Laser beam welding is a non-conventional welding process with high applicability to produce quality welds. An attempt is made to weld TI6AL4V (Ti) and AA2024 (Al) dissimilar sheet metal joints and studies have been made to analyze the structure in the weldment. Structural studies such as macrostructure and micro studies are undertaken. The extend of a metal mix in the fusion zone is also studied using Energy Dispersive Spectroscopy (EDS). Micro studies using Scanning Electron Microscope (SEM) reveal that higher weld speed brings grain refinement leading to the enhanced strength. SEM and EDS analysis further reveal that laser beam focusing from Ti side instead of Al side brings good quality weldment.

Laser beam welding of light weight and high strength Ti and Al alloy is very attractive for aerospace and automotive industries. The development of dissimilar welding is having a bearing on maximum temperature at the weldment and heat transfer rate in heat affected zone. Also grain coarsening may cause if the thermal cycle is not properly checked. For maintaining good mechanical properties of the weld joints, phase transformation during rapid thermal cycles is required. Such cycles occur during welding of Ti/Al sheets and heat treatment after welding. Ti and Al alloys are sensitive to heat due to their high difference in melting temperatures. This may cause changes in microstructures infusion and heat affected zones. The aim of this study is to examine the changes in the microstructures, heat affected zones of the TI6AL4V (Ti) and AA2024 (Al) alloy thin sheets welded joint using SEM and EDS analysis of different variants before and after precipitation hardening. Test results reveal that laser arc, focusing on Ti side gives better-refined age hardened structure than from Al side, and EDS analysis is also supporting the view.