Microstructural characterization and indentation creep behavior of friction stir modified Al surface with iron powder

Iron powder mixed with methanol is spread on Al base plate and Friction Stir Processing (FSP) is carried out with a constant load of 8kN, imposing a feed rate of 0.3mm/s at different tool rotational speed. Processed materials are characterized for revealing the microstructural features. Further, indentation creep behavior was assessed both on the base metal and processed zone using tungsten carbide indentor at the temperature of 30 and 100°C. Creep curves are generated and steady state creep rate (SSCR) values at two different temperatures are determined which in turn enables to find out activation energy for creep process. The results of x-ray diffraction reveal the formation of solid solution and an intermetallic phase (Al₁₃Fe₄) accompanied with the process of grain refinement. The results of impression creep test indicate that SSCR for processed zone is more than that for base metal. Further, if tool rotation speed is increased, the activation energy for creep decreases.