碳纳米管增强镁基复合材料的界面分离特性

Interface debonding properties of carbon nanotube-reinforced magnesium matrix composites

建立碳纳米管增强镁基复合材料界面弹性应力传递摩擦拔出模型,得到镁基复合材料各组分的应力和应变。考虑泊松效应和界面上摩擦应力的作用以及基于界面分离过程能量平衡和界面应变失配原则,得到界面能释放率和裂纹位移展开轮廓的表达式。分别从界面能释放率和裂纹位移展开轮廓两个方面研究复合材料性能参数对碳纳米管增强镁基复合材料断裂的影响。结果表明:界面分离长度和界面厚度较大,则复合材料的界面分离能释放率就越大;较大的界面分离长度、界面厚度、弹性模量和泊松比均对复合材料的裂纹位移展开轮廓产生较大影响;碳纳米管长径比越小,则复合材料的界面分离能释放率和裂纹位移展开轮廓越大;对界面材料的弹性模量和泊松比选择存在着最佳值。

A theoretical model on the frictional pull-out properties of CNTs/Mg composite was presented to describe the interfacial elastic stress transfer,then the stress and strain of respective components of CNTs/Mg composite were derived.Considering the Poisson＇s effect and friction stress at the debonded interface and based on the energy equilibrium and the interphase strain criterion in the interfacial debonding process,an expression for the energy release rate and the crack opening displacement profile was derived.The effects of the parameters on the fracture characteristics of CNTs/Mg composite were investigated by the relative energy release rate and crack opening displacement profile.The results show that the greater the interface debond length and interface thickness are,the better the relative energy release rate can be obtained.Larger interface debond length,interface thickness,interface elastic modulus and interface Poisson＇s ratio have more influence on the crack opening displacement profile.The smaller the CNTs aspect ratio is,the better the relative energy release rate and the crack opening displacement profile can be obtained.The interface elastic modulus and interface Poisson＇s ratio have optimum effects for the magnesium matrix composites.