碳纳米管对镁锌合金组织及性能的影响  

Effects of Carbon Nanotubes on Microstructure and Mechanical Properties of Magnesium-Zinc Alloy

作　　者：黄秋玉[1] 曾效舒[1] 曾刚[1] 周国华[2] 

机构地区：[1]南昌大学机电工程学院材料加工系,江西南昌330031 [2]宜春学院物理科学与工程技术学院,江西宜春336000

出　　处：《稀有金属》2012年第5期750-756,共7页Chinese Journal of Rare Metals

基　　金：江西省科技厅攻关项目(z02727)资助

摘　　要：采用钟罩浸块铸造法制备了不同碳纳米管含量的镁锌合金铸锭,经热挤压后制备出不同碳纳米管含量变形镁锌合金,研究碳纳米管作为增强材料加入到不含铝的镁锌二元合金中,对其组织和性能产生的影响。利用光学显微镜、扫描电镜及拉伸强度实验机对其显微组织形态及力学性能进行了分析。结果表明,碳纳米管的加入能够显著细化合金铸锭的晶粒起到了细化树枝晶二次枝晶臂间距和转变晶体生长方式的作用,且经过热挤压变形后组织变得更加均匀细小,具有细晶组织;碳纳米管对热挤压镁锌合金的力学性能有增强作用,提高了镁锌合金的抗拉强度、屈服强度、延伸率,当加入量为1.0%时,分别达到最大值219.740,215.969 MPa,27%,其中以延伸率的提高最为显著,抗拉强度和屈服强度值趋于稳定,可得碳纳米管加入到镁锌合金中,起到了较好的复合效果,对晶粒和晶界起到细化和强化的作用,使得该材料具有较高塑形的同时没有降低其强度;合金的断裂特征为典型韧性断裂,有较深的圆形韧窝和撕裂棱组成,碳纳米管与基体合金结合紧密,在拉伸断口处的白色须状物质即为表面被基体合金包覆的碳纳米管。Ingot castings of magnesium-zinc alloy with different content of carbon nanotube were prepared by bell jar immersing precast block casting,and then wrought magnesium-zinc alloy with different content of CNTs were produced through extrusion deformation.The influence of the addition of carbon nanotubes on the microcosmic structure and the mechanical properties of the magnesium-zinc alloy without aluminum were researched.The microcosmic structure and the mechanical properties of the composites were observed by using the optical microscopy and scanning electron microscopy and experimental study of tensile strength.The results showed that the CNTs could greatly refine the grains of magnesium-zinc alloy as cast condition and it also could play a role in refining the two dendrite arm spacing and changing the crystal growth method.Then grain became smaller and more symmetrical after extrusion deformation and the composites had fine grain structure.The CNTs could enhance the mechanical properties of magnesium-zinc alloy as-extrusion such as tensile strength,yield strength and elongation.When the addition amount was 1.0%,the maximum of tensile strength,yield strength,elongation was 219.740,215.969 MPa and 27%.The increase of elongation was the most significant and the strength value was more stable.The addition of carbon nanotubes into magnesium-zinc alloy had good composite effect,and played a role in refining and strengthening the grain and grain boundary so that the alloy had superior plasticity besides high strength.The fracture sections of the alloy mainly consisted of dimples and prisms,which demonstrated toughness cleavage modes.Carbon nanotubes and matrix alloy were combined tightly.The white whisker material in tensile fracture was the carbon nanotubes whose surface was coated by matrix alloy.

关 键 词：镁锌合金 碳纳米管 挤压变形 显微组织 力学性能 

分 类 号：TG146.22[一般工业技术—材料科学与工程]