原位al2o3颗粒增强6063铝基复合材料显微组织及力学性能研究.doc

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摘要 本文以6063Al 合金作为基体，采用6063Al-K2ZrF6-Na2B4O7体系及熔体反应法，通过设计反应体系和改变具体工艺参数以制备不同质量分数的Al2O3p/6063Al复合材料。通过对Al2O3p/6063Al复合材料显微组织观察、X射线衍射及能谱分析可知，熔体反应可以自发进行，复合材料中有Al2O3颗粒生成，尺寸介于400~800nm之间，颗粒基本呈米粒状或近球形；对6063Al-K2ZrF6-Na2B4O7剂反应体系的SEM照片分析表明，反应在850°C时反应生成的Al2O3颗粒呈米粒状或多边状，平均尺寸小于1μm，分布均匀，无明显反应副产物及副产物长大现象。因此850°C为制备Al2O3p/6063Al复合材料最佳反应时间；从颗粒在熔体中的界面能角度出发，分析了可以导致颗粒在熔体内发生再分布的推移现象，表明减小颗粒粒径、降低熔体粘度等方法可以改善颗粒在复合材料凝固过程中的分布状况。

通过对塑性变形处理前后Al2O3p/ 6063Al复合材料的金相显微组织研究结果表明：复合材料的大变形量的塑性变形由6063铝合金基体晶粒内部的滑移来进行，随着变形量的增大，基体晶粒和残留相沿塑性加工方向被拉长，沿加工垂直方向被压扁、破碎，最后趋于流线分布形成纤维组织；对塑性变形处理前后Al2O3p/ 6063Al复合材料的增强颗粒微观形貌和分布的观察发现，塑性变形前，Al2O3颗粒分布有一定的团聚现象，外观具有棱角，基体内存在一定的夹杂相。塑性加工后，Al2O3颗粒团聚得到明显改善，较大颗粒因受到剪切应力而破碎并呈现钝角化的趋势，夹杂相破碎并分散于基体中。

关键词：颗粒增强铝基复合材料，塑形加工，显微组织，力学性能

In situ Al2O3 particles reinforced aluminum matrix composites 6063 microstructure and mechanical properties

Abstract  In this paper, 6063Al alloy as the matrix, using 6063Al-K2ZrF6-Na2B4O7 system and melt

reaction, the reaction system and change through the design of specific process parameters to produce different concentrations Al2O3p/6063Al composites. By Al2O3p/6063Al composite microstructure morphology, X-ray diffraction and EDS analysis, the melt reaction can occur spontaneously, the composite particles generated in Al2O3, size ranged between 400~800nm, rice-like particles substantially or nearly spherical; for 6063Al-K2ZrF6-Na2B4O7 agent of the reaction system SEM photograph analysis indicated that the reaction at 850°C when the reaction of Al2O3 particles were rice-like or multilateral having an average size of less than 1μm, evenly distributed, no obvious reaction byproducts and byproducts grown phenomenon. Therefore, 850°C for the preparation Al2O3p / 6063Al composite optimum reaction time; from the grain boundary can angle in the melt, analyzes the phenomenon can lead to redistribution of the passage of particles in the melt occurs, indicating that the particle size is reduced reduce melt viscosity and other methods to improve the distribution of particles in the composite solidification process.

    By studying the results of metallurgical microstructure before and after the plastic deformation process Al2O3p/6063Al composites show: a large amount of deformation of composite plastic deformation by a 6063 aluminum alloy matrix grains to slip, with the increase of deformation, bent along the matrix grain and residual plastic processingdirection is elongated along the machine vertically flattened, broken, and finally tends tostreamline the formation of fibrous tissue distribution; reinforcing particles before and after the plastic deformation process Al2O3p/6063Al composite microstructure and observe the distribution of discovery, before the plastic deformation, Al2O3 particle size distribution have a certain agglomeration, the appearance of having corners, there are some mixed phase matrix. After the plastic processing, Al2O3 particle agglomerationsignificantly improved due to the larger particles subjected to shear stress and broken the trend and showed an obtuse angle, mixed with crushed and dispersed in the matrix.

Key words:Particle reinforced aluminum matrix composites，Shaping process，Microstructure and mechanical properties

 

 

第一章 绪论

1.1 引言

复合材料是由两种或两种以上异质、异形、异性的材料复合形成的新型材料。在复合材料中通常有一相为连续相，称为基体；有一种或几种不连续相分布于基体中，不连续相的强度、硬度比连续相高，称为增强体。增强体可以是纤维、颗粒状填料等。按基体分类，复合材料可分为聚合物基复合材料(PMCs)、金属基复合材料(MMcs)、陶瓷基复合材料(CMcs)。自上世纪80年代中期以来，颗粒增强金属基复合材料得到了迅速的发展。其中，颗粒增强铝基复合材料由于具有重量轻、比强度与比刚度高、剪切强度大、热膨胀系数低、热稳定性高等优点，并有良好的导热性和导电性、卓越的抗磨性、对有机液体如燃料和溶剂的耐侵蚀性，以及可用常规工艺和设备进行成型与处理，被广泛用于航空航天领域和汽车配件、体育用品等行业[1，2]。

但是，由于对颗粒增强金属基复合材料的研究时间较短，加之影响其性能的因素错综复杂，所以现在对颗粒增强金属基复合材料的制备、加工工艺还不完善，对其性能的了解也不全面。这些都将会影响和阻碍颗粒增强金属基复合材料的工业化生产和推广应用。

因此，为了更好的了解颗粒增强铝基复合材料，本文采用6063A