搅拌摩擦加工制备MWCNTs／Al复合材料显微结构及硬度

摘要

采用搅拌摩擦加工技术（FSP）制备多壁碳纳米管增强铝基（MWCNTs／A1）复合材料，并对该复合材料的显微结构和硬度进行分析。结果表明：MWCNTs／Al复合材料显微结构为细小的等轴晶，晶粒大小不均匀；MWCNTs与Al基体界面结合良好，界面处分布大量的位错，MWCNTs主要分布在晶内；动态再结晶形核方式为亚晶形核，在原始晶粒和已形成的亚晶内形核，经动态再结晶使晶粒逐步细化；MWCNTs／Al复合材料的硬度随MWCNTs含量增加呈上升的趋势，当CNTs体积分数为6％时，MWCNTs／Al复合材料硬度达Hv63．4，为纯Al经5次FSP硬度的1．9倍。%Multi-walled carbon nanotubes（MWCNTs） reinforced Al matrix composites were prepared by friction stir processing（FSP）. The microstructure and hardness of the composites were investigated. The results show that the MWCNTS/Al is composed of fine equiaxed grains but the grains are uneven. The interface between MWCNTs and the matrix is well binded. A large numbers of dislocations were distributed in the interface. MWCNTs mainly distributed within the aluminum grains. The grain refinement is realized by recrystallization through a subcrystal nucleating mode. The nucleis form nucleus in the primary grains and the formed subcrystal. Therefore, the grains are refined gradually. With increasing MWCNTs content, the hardness of MWCNTs/Al composite increases. When the volume fraction of MWCNTs is 6 %, the microhardness is HV 63.4 which is 1.9 times as hard as Al made after 5 times of FSP.