Influence of damage on the tensile behaviour of pure aluminium reinforced with ≥40 vol. pct alumina particles Original Research Article

Particle reinforced composites are produced by infiltrating Al2O3 particle beds with high purity Al (99.99%). These materials feature 40–60 vol. pct reinforcement homogeneously distributed in a pore-free matrix. Their tensile behaviour is studied as a function of reinforcement size and shape. Internal damage, in the form of particle fracture and matrix voiding, occurs from the onset of plastic straining. Its evolution with strain is monitored through changes in (i) stiffness and (ii) peak stress after incremental plastic straining and annealing. The influence of damage on the flow curves of the composites can be accounted for using basic postulates of continuum damage mechanics. Failure strains vary between 2 and 4%, and are a function of the rate of damage accumulation. An expression is derived to predict elongation to failure of damaging materials that fail by tensile instability, which gives good agreement with the experimental observations.