Observation of void nucleation, growth and coalescence in a model metal matrix composite using X-ray tomography

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

卷:488

Article

Weck, A.¹  Wilkinson, D. S.¹  Maire, E.² 

[1] McMaster Univ, Dept Mat Sci & Engn, Hamilton, ON L8S 4L7, Canada

[2] CNRS, UMR 5510, MATEIS INSA Lyon, F-69621 Villeurbanne, France

关键词: void coalescence;    ductile fracture;    Brown and Embury model;    X-ray tomography;    radiography;   

DOI  :  10.1016/j.msea.2007.11.050

来源: Elsevier

【 摘 要 】

A model material with a core/shell design has been fabricated. The core consists of 50 mu m diameter ZrO2/SiO2, particles in a pure aluminum matrix (99.9%) while the shell consists of particle-free aluminum. Such a design allows the sample to deform in it controlled manner. Void nucleation. growth and coalescence were precisely captured via in situ tensile tests coupled with X-ray tomography. Samples with various volume fraction of particles in their core and various notch sizes have been tested. We show that the higher the volume fraction of particles and stress triaxiality, the lower the nucleation and coalescence strains. Depending on the interactions between voids and neck geometry, void growth occurs either mainly in the tensile direction or through the formation of a diamond-like shape. Finite element simulations and slip line fields demonstrate that the shape of the voids is a result of plasticity and neck geometry. Finally, a modified version of the Brown and Embury model for coalescence is developed to take into account the lower coalescence strains at high stress triaxialities. (C) 2007 Elsevier B.V. All rights reserved.

【 授权许可】

Free