Laser powder micro-deposition of compositional gradient Ti–Cr alloy

Laser powder deposition allows preparing fully dense metallic parts in a layer-by-layer additive manufacturing manner. The method presents great flexibility in controlling the materials composition as well as its microstructure and properties. In this paper, composition gradient thin walls from Ti to Ti–60 at.%Cr were prepared by the laser powder micro-deposition process. The microstructure, phase constitution, micro hardness, and modulus were characterized by scanning electron microscope (SEM), micro X-ray diffraction (micro-XRD) and ultra micro indentation testing along the composition gradient direction. The results show that the composition along the wall height change as predetermined. Metastable β-Ti(Cr) was formed for compositions with more than 25 at.%Cr. TiCr2 phase was formed and its percentage increased with further increase of Cr content. The hardness and modulus changed conformably with the composition gradient.