金属基及陶瓷基复合材料界面脱胶引起刚度下降的估算

STIFFNESS REDUCTION OF METAL MATRIX AND CERAMIC MATRIX COMPOSITES DUE TO INTERFACIAL DEBONDING

根据扫描电子显微镜(SEM)及复型技术的断裂机理分析,复合材料纤维-基体脱胶是由于纤维的断裂导致了靠近断裂处的界面上产生很高的剪应力。当这个剪应力超过界面的剪切强度,断裂处附着的纤维将会与基体产生脱胶。本文依据上述断裂机理,提出了一金属基及陶瓷基复合材料界面脱胶引起刚度下降估算的数学模型。分析结果表明,这些复合材料的刚度降较聚合物基的刚度降小,但随纤维与基体扬氏弹性模量的比值而增加。

SEM micrograph of replica points to the fact that a fiber break induces very high shear stresses at the fiber-matrix interface near the break.If this stress exceeds the shear strength of interface,the fiber will debond from matrix in the vicinity of the break.Based on this micrograph,a model is presented in this paper for the analysis of stiffness reduction of metal matrix and ceramic matrix composites due to interracial debonding.They are far less than those of polymer matrix composites,and increasing with E_f/E_m.