Investigations on surface integrity of AA7075 with Al2O3 SiC reinforcements processed through friction stir processing

Abstract

Manufacturing components with desired hardness and strength is the major need especially for automotive and aerospace applications In these areas lower friction high corrosion resistance and lower erosion rate with minimum conductivity are essential characteristics To meet the above requirements the present research aims to investigate the characteristics of AA7075 reinforced with different weight ratios of Al2O3 and SiC processed through Friction Stir Processing FSP The essential characteristics are obtained through the modified microstructure attained during FSP due to the action of dynamic recrystallization on AA7075 AA7075 surface hybrid composites are fabricated at a tool rotational speed of 1000 rpm and travelling speed of 56 mm min with 2º tool tilt angle Processing temperature is analyzed using the thermal imager during the experimentation A linear trend of increase in temperature is noted along the longitudinal axis and it is attributed to the thermal conductivity of AA7075 Microstructural examination of specimens illustrates the formation of fine grains in the nugget/stir zone along with homogenous distribution of reinforcement particles It is noted that the incorporation of Al2O3 particles in base matrix improves oxide film formation Macrostructure shows an improved bonding effect in the retreating side than the advancing side of the FSP zone X Ray Diffractometer XRD analysis reveals the presence of both the reinforcements in the base matrix based on the weight ratios MgZn2 and AlCuMg precipitates newline