亚微米颗粒增强铝基复合材料的制备、组织与性能研究

【作者】 李洪武；

【导师】 易丹青；

【作者基本信息】 中南大学 ， 材料学， 2004， 硕士

【摘要】 本文率先将高能球磨和半固态挤压技术相结合，形成亚微米颗粒增强铝基复合材料制备新技术。通过自行设计的半固态挤压装置，采用高能球磨—半固态挤压制备了亚微米SiCp／2014Al和SiCp／6066Al复合材料，利用金相显微镜、扫描电镜、万能电子拉伸机、热分析仪、维氏硬度计等手段系统研究了亚微米SiCp／Al复合材料的显微组织、力学和热物理性能。并通过对材料的组织性能分析，研究了不同有机溶剂对亚微米颗粒在基体中的分散效果，半固态挤压工艺参数对材料组织性能的影响，以及亚微米颗粒增强铝基复合材料的强化机制、断裂机制、时效硬化行为等。得出的主要结论如下： 1．亚微米陶瓷颗粒有良好的增强效果。一定体积分数内，亚微米颗粒增强铝基复合材料的力学性能随增强体含量的增加而增加，但增强体含量过多时，复合材料中的增强体聚集区和增强体／增强体界面反而会恶化材料的力学性能。 2．随着亚微米增强体含量的增加，复合材料的主要微观断裂机制沿“基体撕裂→增强体／基体界面开裂→增强体／增强体开裂”转变。 3．复合材料的最佳半固态挤压温度为复合材料中液相体积分数为40％时基体所对应的温度；提高挤压比，有利于复合材料性能的提高。 4．在丙酮、正丁醇、乙醇三种有机溶剂中，丙酮在混料时对0.13μm的SiC分散效果最好，采用其作为混料介质制各的复合材料性能最好。 5．弥散分布的亚微米颗粒并未影响基体合金的时效动力学，复合材料的峰时效时间与基体合金相同，但颗粒含量过高时，复合材料中的大尺寸颗粒团聚体起到了微米级增强颗粒加速基体合金时效析出的作用。 6．采用高能球磨—半固态挤压技术制备的亚微米SiCp／Al复合材料具有较好的颗粒分散性，材料具有良好的力学和热物理性能。更多还原

【Abstract】 With the combination of high energy ball milling method and semi-solid extrusion method, in this paper the technique of preparing sub-micron particle strengthening aluminum matrix composite was developed firstly. Through the semi-solid instrument devised by ourselves, sub-micron SiCp/2014Al and SiCp/6066Al composites were prepared by the utilization of high energy ball milling- semi-solid extrusion method. Optical microscopy, scanning electron microscopy, universal material testing machine, thermal analyzer and Vickers hardness tester were used to study the microstructure, mechanical and thermal physical properties of sub-micron SiCp/Al composites. Through the analysis of microstructure and properties of materials, the influence of different solvents on dispersion effects of sub-micron particles in matrix, the influence of semi-solid extrusion parameters on microstructure and properties of materials, strengthening mechanism , fracture mechanism , aging hardening behavior of sub-micron particles strengthening aluminum matrix composites were studied in this paper. The main conclusions were as follows:1. Sub-micron ceramic particles owned the excellent strengthening effect. In a certain range of strengthening particles volume fraction, mechanical properties of sub-micron particle strengthening aluminum matrix composites increased with the increasing of the volume fraction of strengthening particles, however, when the volume fraction of strengthening particles was excessive, gathering area of strengthening particles and interface between strengthening particles in composites would worsen the mechanical properties of materials.2. With the increasing of volume fraction of sub-micron strengthening particles, the main microscopic fracture mechanism of composites changed as the following sequence: "fracture of matrix → fracture of interface between strengthening particles and matrix → fracture between strengthening particles".3. The optimal semi-solid extrusion temperature was the temperature of matrix when volume fraction of liquid phase reached 40% inAbstractcomposites; Increasing of extrusion ratio was beneficial to the improvement of mechanical properties of composites.4. For three organic solvents of acetone nor-butanol and ethanol, acetone owned the best dispersion effect on 0.1 3 [am SiC particles during the process of blending. Taking acetone as the blending medium the composites had the optimal properties.5. Dispersed sub-micron particles didn’t influence the aging kinetics of matrix alloy, the peak aging time of composites was the same with that of matrix alloy. While the volume fraction of particles was excessive, large size particle aggregates played a role that micron strengthening particles accelerated the aging precipitation in matrix alloy.6. Sub-micron SiCp/Al composites prepared by high energy ball milling and semi-solid extrusion techniques owned excellent particle dispersion ability, and the materials owned excellent mechanical and thermal physical properties.更多还原