Quality and Hardness of Aluminum–Zinc Explosive Welding under Different Conditions

This study explores the influence of different explosive thicknesses, te (38 and 47 mm) and standoff distances, SOD (5 and 10 mm), on the interface macrostructure and Vickers micro-hardness of commercially pure1050 aluminum and zinc explosive welding. At lower explosive thickness combined with a minimal standoff distance, the weld interface exhibited a predominantly straight morphology, indicating limited plastic deformation and interfacial instability. In contrast, joints fabricated using a higher explosive thickness (47 mm) developed a characteristic wavy interface, largely independent of the standoff distance, reflecting enhanced collision velocity and jetting behavior. Under conditions of higher explosive thickness and increased standoff distance, a continuous molten interfacial layer was observed, consisting of Al–Zn intermetallic compounds such as AlZn and Al2Zn3, as confirmed by energy dispersive X-ray analysis (EDAX) and X-ray diffraction (XRD). Vickers micro-hardness measurements revealed a pronounced increase in hardness with increasing explosive thickness, with peak hardness values recorded in the vicinity of the weld interface (20 μm) due to severe plastic deformation. Furthermore, all experimental welding conditions were found to be placed within the successful regimes of the weldability window, an analytical estimation, enabling reliable prediction of interface morphology.