Effect of fibre laser welding parameters on the microstructure and weld geometry of commercially pure titanium

Abstract

The primary purpose of the study was the metallurgical characterization of laser welds. The weldability of commercial production of pure titanium and titanium alloy (CP-Ti) has also been examined. In this research, the laser fibre method was used to weld sheets of pure titanium, and then microscopy and scanning electron microscopy were used to study the changes in the microstructure, the depth of weld penetration and the width of the weld area with changing welding parameters. The results proved that increasing the laser power significantly increases the depth of weld penetration and weld width. When the heat input is increased, the shape of the weld pool changes from a V shape to an hourglass shape. It was also observed that the depth of the crater formed increases with the increase in the laser power due to the increase in the melting and evaporation of the weld metal. Increasing the welding speed also has a negative impact on the weld geometry because it reduces the heat input and absorption of laser energy by the weld metal and thus reduces the melting of the metal. The microstructure of the fusion zone consists of acicular α. Fine grains formed in the weld centre at low heat input; the granules became columnar-like. Since commercially pure titanium contains a small amount of beta-phase stabilizers, the cooling rate is extremely high for martensite to occur. In the future, it is recommended to study the effect of changing welding parameters on the mechanical properties of pure titanium because of its great importance in industrial and medical applications. Studying the effect of changing laser power and welding speed on the metallurgical properties of pure titanium, and consequently its effect on the mechanical properties of welds.