旋转摩擦挤压制备MWCNTs/Al复合材料的组织及磨损性能EI北大核心CSCD

采用旋转摩擦挤压(RFE)法制备多壁碳纳米管增强铝基(MWCNTs/Al)复合材料,分析MWCNTs/Al复合材料的显微组织、硬度和磨损性能。结果表明:用RFE法可制备具有一定形状尺寸的块体MWCNTs/Al复合材料;复合材料的成形质量好,显微组织为经动态再结晶后的细小等轴晶,MWCNTs在铝合金基体中分布均匀。复合材料的硬度随着MWCNTs体积分数增加先增加后降低,当MWCNTs体积分数为4%时,硬度是经RFE加工后基材的1.2倍。MWCNTs在复合材料磨损过程中起润滑作用,有助于降低MWCNTs/Al复合材料的磨损量提高复合材料的耐磨性。随MWCNTs体积分数的增加,复合材料的磨损率降低,当MWCNTs体积分数大于3%后磨损率变化较小。这是由于MWCNTs体积分数的增加,磨损机制发生变化,即由黏着磨损和轻微磨粒磨损转变为剥层磨损和磨粒磨损。

M icrostructure and T ribological Property of M WCN T s/Al Composites by Rotational Friction Ex trusion Process

The aluminum matrix composites reinforced with the multi‐walled carbon nanotubes (MWC‐NTs) were fabricated by rotational friction extrusion (RFE) process and the microstructure ,hardness and tribological property of the composites were investigated .The results show that the bulk compos‐ites with certain dimension can be fabricated by the RFE process .The microstructure of the compos‐ites appears as fine equiaxed grain after dynamic recrystallization and the quality is good .The MWC‐NTs are uniformly distributed in the composites .The hardness of the composites increases firstly and then decreases with the increase of MWCNTs .When the volume fraction of MWCNTs is about 4% , its hardness is about 20% higher than that of the original Al matrix material by RFE process .The lu‐brication and wear resistance of the composites are changed with the addition of MWCNTs .With the increase of the MWCNTs ,the wear rate of the composites is decreased at first ,and when the volume fraction of MWCNTs is more than 3% ,the wear rate varies little .The wear mechanism is changed , which is from adhesion wear and mild abrasive wear to the delamination wear and abrasive wear with the increase of the MWCNTs .