Interest in additive manufacturing (AM) has dramatically expanded in the last several years, owing to the paradigm shift that the process provides over conventional manufacturing. Although the vast majority of recent work in AM has focused on three-dimensional printing in polymers, AM techniques for fabricating metal alloys have been available for more than a decade. Here, laser deposition (LD) is used to fabricate multifunctional metal alloys that have a strategically graded composition to alter their mechanical and physical properties. Using the technique in combination with rotational deposition enables fabrication of compositional gradients radially from the center of a sample. A roadmap for developing gradient alloys is presented that uses multi-component phase diagrams as maps for composition selection so as to avoid unwanted phases. Practical applications for the new technology are demonstrated in low-coefficient of thermal expansion radially graded metal inserts for carbon-fiber spacecraft panels.

The current work provides an overview of the state-of-the-art in polymer and metal additive manufacturing and provides a progress report on the science and technology behind gradient metal alloys produced through laser deposition. The research discusses a road map for creating gradient metals using additive manufacturing, demonstrates basic science results obtainable through the methodology, shows examples of prototype gradient hardware, and suggests that Compositionally Graded Metals is an emerging field of metallurgy research.

Despite their promising mechanical properties and ability to be manufactured like plastics, bulk metallic glasses (BMGs) are slow to emerge as a structural engineering material. Because BMGs properties are highly correlated with processing, it is necessary to test them in a relevant engineering application. In the current work, CuZrbased BMGs are developed with excellent wear performance when used as gears. It is shown that in order to optimize the wear performance of these gears, toughness should be maximized. This contrasts the conventional design strategy, where wear performance increases with increasing hardness. Finally, a new low-cost manufacturing method for casting net-shaped macroscale gears is developed.