## 1 Introduction
The choice of these welding parameters will have a significant impact on the manner of heat generation and material flow during the friction welding process, as well as the microstructure, residual stress, and structural integrity of the weld. The influence of each parameter of friction welding is greatly dependent on the type of material being connected. The friction welding process can accommodate a wide range of materials and their complexity. The application of this method to distinct materials yields particular effects. Researchers investigated the properties of FRW through the weld center zone (WCZ), thermomechanically heat-affected zones (TMAZ), and the heat-affected zone (HAZ). At certain material joints, the WCZ area may undergo dynamic recrystallization (DRX), although this did not occur at the TMAZ or HAZ. On another condition, when dissimilar materials are joined, the high temperature at the weld line combined with the severe deformation is also likely to promote the formation of intermetallic compounds [10]. The microstructure and mechanical properties of each zone are highly dependent on the base material and process conditions [11]. The effect of each process parameter on the quality of the connection, including mechanical qualities, microstructure, and other chemical properties, varies with the type of material being connected. Optimization of the process parameters has always been vital in the friction welding process. By the optimization of friction welding parameters, the materials' weld quality can be increased; however, not all effects of these factors are not fully understood. These optimization studies are yet to be completed. Friction welding has been employed and developed in the production of components for the automotive, power generation, aerospace, marine, oil sectors, nuclear systems, and numerous engineering applications [9; 20; 21; 22; 23] due to its advantages. Some examples of components that apply friction welding include engine blades and disks, cylinder tubes for hydraulic cylinders, drive shafts, pipes and nozzles, drill pipes, marine engine valves, and impellers for the turbo-supercharger of a diesel engine. Friction welding has been used to connect a variety of related materials, including superalloys and various steels, such as mild steel to mild steel, stainless steel, and mild steel to stainless steel [24; 25], aluminum alloys, copper alloys, and titanium alloys [7; 26; 27]. This method has also been applied to a variety of dissimilar material combinations, including aluminum and magnesium alloy [13], pure aluminum and copper [7], dissimilar steel alloys, superalloy-steel, steel-aluminum [6], tungsten-mild steel [28], tungsten and aluminum alloy [29], aluminum-titanium [22], magnesium alloy and stainless steel [30]. In addition, FRW is used to link metal and non-metallic materials [11; 31], including Al6061 alloy with alumina-YSZ composite [32], steel and ceramics [33], and copper and alumina [34]. Joining these materials using friction welding has yielded different amount of success and advantages. To make use of the benefits of this friction welding, it is therefore possible for numerous researchers to continue developing and analyzing the welding of various sorts of diverse materials. In addition, zinc is a relatively active metal whose compounds are stable. It was discovered considerably later than other less reactive metals, such as gold, copper, iron, silver, and lead. However, it is not found in nature. Zinc is typically regarded as a rather weak metal; but, when alloyed with stronger materials and subjected to a particular treatment, its impact strength can be increased. Pure zinc has a tensile strength ranging from 28 MPa (cast) to 246 MPa (hard temper), an elasticity modulus of 70 MPa, a melting point of 419.5 \({}^{\circ}\)C, and excellent corrosion-resistance [35]. According to the industry, zinc alloys were employed in a variety of ways. The quality of zinc will also decide whether it could be used for automotive, medical, or construction purposes.