Mechanical and Microstructural Evolutions of the Laser Deposited Titanium Layers under Various Shielding Atmospheres

Abstract

Direct laser melting process is a kind of prototyping process whereby a 3-D part is built layer-wise by melting the metal powder with laser scanning. The properties of laser melted layer are found to be strongly dependent upon the types of shielding gas used. In this study, the effects of shielding gases on the mechanical and microstructural properties of the deposited titanium layers have been investigated. The laser remelting process has also been implemented at various shielding atmospheres to investigate the changes in surface roughness and hardness of deposited layers. The characterization of laser processing parameters, such as laser power, scan rate, gas flow rate, powder layer thickness, beam spot size and hatch distance, is proved to be useful in controlling the mechanical and microstructural properties of the deposited layer.