Efectos de la deformacion mecanica sobre compuestos de matriz de aluminio tratados termicamente (Spanish text)

A novel aluminum matrix composite reinforced with ceramic particles of AlB2 obtained through a cast process at temperatures below 800°C using commercial alloys of aluminum-boron (5 wt%. B) and aluminum-copper (33.2 wt%. Cu) was characterized. The effects of cold work prior to aging on precipitation hardening were studied using a mixture design experiment combined with split-split plot experiment. Statistical models for the hardness of the composite were produced showing an increase in hardness of the composite due to cold work and aging process as well as higher levels of boron and copper. The aging treatment effect is proportional to the amount of copper present in the material, confirming that hardness and mechanical strength can be adjusted by a combination of cold work and heat treatments. The microstructural analysis showed a good distribution of reinforcements and revealed a pattern of grain subdivision by deformation. Tensile tests were performed to corroborate the results and a dynamic strain aging behavior was observed in a solutionized sample. Finally the fracture surface was analyzed using SEM and optical microscopy, which showed that the predominant failure mode is a combination of brittle and ductile fracture.