In-Situ Synthesis of Metal Matrix Composites Via Direct Metal Deposition

Metal matrix composites provide many desirable properties and facilitate the creation of strong, lightweight components by reinforcing a lightweight, though metal with hard and wear resistance ceramic particles.  Metal matrix composite coatings are also being considered to create wear and oxidation resistance surfaces on various softer substrates.   Specialized MMC coatings can be made by laser cladding using multi-component powder mixtures. 

Direct deposition of the metal matrix composites (MMC) via laser cladding offers some unique advantages: 

–        First, if we inject the matrix and reinforcing particles from two powder feeders into the same nozzle, we can control the precise volume fraction of reinforcing particles and mix them evenly with the matrix powder.   

–       Secondly, this processing technique allows for in-situ deposition of MMNC layers on selected areas of the target substrate.  This can allow for imparting “engineered properties” on the part, where the substrate part of light metal maintains good toughness, while the surface layer of MMC provides good mechanical, tribological and anti-corrosion properties.

–       The method can be used for thin or thick layer coating or fabrication of 3D parts through multi-layer deposition.

–       Furthermore, the mass feed rate of the reinforcing powders can be adjusted as necessary, resulting in the formation of functionally gradient MMC.

The paper describes the recent development on predictive modeling of laser direct deposition and some recent experimental results.