Friction stir processing (FSP), a process, derived from the friction stir welding (FSW) process, is an emerging novel, green and energy efficient processing technique to fabricate surface composite. In the present investigation, FSP technique has been used for fabrication of surface composites, using aluminium 7075 as parent metal and Boron Carbide (B4C) powder particles as reinforcement., Aluminium 7075 has been selected as matrix phase, as being widely used by automotive and aerospace application and having the highest strength among all commercial Al alloys. In present paper, details about the fabrication of Al 7075-T651- B4C surface composite for various combination of tool rotation, tool travel speed and number of passes have been discussed. The same being intended to improve hardness and thereby wear resistance. The fabricated surface composites are examined for microstructure using image analyser, and found friction stir processed zone with a few defects. It is also observed that the average hardness of friction stir processed surface composite was 40 – 70% higher than that of parent metal (75 – 80 HV). Wear Resistance is found to be improved by 100% compared to parent metal. The increase in same is attributed to B4C particles dispersed in aluminium matrix and grain strengthening mechanism

Friction stir processing (FSP) is a novel technique for refining the microstructure. In this study, the effect of FSP process parameters such as tool rotation, traverse speed and tool tilt on resulting grain size, microstructure and superplastic behavior of high-strength thick Al-Zn-Mg-Cu alloy is reported. The microstructure examination of the stir zone (SZ) was performed by optical as well as scanning electron microscope. Microstructure variation attributed to different process parameters is reflected in the SZ. It is observed that grain size increases with increasing tool rotation speed, and decreases with increasing traverse speed. However, tool tilt has no significant effect on grain size. Moreover, at higher tool tilt distorted grains were observed in microscopic images. The highest average value of hardness in the SZ is obtained for low heat input value corresponding to higher tool rotation and traverse speed. In this study, hardness has shown no dependency on the grain size of the SZ due to the strengthening of phase particles. Process parameter of 1500 rpm, 31.5 mm/min and 2° tool tilt (low heat input) only exhibited superplastic elongation of 225% at a superplastic condition of 400°C and 3 × 10⁻⁴ s⁻¹ because of an appropriate material flow without any defect.