【作者】 聂存珠；

【导师】 赵乃勤；

【作者基本信息】 天津大学 ， 材料学， 2004， 硕士

【摘要】 本文利用机械合金化-粉末冶金法制备了体积分数为 10%和 20%的 SiC 颗粒增强 6061 铝基复合材料。研究了机械合金化过程中粉末的形貌微观结构和性能的变化。考察了机械合金化-粉末冶金制备的 SiCp/6061Al 复合材料经烧结、固溶处理后，时效温度和时效时间对材料性能的影响，并探讨了其时效强化机理；研究了 SiCp/6061Al 复合材料在不同温度下的摩擦磨损特性，并对其磨损机理进行了初步探讨。 研究结果表明，机械合金化工艺可以改善 SiC 颗粒在基体中分布的情况。SiC颗粒和 6061Al 粉在机械合金化过程中发生增强体的破裂-基体的塑性变形、加工硬化、冷焊合-增强体颗粒嵌入合金基体-SiC 颗粒的均匀分布几个过程。 SiC 颗粒的加入不会改变基体合金的时效沉淀顺序，但复合材料中大量存在的位错及界面为β′形核提供机会，使得人工时效时达到峰时效所对应的时间提前。自然时效达到峰时效的时间比人工时效的长，而且所达到峰时效的硬度值较人工时效的硬度值的低。复合材料界面的透射电镜照片表明，采用机械合金化-粉末冶金法制备的复合材料的界面平直、干净，没有界面化学反应物产生。 SiCp/6061Al 复合材料的耐磨性能优于基体 6061Al 合金，并且随着 SiC 颗粒含量增加，发生严重磨损所需载荷明显增大。室温摩擦时，SiCp/6061Al 复合材料表面会形成由铁元素、基体合金和破碎了的 SiC 颗粒组成的机械混合层。复合材料的磨损机制与机械混合层的形成有很大关系。在高温摩擦时，低于 150℃时，6061Al 合金的磨损量小于 SiCp/6061Al 复合材料的磨损量，但在 200℃时，6061Al 磨损量急剧增大，大于 SiCp/6061Al 复合材料的磨损量。更多还原

【Abstract】 SiC particle reinforced 6061 aluminum matrix composites were fabricated by themechanical alloying (MA) and the powder metallurgy (P/M) technique with 10vol%and 20vol% SiC particles. The microstructure and property of the powders wereinvestigated at different period of MA processing. The effect of the aging temperatureand aging time on the property of the composites, which were prepared by MA ,sintering and solid-solution treatment, were investigated. The aging-hardeningmechanism of the SiCp/6061Al composites was also discussed. The tribological andwear property of the SiCp/6061Al composites were investigated at differenttemperature, and the wear mechanism of the SiCp/6061Al composites waspreliminarily analysised.The result showed that several steps happened during MA’s processing: plastictransformation of matrix alloy, fracture of reinforcement, work-hardening of matrixalloy, cold-welding, formation of lamination structure and uniform distribution of SiCparticles in matrix. A homogeneous distribution of SiC particles achieved by MAtechniques.There was no change of the sequence of precipitation of composites by addition ofSiC particle compared with that of unreinfored alloys during aging. But, an obvioushardening effect can be observed in the SiCp/6061Al composites resulting from theintroduction of numerous dislocation. Duration of peak-aging of the sample aged atroom temperature (Natural Aging, NA) was 48h, longer than that of the sample ofaged at a higher temperature (Artificial Aging, AA). The peak-microhardness of NAsample was lower than that of AA sample’s. The TEM morphology of 10MMCexhibited that interface of Al-SiC had a “cleaned” bonding and had no evidence ofchemical reaction product at the interface.The SiCp/6061Al composites have better wear resistance compared with that of 6061alloy. The wear resistance improved with increasing of the volume fraction of SiCparticles. At room temperature, good wear resistance of SiCp/6061Al compositessamples achieved by the addition of SiC particles was induced by the formation of themechanically mixed layer (MML). It was showed that the wear mechanism ofSiCp/6061Al matrix composites was related to the formation of MML rubbed againstthe iron , 6061Al exhibited a slighter wear mass loss than that of SiCp/6061Al<WP=4>composites below 150℃. At 200℃, the wear mass loss of Al increased dramaticallythan that of the SiCp/6061Al composites.更多还原