Abstract

Particle reinforced metal matrix composites (MMCs) offer high strength, low density, and high stiffness, while maintaining reasonable cost. The damage process in these MMCs starts with either the fracture of particles or by the de-cohesion of the particle-matrix interfaces. In this study, the extended finite elements method (XFEM) has been used in conjunction with X-ray synchrotron tomography to study fracture mechanisms in these materials under tensile loading. The initial 3D reconstructed microstructure from X-ray tomography has been used as a basis for the XFEM to simulate the damage in the 20 vol.% SiC particle reinforced 2080 aluminum alloy composite when tensile loading is applied. The effect of mesh sensitivity on the Weibull probability has been studied based on a single sphere and several particles with realistic geometries. Additionally, the effect of shape and volume of particles on the Weibull fracture probability was studied. The evolution of damage with the applied traction has been evaluated using simulation and compared with the experimental results obtained from in situ tensile testing.

Highlights

  • Metal matrix composites (MMCs) are attractive for many applications due to their excellent properties, including high strength and low density [1]

  • Microscopic stress concentrations that lead to the nucleation of cracks are strongly influenced by the size, shape, and distribution of reinforcing particles, and, will not be accurately represented in models with simplified geometry

  • To overcome these challenges, extended finite element method (XFEM) was developed by Belytschko et al [21,22] to model crack propagation without the need to remesh as the crack propagates

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Summary

Introduction

Metal matrix composites (MMCs) are attractive for many applications due to their excellent properties, including high strength and low density [1]. Due to its non-destructive nature, in situ X-ray synchrotron experiments have been conducted to understand the deformation behavior in real-time (4D), such as fatigue [14,15,16] and stress corrosion cracking (SCC) [14,17] These tomography experiments can be paired with the simulations of the same microstructure in order to calibrate and/or validate models [18,19]. The complexity of most real material geometries compounded by the immense size of microstructural data sets pose a significant modeling challenge for the traditional finite element codes, namely that it becomes increasing difficult to generate high quality meshes where element faces conform to the material interfaces To overcome these challenges, extended finite element method (XFEM) was developed by Belytschko et al [21,22] to model crack propagation without the need to remesh as the crack propagates. A systematic and microstructure-based understanding of damage and fracture in these materials was obtained and is discussed

Implicit Geometry Representation
Formulation of XFEM for Discontinuities
Implementation of Weibull Strength Distribution Model
Convergence study of Weibull Probability
Findings
Conclusions
Full Text
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