基于三维随机细观模型的SiCp/Al复合材料力学性能分析

Analysis of mechanical properties of SiCp/Al composites based on three-dimensional random meso-model

基于颗粒增强铝基复合材料的细观组成及结构特点,建立了考虑颗粒、基体、界面性能的三维随机细观颗粒增强复合材料分析模型和方法。在细观尺度上,分别采用立方颗粒、球形颗粒及三维随机多面体模型来表征颗粒的形状,根据颗粒原材料粒度分析获得的粒径分布数据,建立考虑颗粒空间分布的随机特性及粒径的概率分布特征的三维随机代表性体积单元。在Ludwik模型基础上考虑淬火硬化效应,描述铝基体的弹塑性本构关系,考虑了基体的韧性损伤、SiC颗粒的弹脆性破坏以及界面的拉伸-开裂行为,模拟了材料在单轴拉伸过程中的变形和损伤过程。开展SiCp/Al2009复合材料标准件的单轴拉伸试验验证,结果表明:弹性模量、屈服强度和拉伸强度的预测最大误差分别在5%、5%及11%以内;弹性模量的预测结果受颗粒形状影响较小;其中,三维随机多面体模型的拉伸强度预测精度最高,且能反映出颗粒增强复合材料拉伸断裂过程中的基体韧性断裂、颗粒脆性破坏以及界面脱黏的破坏模式;该模型和方法可为颗粒增强铝基复合材料的细观损伤机理及宏观力学性能分析提供有益的参考。

Based on the mesoscopic composition and structural characteristics of particle reinforced aluminum matrix composites,a three-dimensional random meso particle reinforced composites analysis model along with its method considering particle,matrix and interface properties was established.On the meso scale,cubic particle,spherical particle and three-dimensional random polyhedron models were used to characterize the shape of particles respectively.According to the particle size distribution data obtained from particle raw material particle size analysis,a three-dimensional random representative volume element considering the random characteristics of particle spatial distribution and the probability distribution characteristics of particle size was established.Based on Ludwik model,considering the quenching hardening effect,the elastic-plastic constitutive relationship of aluminum matrix was described.The ductile damage of matrix,the elastic-brittle failure of SiC particles and the tensile cracking behavior of interface were considered.The deformation and damage process of material in uniaxial tension were simulated.The uniaxial tensile test verification of SiCp/Al2009 composite standard parts was carried out.The results showed that the maximum errors of elastic modulus,yield strength and tensile strength were less than 5%,5%and 11%,respectively;the prediction result of elastic modulus was less affected by particle shape;among them,the three-dimensional random polyhedron model had the highest prediction accuracy of tensile strength,and can reflect the failure modes of matrix ductile fracture,particle brittle failure and interface debonding in the tensile fracture process of particle reinforced composites.The model and method can provide a useful reference for the analysis of meso damage mechanism and macro mechanical properties of particle reinforced aluminum matrix composites.