能良好的接头。     

（Al2O3—SiO2）sf／Al—Si复合材料的界面反应

本文对液体浸渗法制备的（Ａｌ２Ｏ３－ＳｉＯ２）ｓｆ／Ａｌ－Ｓｉ复合材料界面反应进行了研究,采用化学反应涂层处理的方法,在Ａｌ２Ｏ３－Ｓｉｏ２短纤维表面涂覆一层非晶态的ＳｉＯ２,从而改变纤维与基体的结合方式,使界面由溶解结合转变为反应结合,并产生了ＭｇＡｌ２Ｏ４界面反应相,ＭｇＡｌ２Ｏ３相的大小和分布对复合材料的力学性能产生重要影响,ＭｇＡｌ２Ｏ４在界面呈非连续的块状分布时,复合材料强度最高,当界在     

晶须增强Al－8．5Fe－1．3V－1．7Si复合材料及晶须增强效果的评价

采用粉末冶金法在较高的温度下制备了ＳｉＣ，Ｓｉ_３Ｎ_４和Ａｌ_（１８）Ｂ_４Ｏ_（３３）晶须增强Ａｌ－８．５Ｆｅ－１．３Ｖ－１．７Ｓｉ耐热铝合金复合材料，山于采用不含Ｍｇ的基体避免了Ａｌ_（１８）Ｂ_４Ｏ_（３３）晶须界面上出现界面反应和Ｓｉ_３Ｎ_４，ＳｉＣ晶须界面上出现的界面生成物，所以所有晶须界面都是清洁的．加入晶须可以明显提高材料的强度和模量，三种晶须的增强效果依次为ＳｉＣ，Ｓｉ_３Ｎ_４和Ａｌ_（１８）Ｂ_４Ｏ_（３３）．这类复合材料的强度随温度的升高呈线性下降，其使用温度可比ＳｉＣ_ｗ／２０２４Ａｌ复合材料提高５０－１００℃     

Investigation of interfacial bonding between Na2O–B2O3–SiO2 solder and silicon carbide substrate

Abstract

The interfacial characteristics of the SiC/glass solder/SiC joining part were investigated by means of thermodynamic and wetting behaviour calculation, microstructure observation, chemical structure and element analysis. The results of wavelength dispersive spectroscopy linear scan across the joint showed a relatively low increase in sodium content at the interfaces, which indicated that the sodium silicates in glass could react with silicon carbide substrate at the joining temperature, but it is not the reason for the good bonding between SiC and the interlayer. The mechanism of the good interfacial bonding lies in the formation of oxycarbide phase at the interface.     

C/Ti/Cu interfacial reaction in SiC<Subscript>f</Subscript>/Cu composites

Continuous SiC fiber reinforced copper matrix(SiCf/Cu) composites were prepared by fiber coating method,and Ti6Al4V interlayer was introduced as an interfacial modification coating to improve the interfacial bonding strength.The interfacial reaction characteristics were investigated by transmission electron microscopy(TEM).The results show that nearly all the titanium atoms reacted with the carbon coating of SiC fibers to form two layers of TiC.Also,a thin copper layer that is sandwiched between these two layers was detected.No Ti-Cu interfacial reaction product was observed.The formation process of the interfacial reaction along with its mechanism was discussed.     

Chemical kinetic studies on interfacial reaction in SCS-6 SiC/Ti matrix composites

Interfacial reaction and its mechanism of SiC/Ti composite were revealed by chemical kinetic studies. A two-step dynamic model of interfacial reaction in SCS-6 SiC/Ti composites was built up, and the rate constant and the activation energy of the interfacial reactions were obtained based on the quantum chemistry calculation. The results show that the first step, in which the atomic Ti, C and Si are decomposed from Ti matrix and SiC fiber, respectively, is a rate-determined step because the activation energy of the step is much larger than that of the second one in which deferent interfacial reaction products form. The theoretically predicted result of the interfacial reaction is coincident with that of experimental observation.     

SiCf/Ti-6Al-4V复合材料的界面研究

采用扫描电镜、透射电镜和X射线衍射仪研究了用中国制备SiC纤维增强的Ti-6Al-4V复合材料的界面反应,发现在SiC纤维的C涂层和Ti-6Al-4V基体之间形成的界面反应产物为细晶粒和粗晶粒的TiC,而无C涂层的SiCf/Ti-6Al-4V的界面反应产物,从SiC纤维到Ti-6Al-4V基体,依次为细晶粒的TiC+Ti5Si3、粗晶粒的TiC和Ti3SiC2.还测量了界面反应区厚度并讨论了界面反应机理.     

SiCf／Ti-6AI-4V复合材料的界面研究

采用扫描电镜、透射电镜和x射线衍射仪研究了用中国制备SiC纤维增强的Ti-6AI-4V复合材料的界面反应，发现在SiC纤维的C涂层和Ti-6AI-4V基体之间形成的界面反应产物为细晶粒和粗晶粒的TiC，而无C涂层的SiCf／Ti．6AI．4V的界面反应产物，从SiC纤维到Ti-6AI-4V基体，依次为细晶粒的TiC＋Ti5Si3、粗晶粒的TiC和Ti3SiC2。还测量了界面反应区厚度并讨论了界面反应机理。     

Effects of Mg content on microstructure and mechanical properties of SiCp/Al-Mg composites fabricated by semi-solid stirring technique

10%(volume fraction) SiCp/Al-Mg composites with different Mg contents were successfully fabricated by semi-solid mechanical stirring technique under optimum processing conditions.Effects of Mg content on microstructure and mechanical properties were studied by scanning electron microscopy(SEM),X-ray diffractometry(XRD) and transmission electron microscopy(TEM).The results indicate that SiC particles disperse homogeneously in Al-Mg matrix and interfacial reaction between Al matrix and SiC particles is effectively controlled.Distribution of SiCp reinforcement and interfacial bonding are improved by adding Mg.Additionally,the mechanical properties of composites are remarkably improved with the Mg content increasing.     

FABRICATION OF Ti/SiC MMCs BY VACUUM HOT PRESSING WITH AID OF HYDROGEN

1.IntroductionThemechbocalpropertiesofmetaJmatrircomposites(MMCs)arelargelycontrolledbythebounda-rystateofthematrir/fiberiliterfaCe,whichplaysanimport8ntroleinloadtransferinMMCs.TheinterfaCereactionproductsinc0ntinu0usSiCfiberreinforcedtitaulummatrircomp0sitesareusuallybrittleTi5Si3andTiC[1].Accordingt0Reevesetal'swork[z],areactionzoneatreinforcement/matririllterfacewiththicknessofm0rethan1pmresultedinseriousdegradation0ftheinterfaCestrengthandmechanicalpr0perties0fthecomposite.Therefor…     

Preparation and Interface Structures of Metal-encased SiC Composite Armors with Interpenetrating Structure

基于宏观有序多孔SiC陶瓷板的制备和对其进行金属铸造的复合技术制备了一种具有三明治互穿结构的新型金属封装SiC陶瓷复合装甲.采用SEM和EDS手段对3种复合装甲中金属(钢和钛合金)/陶瓷界面的显微结构和元素组成或分布进行了分析.相对优良的界面结合的获得与界面相互作用和铸造冷却过程中陶瓷主要受压应力的状态密切相关.界面结构取决于采用的金属材料(包括主体金属元素及其存在状态)和铸造工艺.     

SiCp/Al复合材料的离心熔渗法制备及其性能

研究了反应离心熔渗法制备高体积比SiCp／Al复合材料的工艺过程及其抗弯强度。结果表明：通过适当的粒度配比，可在低温、低离心力下熔渗制备组织均匀的高体积比SiCp／Al复合材料，SiC颗粒体积分数可达到63％；复合材料的强度在很大程度上依赖于SiC颗粒尺寸及界面反应程度，合适的界面结合及细SiC颗粒的掺入有利于复合材料强度的提高；基体热处理改变了SiC颗粒所受应力状态，提高了复合材料的强度，其最高值可达519MPa。     

SiCf/Ti-6Al-4V复合材料界面反应动力学

SiC纤维增强Ti基复合材料（SiCf／Ti）容易发生界面反应，从而影响其力学性能。开展界面反应和动力学的研究，对于SiCdTi复合材料的制备和服役具有指导意义。采用扫描电镜、透射电镜和X射线衍射分析了SICf／Ti-6Al—4V复合材料的界面反应及其动力学，发现SiC纤维的C涂层与Ti-6Al—4V反应形成粗晶粒的和细晶粒的TiC，长期高温热处理使得界面反应加剧，TiC层加厚，当C涂层完全消耗后，界面反应层中除了TiC外，还出现了Ti3SiC2。研究表明，界面反应层的加厚受元素扩散控制，服从抛物线规律，求出的动力学参数Q为268．8kJ／mol，k为0．0057m/s1/2。