Microstructure and mechanical properties of the carbon nanotubes reinforced AZ91D magnesium matrix composites processed by cyclic extrusion and compression
Microstructure and mechanical properties of the carbon nanotubes reinforced AZ91D magnesium matrix composites processed by cyclic extrusion and compression
复制标题
循环挤压压缩碳纳米管增强AZ91D镁基复合材料的显微组织和力学性能
DOI：
10.1016/j.msea.2017.02.076
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发表时间：
2017-03-24
期刊：
影响因子：
6.4
通讯作者：
Ding, Wenjiang
中科院分区：
文献类型：
--
作者：
Zhang, Li;Wang, Qudong;Ding, Wenjiang
采用循环挤压工艺制备了碳纳米管增强AZ91D复合材料。研究了CEC道次和碳纳米管对复合材料组织演变、硬度和拉伸性能的影响。结果表明，经过8道次CEC处理后，0.5wt%CNTs/AZ91D复合材料的基体晶粒由约112 μ m细化到约126.6nm，Mg17Al12沿晶界沿着分布均匀。添加碳纳米管导致减少基体晶粒，但施加的Mg17Al12沉淀的影响有限。随着CEC的进行，初始高度团聚的碳纳米管逐渐分散，但碳纳米管发生降解。CEC的实施显著提高了AZ91D合金和CNTs/AZ91D复合材料的硬度、YS、UTS和断裂伸长率，这主要归因于基体晶粒的显著细化和Mg17Al12相的均匀分布。碳纳米管的加入提高了基体合金的硬度、屈服强度和抗拉强度，但降低了断裂伸长率，这与碳纳米管的逐渐分散和降解密切相关。
Cyclic extrusion and compression (CEC) was taken to process the carbon nanotubes (CNTs) reinforced AZ91D composites. Effects of CEC passes and CNTs on the microstructure evolution, hardness and tensile properties of the post-processed composites were investigated. Results show that the matrix grain of the 0.5 wt% CNTs/ AZ91D composites is greatly refined from similar to 112 mu m to similar to 126.6 nm after 8 passes of CEC, with Mg17Al12 uniformly distributed along grain boundaries. The addition of CNTs leads to a reduced matrix grain, but exerts a limited effect on the Mg17Al12 precipitates. The initial highly-agglomerated CNTs are gradually dispersed with the progress of CEC, though degrading of CNTs occurs. The implement of CEC markedly enhances the hardness, YS, UTS and elongation to fracture of both the monolithic AZ91D alloy and the CNTs/AZ91D composites, all of which are mainly attributed to the greatly refined matrix grain and the uniformly distributed Mg17Al12 precipitates. Incorporation of CNTs increases the hardness, YS and UTS of the base alloy, but decreases the elongation to fracture, which is closely related with the gradually dispersed but degraded CNTs.