New Chemistries for Metal Matrix Composites

In this research program new synthesis methods will be used to enable new bulk and surface chemistries of alloys and metal matrix composites (MMCs) made by laser powder bed fusion (LPBF). In the LPBF method, metal parts are essentially 3D printed with a laser from metal powders, allowing the creation of metal parts with complex shapes and with properties not otherwise attainable. However, the composition of LPBF parts is limited by the spray atomization method used to make metal powders. In addition, although highly desirable, the surface chemistry of Al makes Al-based alloys amongst the most difficult to process by LPBF. New chemistries are required to solve these issues. It would also be highly desirable to make LPBF parts from metal matrix composites (MMCs), in which reinforcing ceramic particles are incorporated in the alloy. MMCs are highly useful for lightweight structural components to increase fuel economy in aircraft and automobiles. However, MMCs are generally incompatible with LPBF methods. In this research program new synthesis methods will be used to significantly increase the chemical compositions of alloys obtainable by the LPBF method. This research is enabled by dry particle microgranulation, recently developed in the Obrovac lab, which can convert ball milled powders into smooth, spherical powders with morphologies that are compatible with LPBF. In addition, surface coatings, internal composition gradients and even ceramic reinforcing particles may be introduced into the particles. This enables a wide variety of alloy matrix chemistries, surface chemistries and reinforcing chemistries to be used in LPBF, further enabling new MMCs to be made by this process. The precise control of particle morphology, independent of particle composition, also allows fundamental studies of the chemistry of the LPBF process. These new methods have never been applied to the synthesis of alloys. This research program will combine bulk alloy chemistry, surface chemistry, alloy synthesis, and nano-scale particle design, giving students a rich and valuable training experience. Outcomes of this research program are the production of new alloy parts using compositions and microstructures that have been otherwise hindered because of cost, poor particle flow characteristics or safety issues. This could greatly benefit the environment and Canadian automotive and aerospace industries by providing inexpensive and lightweight high strength parts; thereby reducing cost, improving fuel economy and improving the range of EVs.