Wire electric discharge machining (WEDM) technique is a fast-growing, advanced manufacturing process which is used for machining of hard materials including various alloys of steel, nickel, tungsten, cubic boron nitride, metal matrix composites (MMC's), superalloys, and ceramic materials. Moreover, it is employed for machining complex profiles and micromachining of hardened materials which are not feasible by various conventional machining processes. Generally, this process is employed to machine electrically conductive materials but during this scenario, it is also being used for machining of electrically low conducting and non-conducting ceramics including silicon carbide, aluminium oxide, silicon nitrate, and zirconium oxide ceramics by modifying the WEDM method with assisted electrode technique or forming composite of conductive and non-conductive materials. This paper presents a comprehensive review on the influence of several WEDM control factors including pulse-on time, pulse-off time, wire feed rate, peak current, wire tension, type of wire (tool) materials, types of base materials and types of powder mixed dielectric fluids on the output responses such as surface roughness (Ra), material removal rate (MRR), width of cut (kerf), wire wear ratio (WWR), wire breakage, microstructural defects, recast layer thickness, and thermal deformation. Moreover, various simulation methods, post processing methods and optimization of WEDM parameters using various techniques were discussed and at last this paper shapes the important recommendations and upcoming developments in WEDM.

In the present study, friction stir welding (FSW) of butt and scarf joints of Al 6063-T6 were investigated. Five different tool pin profiles (cylindrical, tapered cylindrical, square, triangular, and hexagonal) were applied for performing welding. Scarf joint, being a new joint configuration, was used and effect of pin profiles was investigated on this type of joint configuration. The effect of pin profiles on microstructure, micro-hardness, impact and tensile properties of friction stir welded Al 6063-T6 was investigated. Scanning electron and optical microscopy were employed to characterize the different zones of welded joints. A thorough discussion on correlation between mechanical properties and microstructure has been made. In addition, the formation of various defects during the FSW was discussed with the help of fractography of the fractured surfaces.