tib2颗粒增强a356铝基原位复合材料的微观组织和性能关系优化设计.doc

      

摘要： 对原位反应制备的铝基复合材料进行了研究。以A356-Na2B4O7-K2TiF6-KBF4为反应体系通过熔体反应法成功制备了TiB2/A356颗粒增强复合材料。研究了TiB2/A356颗粒增强复合材料的微观组织、相组成以及内生颗粒的形貌、大小及分布特征等，测试了复合材料的力学性能；研究了凝固速度对复合材料组织拉伸性能和冲击性能的影响，并初步探讨了复合材料的强化机制。实验结果表明按适当实验方案制备出的复合材料只含两种颗粒增强相。研究了冷却速度对TiB2/A356复合材料凝固行为的影响。对TiB2/A356复合材料进行了室温拉伸性能测试，研究表明：颗粒体积分数升高，抗拉强度 增大，而延伸率 有降低趋势；冷却速度的加快复合材料的拉伸性能显著提高，抗拉强度 提高，延伸率 提高59%。不同冷却速度时TiB2/A356颗粒增强复合材料的室温冲击韧性研究结果表明：随着冷却速度的增大复合材料的冲击韧性得到提高。

关键词：  TiB2/A356复合材料 原位反应 力学性能 冷却速度

 

The optimized design of microstructure and properties of TiB2 particulate reinforced A356 Al Based In-situ Composites

Abstract: We had studied about particle-reinforced Al-matrix composites prepared by in-situ reaction. In this study, A356-Na2B4O7-K2TiF6-KBF4 was chosen as reaction system. TiB2/A356 particle-reinforced composites were prepared using melt reaction. Characterization tests have been performed to discuss the microstructures and phases constitution of the composite materials as well as size, appearance and distribution characteristics of the reinforced particles in order to test the mechanical properties; Experiments were carried out to examine the effects of solidification rate on tensile and impact properties of the composite material as well as the strengthening mechanism of the material.It has been observed that the composite materials prepared by the appropriate experimental scheme are only two kinds of particle reinforced phase. The Solidification Behavior of TiB2/A356 composite with different cooling rate were showed. The tensile properties of TiB2/A356 composite materials in room temperature show that as the reinforced particles increases, tensile strength   increases and elongation rate   decreases. The tensile properties of the composite were significantly improved, the tensile strength was improved, and the elongation was increased by 59%.The impact ductility of TiB2/A356 composite materials with different solidification rate in room temperature show that the impact ductility of the composite materials improves as the solidification rate increases. 

Key words: TiB2/A356 composite materials  melt in-situ reaction  mechanical properties  

             cooling velocity