SiC_p/6151Al复合材料的微结构效应

利用分离式Hopkinson压杆和MTS通用材料试验机研究了SiC_p/6151Al颗粒增强复合材料在不同应变率下的变形行为和增强颗粒的尺寸对复合材料微结构及变形行为的影响。结果表明，对于在不同应变率下的SiC_p/6151Al复合材料，增强颗粒尺寸大小的流动应力高于增强颗粒尺寸的流动应力。根据位错强化理论中的Hall-Petch关系对这个结果进行了解释。首次在实验上观测到增强颗粒对复合材料微损伤-微带形成的影响，并根据微带（microband）形成的双位错墙理论（double dislocation walls）, 分析了增强颗粒对复合材料微带损伤及力学性能影响的微结构效应。

<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">The deformation behavior under different strain rates and effect of particle size in SiC_p particle-reinforced 6151Al matrix SiC_p/6151Al composites were investigated. The experimental results demonstrate that there have been microstructure effects under different strain rates in particle-reinforced composites. That is the strengthening effect of the small-size particle-reinforced composite is higher than that of the large-size particle-reinforced composite. The explanation is given based on the dislocation-reinforced theory. At the same time, according to the theory of double dislocation walls on formation of microband, the effect of reinforced particle size on the microband formation is explicated. The micrographs of loaded samples showed that reinforcing particles block the formation of microbands. The microstructure analysis shows that reinforcing particles and its size are the main cause of microstructure change and reinforcing effect.</span>