The influence of loading parameters on the deformation of the AlAl4C3 system

The influence of testing temperature in the range 20-500 deg C and of deformation rate under static conditions in the range 10 exp --1 -10 exp --5 s exp --1 on mechanical properties and substructural changes is analyzed. Experimental material consisted of aluminum, dispersion hardened with 8 vol.% of Al4C3 particles. The influence of testing temperature and deformation rate on the values of the yield point and ultimate strength was determined. Thermal dependencies of reduction of area and ductility in the temperature range 350-450 deg C and deformation rate 10 exp --1 s exp --1 indicate a considerable increase of these properties. This can be ascribed to the effect of dynamic polygonization together with sliding along grain boundaries. The parameters of the equation of state characterizing the overall influence of temperatures and deformation rates on stress at 0.2% deformation, including the apparent activation energy of the process of deformation, were evaluated. Fracture micromechanisms were influenced by testing temperature while the effect of deformation rate was unimportant. Low temperature fractures had a transcrystalline character; at temperatures > 400 deg C, the fracture had an intercrystalline character.