Mean-field model analysis of deformation and damage in friction stir processed Mg-C composites

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:723

Article

Simar, Aude¹  Mertens, Anne²  Ryelandt, Sophie¹  Delannay, Francis¹  Brassart, Laurence³ 

[1] Catholic Univ Louvain, Inst Mech Mat & Civil Engn, 2 Pl Sainte Barbe,Batiment Reaumur L5-02-02, B-1348 Louvain La Neuve, Belgium

[2] Univ Liege, Fac Appl Sci, A&M Dept, Metall Mat Sci Unit, Quartier Polytech 1,13A Allee Decouverte, B-4000 Liege, Belgium

[3] Monash Univ, Dept Mat Sci & Engn, 22 Alliance Lane, Clayton, Vic 3800, Australia

关键词: Magnesium matrix composites;    Friction stir processing;    Interface debonding;    Micromechanics;    Micromechanical modelling;   

DOI  :  10.1016/j.msea.2018.03.043

来源: Elsevier

【 摘 要 】

Friction Stir Processing (FSP) is an attractive manufacturing technique to produce Mg matrix composites since it avoids the problem of excessive reactivity between reinforcement and matrix encountered in liquid-phase processing routes. However, the strength of the interface in C-reinforced Mg matrix composites produced by FSP remains to be assessed. A short fibre composite has been fabricated by FSP a stack of a C-fabric between two Mg-AZ91D alloy sheets. hi order to elucidate the interplay between matrix hardness and interface bonding strength, the work investigates the influence of heat treatment on the mechanical properties of the composites. An incremental Mori-Tanaka model is developed to analyse the relative roles of heat treatment and C-fibre reinforcement on the flow strength and ductility of the composites in tension and compression. The mean-field model provides an estimate of the stress at the matrix/fibre interface, from which a simple debonding criterion can be derived. Comparison between model predictions and experimental data indicates that damage in the FSP composites is triggered by early interfacial debonding. Based on Finite Element simulations of a tensile test carried out in-situ in a scanning electron microscope, the critical interfacial stress for debonding was identified to be 435 MPa in simple traction but only 250 MPa when damage is governed by shear. This explains the limited strengthening by C fibres observed in heat treated composites.

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