Fabrication of functionally graded properties by direct laser melting of compositionally selective metallic powder

Functionally graded properties are characterized by the variation in composition and structure gradually over volume, resulting in corresponding changes in the properties of the material. Direct laser melting (DLM) process is a kind of prototyping process whereby a 3-D part is built layer-wise by melting the metal powder with laser scanning. DLM can directly build full-density and high-performance complex metal parts from CAD solid model without using any molds and tools. The aim of the study is to demonstrate the possibility to produce functionally graded properties in gear-parts through the direct laser melting of compositionally selected metallic powders. Properties of manufactured parts depend strongly on each single laser-melted track and each single layer. Therefore effects of the processing parameters such as scanning speed and laser power on single tracks formation are explored. For the fabrication of gear, building direction and hatch angle have been mainly controlled. Hardness test and EDX analysis were carried out on cross-section of fabricated gear to characterize functionally graded properties. From the analysis, functionally graded properties can be successfully obtained by DLM of selected metallic powders having different compositions.