A micromechanical model for the ductility of plastically deforming materials containing a homogeneous distribution of brittle inclusions is developed and applied to quasi-eutectic cast aluminium alloys. The model includes a micro-macro void nucleation condition, the initial penny shape nature of the voids, and the growth and coalescence regimes. The model is validated by comparing the predictions to experimental results obtained under different levels of stress triaxiality and for different heat treatments controlling the hardness of the matrix. The material parameters are directly identified on the microstructure. A parametric study on the ductility in uniaxial tension of materials with penny shape voids demonstrates the complex couplings existing between the void nucleation condition, the state of hardening, the strain hardening capacity and the particle volume fraction.
- Aluminium alloys
- Micromechanical modelling