Modelling fracture in an Al2O3 particle reinforced AA 6061 alloy using Weibull statistics

摘要

Fracture in an AA6061 based metal matrixcomposite (MMC) containing 20vol%Al2O3 particles is modelledusing an axisymmetrical finite element model and a statisticalapproach for calculating the strength of reinforcing ceramicparticles via the Weibull model. Within this model. Variables suchas the volume fraction, particle size and matrix alloy properties canbe varied.When modelling the fracture behaviour of one particle, itis assumed that the survival probability of the ceramic particle isgoverned by a Weibull distribution. Fracture statistics of the MMCis examined by plotting the survial probability of an Al2O3 particlevs. The macroscopic axial stress applied on the whole MMC.Based on initial calculations it can be concluded that the relationbetween the macroscopic applied stress on the MMC and thesurvival probability of the ceramic particle can be described by theWeibull modulus m, as long as the stress distribution in the matrixsurrounding the particle is proportional to the applied load and thattriaxial loading of the MMC results in a lower survival probabilitycompared to uniaxial loading Fracture behaviour of MMCs canwell be described and a 'mastercurve' can be made for variouscharacteristic stresses and matrix yield stresses at a specifichardening exponent for the matrix material.