【作者】 王辉虎；

【导师】 许伯藩；

【作者基本信息】 武汉科技大学 ， 材料学， 2003， 硕士

【摘要】 颗粒增强金属基复合材料具有重量轻、比强度与比刚度高、剪切强度大等优点，因而被广泛应用于航空航天领域和汽车配件、体育用品等行业，其制造方法一般分为外加法与内生法。但外加法存在着诸如颗粒偏聚、润湿性差、界面强度结合低等缺点，而内生法由于增强颗粒是在基体内部原位反应生成，因此能克服外加法的缺点，但同时内生法所制备的金属基复合材料的成本太高、原位反应不易控制等缺点制约了复合材料的扩大应用，因此发展性能优异复合材料的出路在于寻找降低成本以及控制原位反应的措施。 采用廉价氧化物与Al的置换反应来制备Al₂O₃颗粒增强铝基复合材料的方法是目前的研究热点。但大部分的研究集中在单一氧化物与Al的置换反应生成增强颗粒Al₂O₃的方法上，研究表明，只有CuO／Al反应体系在Al熔点以上不高的温度范围能稳定生成颗粒，但同时CuO／Al反应过于剧烈，属于燃爆反应，不易控制。Al与其它单质氧化物反应虽然满足吉布斯自由能条件，但反应很慢，即在动力学上满足不了反应条件。因此，本研究采用多种氧化物CuO、TiO₂、SiO₂、同时与Al发生原位反应弥补了单质氧化物与Al反应的不足，发挥了各自氧化物的优点，控制了剧烈的铝热反应，扩充了原位反应的热力学体系。 本文研究了四种原位反应体系：CuO／Al、CuO+SiO₂／Al、CuO+TiO₂／Al、CuO+SiO+₂+TiO₂／Al，并对由这四种原位反应体系所制备的铝基复合材料的微观组织、布氏硬度、耐磨性能以及拉伸力学性能作了分析与检测，讨论了不同氧化物配比以及不同氧化物的混合对复合材料性能的影响，研究了氧化物与Al发生置换反应的热力学与动力学机理。 实验结果表明采用多种氧化物原位反应法合理调配了不同反应的绝热温度，控制了CuO与Al剧烈的铝热反应，同时促进了其它单质氧化物与Al反应，使其能自我维持进行下去。多种氧化物所制备的铝基复合材料比单一氧化物制备的复合材料的组织细小，减少了CuAl₂相的含量，使其无法形成致密的网状相，增强相陶瓷颗粒均匀分布于铝基体内部，强化了铝基体。 在相同的实验工艺条件下，CuO粉末与其它氧化物粉末的质量比为3：1时，原位反应比2：1时彻底，持续时间较长，所制备铝基复合材料微观组织均匀细小。在四种原位反应体系中，CuO+SiO₂+TiO₂／Al原位反应过程中被置换出来的金属元素Ti细化了基体组织，并起到了固溶强化的作用，所制备的复合材料的微观组织与机械性能明显优于CuO+SiO₂／Al与CuO+TiO₂／Al原位反应体系所制备的复合材料。在本实验条件下，CuO+TiO₂／Al原位反应体系所制备的复合武汉科技大学硕士论文材料中第二相增强粒子A13Ti尺寸较大且分布不均匀，不利于复合材料性能的提简。 氧化物与Al的原位反应是一个反应原子的扩散过程，反应在氧化物与Al的界面上进行并形成完整的反应膜，然后合成反应通过反应原子的双向扩散在界面上进行。更多还原

【Abstract】 Particulate reinforced metal matrix composites possess several additional advantages such as light weigh high specific strength and stiffness great shear strength. So they are widely used in many general applications in spaceflight car fittings sports goods areas. According to the difference of the wild phase’s formation, the composite’s manufacturing method can be divided into traditional way and in situ way. The main disadvantages of the traditional way are the particles’ conglomeration, bad compatibility between wild phase and matrix, low interfacial strength and so on. In situ way has overcome these disadvantages because the wild phase is formed in matrix. However, in situ way also has its disadvantages. It costs more than the traditional way and it is hard to control the process of the reaction. These disadvantages have led to some limitations of the composites’ production and research. Therefore, the developing orientation of in situ composites is to search the means of lowering the cost and controlling the process of in situ reaction.There has been an increasing interest in the production of particulate reinforced aluminum matrix composites by the replacement reaction between low-cost oxides and Al. But most of the researches focus on the reaction of single oxide and Al to form wild phase Al2O3. These researches show that only CuO/Al reaction system can produce Al2O3 particles steadily. However, the reaction is very drastic and it belongs to blast reaction. The replacement reactions between other oxides and Al are very slow. It indicates that they don’t accord with the dynamic conditions. So this research proposes a new idea to fabricate aluminum matrix composites by combining several oxides to react with Al at the same time. This idea overcomes the shortages of CuO/Al system and the other single oxide system. It extends in situ reaction system.In this paper, four reaction systems: CuO/Al, CuO+SiO2/Al, CuO+TiO2/Al, CuO+SiO2+TiO2/Al have been studied. The composites are fabricated by the four reaction systems. The microstructures hardness grinding performances and mechanical properties of the composites have been analyzed. This paper also discusses the influences of quality ratio and mixture of different oxides to the composites’ properties. At the same time, the thermodynamic principles and principles of dynamics have been studied.The experimental results show that in situ reaction between several oxides and Al balances adiabatic temperature and controls the drastic reaction between CuO and Al. At the same time, this kind of in situ reaction also accelerates the other replacementreactions and makes them react till to the end. The microstructures of composites fabricated by this research are much smaller than the ones fabricated by single oxide. The quantity of CuAl2 phase is lessened largely and it doesn’t form messy phase. The ceramic particles distribute in the aluminum matrix equably and strengthen the matrix.Under the same experimental conditions, the reaction is more thorough and the durative time of the reaction is also longer when the quantity ratio of CuO to the other oxides is 3:1 than when it is 2:1. In CuO+SiO2+TiO2/Al reaction system, the element Ti which is replaced in the reaction makes the microstructure of composite thin and the matrix strong. The mechanical properties of the composites fabricated by this reaction system are much finer than the ones fabricated by CuO+SiO2/Al and CuO+TiO2/Al reaction system. In CuO+TiO2/Al reaction system, the wild phase Al3Ti is very large and it is disadvantageous to the improvement of composites’ properties.In situ reaction between oxide and Al is a diffusing process of reaction atoms. In this process, an integrated reaction membrane is engendered in the interface of oxide and Al firstly. Then the synthesis reaction holds on through the reaction atoms’ diffusion.更多还原