多壁碳纳米管增强铝基复合材料的高温力学性能

摘要

Aluminum matrix composites reinforced by different contents of multi-walled carbon nano-tubes(MWCNTs)were fabricated by friction stir processing(FSP),and their high temperature me-chanical properties and strengthening mechanism were studied.The results indicate that by adding MWCNTs,the microstructure of the composites becomes finer,and a small amount of nanocrystals and tangled dislocations are brought into the aluminum matrix.Compared with the aluminum matrix, the strength of the composites at high temperature is enhanced significantly through adding MWC-NTs.The strength of the composites is improved gradually,as the MWCNTs content increases,on the contrary,the plasticity of the composites decreases constantly.When the test temperature is 350℃,the tensile strength of 6.6%(volume fraction)MWCNTs/Al composite is up to 78MPa,which is 3 .9 times of aluminum matrix without adding MWCNTs.The dimples of composites fracture grad-ually decreases,exhibits brittle fracture,as the testing temperature increases.%采用搅拌摩擦加工技术制备不同含量多壁碳纳米管增强铝基复合材料,并对复合材料高温力学性能进行研究.结果表明:多壁碳纳米管的添加使得铝基体材料微观组织更加细小,并形成了少量纳米晶;铝基体中有较高密度位错,并在局部呈位错缠结状分布.与未添加多壁碳纳米管的铝基体相比,复合材料的高温拉伸强度明显增强,且随着碳纳米管含量的增加,复合材料强度逐渐提高,而高温塑性不断降低,350℃时,6.6%(体积分数)MWCNTs/Al复合材料的抗拉强度达到78MPa,为未添加多壁碳纳米管铝基材强度的3.9倍;断口分析表明,随着测试温度的提高,韧窝逐渐变小,呈脆性断裂特征.