Mechanical and microstructural characterization of high reinforcement content aluminum metal matrix composites in extreme conditions

Abstract

The final motivation of the research in which is framed this work is to optimize the friction-stir welding, FSW, process and its implementation in conventional machining centers. The FSW process occurs in the solid state at high temperature and by severe plastic deformation (high deformation at high rate) of the material. In this work we have studied the behavior at high temperature and high deformation rates of metal matrix composite materials 2124Al-25%SiC and 6061Al-40%SiC. The plastic deformation capacity in the high temperature regime has been studied by tensile, compressive and torsion tests at temperatures in the interval 300-475ºC and high strain rates, at 1s-1 and above. Large plastic deformations have been obtained without the appearance of serious defects despite the high reinforcement content. The good behavior in the conditions studied presumes the good weldability by means of the FSW technique. On the other hand, the data of the microstructure have allowed determining some of the constants that appear in the creep equation. Finally, we have succeeded in explaining the creep behavior through models developed for this technique from the experimental results.