Microstructural Characterization of Ti-6Al-4V Alloy Fiber Laser Weldments

Abstract

The quality of fiber laser welded specimens of Ti-6Al-4V alloy plates in butt joint is examined. A special kind of fixture is designed and fabricated for providing shielding gas. The microstructural analysis at various positions within heat-affected zone and in fusion zone are explored and its microstructural morphologies are compared. Due to the chronological distribution of temperature gradient, a nonhomogeneous microstructure is developed from fusion zone to base metal zone. Various kinds of microstructural morphology of martensitic structure, i.e., α′ martensite, massive α (αm), and blocky α are found in fusion zone. Also, the variations in amount of α′ martensite are found inside heat-affected zones. Maximum hardness is obtained in fusion zone due to the occurrence of higher quantity of α′ martensitic structure.