碳纳米管增韧Al-Mg合金复合材料的制备与性能研究

Preparation and properties of carbon nanotubes toughenedAl-Mg alloy composite materials

选择碳纳米管为增强相,通过搅拌铸造法制备了碳纳米管增韧Al-Mg合金复合材料,研究了碳纳米管的添加量对复合材料力学性能、微观组织以及韧性的影响,并探究了碳纳米管对Al-Mg合金的增韧机理。结果表明,掺入适量的碳纳米管后细化了Al-Mg合金复合材料的晶粒,晶粒尺寸约为80μm,当碳纳米管的添加量为0.8%(质量分数)时,复合材料的断口形貌最均匀。随着碳纳米管添加量的增大,复合材料的抗拉强度、断裂伸长率、硬度均表现出先增大后降低的趋势,当碳纳米管的添加量为0.8%(质量分数)时,抗拉强度、断裂伸长率和硬度均达到了最大值,分别为208.6 MPa、15.8%和53.1 HB。适量碳纳米管的添加显著改善了Al-Mg合金的韧性,使断裂延伸率逐渐增大,屈服阶段延长,韧性得到提高,这是因为适量的碳纳米管添加后能够与合金发生较好的结合,并贯穿于合金的裂纹中,发挥出了桥联作用,阻碍了裂纹的萌生和扩展,从而改善了Al-Mg合金复合材料的韧性,延缓了合金的失效过程,延长了合金的屈服阶段。综上分析可知,碳纳米管的最佳添加量为0.8%(质量分数)。

Carbon nanotubes were selected as the reinforcing phase and a carbon nanotube toughened Al-Mg alloy composite material was prepared by stirring casting method.The effects of the amount of carbon nanotubes added on the mechanical properties,microstructure and toughness of the composite materials were studied,and the toughening mechanism of carbon nanotubes on Al-Mg alloy was explored.The results showed that the addition of an appropriate amount of carbon nanotubes refined the grain size of the Al-Mg alloy composite material,with a grain size of approximately 80μm.When the addition amount of carbon nanotubes was 0.8 wt%,the fracture morphology of the composite material was the most uniform.As the amount of carbon nanotubes added increased,the tensile strength,elongation at break,and hardness of the composite material showed a trend of first increasing and then decreasing.When the addition amount of carbon nanotubes was 0.8 wt%,the tensile strength,elongation at break,and hardness all reach their maximum values,which were 208.6 MPa,15.8%and 53.1 HB,respectively.The addition of appropriate amount of carbon nanotubes significantly improves the toughness of Al-Mg alloy,gradually increasing the fracture elongation,prolonging the yield stage,and improving the toughness.This is because an appropriate amount of carbon nanotubes can bind well with the alloy and penetrate the cracks of the alloy,exerting a bridging effect and hindering the initiation and propagation of cracks,thereby improving the toughness of Al-Mg alloy composites,delaying the failure process of the alloy,and extending the yield stage of the alloy.Based on the above analysis,it can be concluded that the optimal addition amount of carbon nanotubes is 0.8 wt%.