粉末冶金法碳纳米管增强镁基复合材料的微观组织及力学性能

Microstructure and mechanical properties of carbon nanotube reinforced magnesium matrix composites by powder metallurgy

碳纳米管具有优异的物理性能和力学性能,一直被认为是金属基复合材料的理想增强体,然而,由于细小的碳纳米管之间存在较强的范德华力引起严重的团聚,因此如何制备获得增强体分布均匀的复合材料一直是本研究领域的热点问题。本文分别通过球磨法和异丙醇(IPA)溶液分散法将碳纳米管与镁粉混合,然后采用冷压、烧结制备碳纳米管增强镁基复合材料,采用金相显微镜、SEM、XRD以及硬度计等手段,对比分析了两种混粉方法,质量分数为1%的碳纳米管增强镁基复合材料的微观组织和力学性能。研究结果表明,IPA溶液将碳纳米管均匀地分散在镁颗粒表面,仅有少量团聚;冷压烧结制备获得的复合材料组织致密,碳纳米管分布均匀;XRD结果表明,烧结后的复合材料有少量MgO存在;碳纳米管的加入使纯镁的硬度提高18%。

Because carbon nanotubes(CNTs)possess superior physical properties and mechanical properties,they are considered as one of the ideal reinforcement for metal matrix composites.It is,however,obvious that segregation of CNTs due to their strong van der Waals forces will produce material defects,decreasing the material properties.So it is a important research topic to obtain the composites with CNTs dispersed well.CNTs and pure magesium powders were mixed thoroughly either by ball milling or in the isopropanol(IPA)in the present study, Mg powder with CNTs were fabricated into CNTs reinforced Mg matrix composites with cold pressing and sintering.The microstructure and mechanical properties of the composites with the mass fraction of 1% CNTs were analyze contrastively by optical microscope,SEM,XRD and hardness tester.SEM results show that CNTs are dispersed by IPA on the surface of Mg powders and the minority of them are aggregated.XRS results show that a small amount of MgO exsits in the sintered composites.The hardness of Mg/CNT composites by IPA and by ball milling is improved with 18%and 0%compared to that of pure Mg without CNTs.