Fig. 1. Tensile yield stress (at 0.02% offset strain) of ceramic particle-reinforced aluminum matrix composite plotted as a function of particle size. Open and solid square symbols represent experimental data taken from Kouzeli and Mortensen (2002), whilst solid and dash lines represent curve-fitting.

Fig. 2. Length scale conditions in crystalline solids: (a) Cauchy medium; (b) higher-order medium; (c) homogenization model.

Fig. 3. Length scale conditions in particulate composites: (a) Cauchy medium; (b) higher-order medium; (c) homogenization model.

Fig. 4. Uniaxial tensile stress–strain curves of Al₂O₃–Al composite system: comparison between theory and experiment (Kouzeli and Mortensen, 2002).

Fig. 5. Tensile yield stress (at 0.2% offset strain) of Al₂O₃–Al composite system plotted as a function of particle size: comparison between theory and experiment (Kouzeli and Mortensen, 2002).

Fig. 6. Normalized initial yield stress of particulate composites plotted as a function of relative particle size η(= a/h) for v = 2.53, ρ = 0.5 and f = 0.3.

Fig. 7. Typical yield surfaces of particulate composites with size effects for v = 2.53, ρ = 0.5 and f = 0.3.

Continuum models for different length scale conditions

L = structural dimension, d = constituent (e.g., precipitate) size, R = size of representative volume element, b = dislocation spacing, D = inhomogeneity (e.g., grain, particle) size, l = (elastic or plastic) material length scale.

Material constants for Al₂O₃–Al composite system (Kouzeli and Mortensen, 2002)