机械球磨制备轻质高强碳纳米管增强铝基复合材料研究进展

来源 :2015中国汽车工程学会年会 | 被引量 : 0次 | 上传用户:w119127594
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本文综述了不同机械球磨工艺对碳纳米管(carbon nanotuhes,CNTs)分散性、结构完整性以及最终铝基复合材料力学性能的影响.通过分析上述影响因素,讨论了机械球磨工艺制备轻质高强碳纳米管增强铝基复合材料未来的研究方向.机械球磨,其本质上属于自下而上的一种方法论,即通过对组元进行加工,再将各个组元组装成宏观块体材料。在机械球磨过程中,因为CNT、在尺度上与微米级Al粉更具相容性,所以相对SPD更容易获得CNT、的均匀分散。然而,一方面为了保护CNT、结构的完整性而采用短时低能球磨甚至是无球磨介质的工艺进行球磨,对CNT、的分散效果有限,而且CNT、与Al基体的机械结合强度弱以及Al本身加工变形程度低,基体未得到充分强化,导致低能球磨所制备的CNT/Al复合材料力学性能提高有限甚至是恶化。另一方面,在高能球磨过程中,一味通过延长机械球磨时间来解决CNT、分散以及Al组织结构细化的问题。然而,在此苛刻的变形条件下,CNT、被剪断结构遭到破坏,严重地削弱了CNT、的承载能力,并且在恒定的变形条件下,Al基体由于不断的变形、内部位错的增殖和塞积,导致位错的继续增殖累积越来越困难,晶粒细化效率降低,细化结构的饱和性不高。此外,机械球磨是一种自下而上的过程,必然要经历后续的高温热致密化过程,导致细化组织的回复、再结晶甚至是晶粒长大,抵消球磨变形过程中A1基体的强化效果。因此,能够有效分散CNTs、结构破坏程度低同时能够有效强化Al基体的机械球磨变形工艺有待进一步开发。
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