Composites have been found to be the most promising and discerning material available in this century. Presently, composites reinforced with fibers of synthetic or natural materials are gaining more importance as demands for lightweight materials with high strength for specific applications are growing in the market. Fiber-reinforced polymer composite offers not only high strength to weight ratio, but also reveals exceptional properties such as high durability; stiffness; damping property; flexural strength; and resistance to corrosion, wear, impact, and fire. These wide ranges of diverse features have led composite materials to find applications in mechanical, construction, aerospace, automobile, biomedical, marine, and many other manufacturing industries. Performance of composite materials predominantly depends on their constituent elements and manufacturing techniques, therefore, functional properties of various fibers available worldwide, their classifications, and the manufacturing techniques used to fabricate the composite materials need to be studied in order to figure out the optimized characteristic of the material for the desired application. An overview of a diverse range of fibers, their properties, functionality, classification, and various fiber composite manufacturing techniques is presented to discover the optimized fiber-reinforced composite material for significant applications. Their exceptional performance in the numerous fields of applications have made fiber-reinforced composite materials a promising alternative over solitary metals or alloys.

Friction-based welding processes are considered as very efficient solid-state metal joining processes due to soundness of the welded joint with remarkably less energy consumption and environmentally friendly. The terminology behind these processes is to make use of elevated temperatures caused by the mechanical friction at contacting surfaces to fuse materials together. Several different friction-based welding techniques are classified briefly explaining their mechanisms to show a comparison between friction welding (FRW) and friction stir welding (FSW). In FRW contact between the specimens itself induce friction, while FSW uses a non-consumable rotating tool to fuse material at the junction. Numerous advantages and drawbacks exhibited by both the processes are compared by overviewing the current researches. Also extensive focus on the various factors influencing the properties of FSW joints such as rotational speed, welding speed, axial force, tool geometry, and defects are studied. FSW displayed superiority in welded joints as regards adaption to modern technologies, optimized process parameters, and the ability to join a wide variety of dissimilar metals and alloys.