碳纳米管增强AZ91D复合材料微区应力场的有限元模拟

Simulation of micro-volume stress field in AZ91D composite reinforced with carbon nanotubes by using finite element method

采用有限元方法仿真模拟碳纳米管(CNTs)增强AZ91D镁合金复合材料CNTs/AZ91D中碳管以及周围的微区应力场,并且对弹性条件下与弹塑性条件下镁合金基体等效应力场和碳纳米管等效应力分布进行对比.结果表明,CNTs/AZ91D复合材料在相同拉力下,整体轴向变形比未加CNTs的AZ91D复合材料轴向变形明显减小,应力集中现象仅出现在CNTs与AZ91D基体接触的两端面上,应力的最大值处于CNTs端口附近,镁基复合材料的强化主要来自增强体的强化作用.复合材料的破坏是从界面处开始,其破坏机制是界面脱开.

The micro-volume stress field of carbon tubes and their surroundings within the AZ910D magnesium alloy composite（CNTs/AZ91D） reinforced with carbon nanotubes（CNTs） was simulated by using finite element method,and the equivalent stress field in magnesium alloy matrix was compared with the equivalent stress distribution in the carbon nanotubes in both the elastic and elastic-plastic condition.It was shown by the simulation result that overall axial deformation of the composite（CNTs/AZ91D） under tensile load was remarkably less than that of AZ91D composite without addition of CNTs.Stress concentration took place only around the two end surfaces of contact of CNTs with AZ91D matrix and the maximum stress was located at the vicinity of CNTs end.The streng thening of magnesium composite was the result of streng thening effect of reinforcing phase.Fracture of the composite originated from the interface and its mechanism was interface fracture.