Design and Fabrication of Functionally Graded Material from Ti to γ-TiAl by Laser Metal Deposition
Abstract
Functionally graded material (FGM) is one kind of advanced material characterized by a
gradual change in properties as the position varies. The spatial variation of compositional and
microstructure over volume is aimed to control corresponding functional properties. In this
research, when 100% γ-TiAl was directly deposited on pure Ti substrate, cracks were formed
within the γ-TiAl layer. Then a six-layer crack-free functionally graded material of Ti/TiAl was
designed and fabricated by laser metal deposition (LMD) method, with composition changing from
pure Ti on one side to 100% γ-TiAl on the other side. The fabricated FGM was characterized for
material properties by a variety of techniques. The chemical compositions, microstructure, phases,
and hardness of the composite were characterized by Scanning Electronic Microscope (SEM),
Optical Microscope (OM), Energy Dispersive X-ray Spectroscopy (EDS), and hardness testing.
The microstructure and chemical compositions in different layers were studied.