有界面脱粘时颗粒增强金属基复合材料的弹塑性性能分析

基于Mori-Tanaka理论和Eshelby等效夹杂理论,假定基体和增强相界面结合完好,推导出在力的边界条件下两相复合材料各组成相的应力、应变以及复合材料的体平均应变和应力,并考虑了基体和增强颗粒热膨胀系数引起的热应变以及各相塑性应变的影响.在此基础上,假定基体和复合材料均为各向同性材料,颗粒仅产生弹性变形,基体产生弹塑性变形且满足Mises屈服准则和等向强化准则,由颗粒所受的拉应力控制界面的脱粘,脱粘概率由Weibull分布函数来描述,脱粘后的颗粒等效为孔洞,采用割线模量法讨论了球形颗粒增强金属基复合材料有界面脱粘时的弹塑性性能,理论预测与实验结果吻合较好.

Elastoplastic Behavior of Particle Reinforced Metal Matrix Composites Considering the Interfacial Debonding

Based on Mori-Tanaka's concept of average stress in the matrix and Eshelby's equivalent inclusions theory,the stress or strain of the matrix,the reinforced particles and the composite are derived under a prescribed traction boundary conditions.The plastic strains and strains due to thermal mismatch between matrix and reinforced phase are considered as eigenstrains.Then the elastoplastic properties of the spherical particle reinforced metal matrix are discussed considering the interfacial debonding by secant modulus method.In this paper,the matrix and composite are postulated isotropic and the matrix satisfies Mises yield criterion and isotropic hardening law.The interface debonding is decided by the tensile strength of the particles and the debonding probability is described by Weibull distribution.The theoretical uniaxial stress-strain bebavior of the composite agrees well with the experimental curves.