In-Situ Synthesis of Functional Gradient Metal Matrix Composites of Titanium and Inconel Reinforced by TiC by Additive Manufacturing

In recent years, the interest in additive manufacturing processes has grown significantly due to their unique attractive attributes and versatility.  Laser-based additive manufacturing (AM) processes can provide unique capabilities of synthesizing materials in-situ while building three dimensional shapes.  This talk provides latest developments in synthesizing various metal matrix composites (MMC) in-situ and their functionally gradient structures.   Functionally gradient composites provide gradual changes in thermal and mechanical properties as well as some refinement in the matrix material.  Two case studies are shown including Titanium/TiC MMC and Inconel 690/TiC MMC.  The microstructures and distributions of unmelted TiC (UMT) particles and pores were characterized with optical microscopy, scanning electron microscopy and energy dispersive spectroscopy. The detailed microstructural analysis is shown in terms of compositions and properties with the layer height, thus demonstrating AM capabilities for synthesizing the materials in-situ while building three-dimensional structures.   Microstructural details such as grain distributions and phase changes as well as mechanical properties such as hardness and tensile strengths are disseminated in terms of initial TiC percentage and laser processing conditions.   This work demonstrates the capabilities of AM for controlling mechanical and thermal properties of MMC in-situ as needed.