Study of Tool Wear in Friction Stir Processing of Metal Matrix Composites—A Review

The tool wear is an important issue in the fabrication of the metal matrix composites (MMCs). Friction stir processing (FSP) is a technique utilized to manufacture MMCs. It refines microstructure and enhances mechanical properties and also removes casting defects. Mostly, FSP has been carried out in non-ferrous alloys like aluminum, magnesium, copper, etc., to improve their strength and hardness. Now, this process is implemented for metals like steel and titanium also. During the rotation and traverse action, the FSP tool comes in contact with the ceramic powder which is much harder and sharper resulting in tool wear. The tool wear depends on the interaction between the tool and the workpiece materials. The tool geometry, FSP parameters, and the reinforcement material also play an important role in tool wear. The selection of the tool type, tool material, and tool geometry is important to produce a good quality workpiece. This selection depends on the stir zone temperature, wear resistance, material toughness, etc. This study aims to investigate the rate of tool wear, tool types, tool material, and tool dimensions in FSP of surface composites and metal matrix composites. FSP of hard materials is still a challenging task. More studies of tool design, tool wear, and selection of tool material are still required to be conducted to make this process more useful in future.