Compositional Changes and Microstructure Evolution of Ti6Al4V-Inconel718 Functionally Graded Materials by Laser Additive Manufacturing

Abstract:

Ti6Al4V/Inconel718 functionally graded materials were prepared by laser additive manufacturing technology. The composition, phase composition, microstructure and microhardness of the gradient materials were studied. The research shows that a series of phase transitions occur along the composition gradient direction: α+β→α+β+Ti₂Ni→β+TiNi→γ, and the transition layer is mainly composed of TiNi and Ti₂Ni and binary phases such as Ti-Cr and Ti-Fe. The composition of the mixture; the microstructure from the bottom to the top of the material has undergone a transformation from Widmanst?tten α-laths to fine dendritic structure; the microhardness test of the deposited structure shows that the transition layer with the higher Ti₂Ni phase area fraction is the hardest. This study found a maximum of 823 HV.

Key words:laser additive manufacturing; functionally graded material; Ti6Al4V/Inconel718; composition; microstructure