Microstructure and EDS analysis on titanium/aluminium dissimilar laser welded joint subjected to age hardening

Abstract

Laser beam welding of titanium and aluminium alloy is very much needed for aerospace and automotive industries due to its high strength and light weight. The dissimilar welding is having a bearing on high temperature at the weldment and grain coarsening may cause if thermal cycle is not checked. In order to maintain good weld joint properties, phase transformation during rapid thermal cycles is required. Such cycles occur during welding of titanium/aluminium dissimilar sheets and age hardening heat treatment after welding. Titanium and aluminium alloys are sensitive to heat due to their difference in melting temperatures. This may cause changes in microstructures in weldment. The aim of this study is to analyse the changes in titanium (TI6AL4V) and aluminium (AA2024) alloy thin sheets welded joint using SEM and EDS studies before and after age hardening heat treatment. From the results, it is observed that laser beam focusing from titanium side gives well refined age hardened structure and EDS reveals that the bond is metallurgical one.