Abstract
Changes in the strain and fracture mechanism during tensile testing were investigated in dispersion strengthened Al- Al₄C₃ system. Al materials with volume fraction of 4 and 12 vol.% of Al₄C₃ were tested at temperatures from 293 to 673 K at different strain rates ranging from ε = 2.5x10^-5 to ε = 10^-1 s^-1. At room temperature, the strain was controlled by dislocation movement and interactions. Work hardening characterized the first part of the strain curve and the second part was characterized by the local strain in the neck. At higher temperatures and strain rates, the number of strain mechanisms was increased by a mechanism attributed to a dynamic recovery process. Fracture mechanism changes depend on temperature and strain rate. At lower temperatures the dispersion strengthened Al-Al₄C₃ system was characterized by transcrystalline fractures. Increase of the test temperature to 523 K and over that, led to intercrystalline fractures for low strain rates ε = 2.5x10^-5 s^-1.

Key words
dispersion strengthened materials, fracture mechanism, SEM analysis

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