Selective Reinforcement Using Metal Matrix Composite Prepreg and Ultrasonic Additive Manufacturing

The aerospace industry frequently refers to the need for lightweight, advanced structures for achieving aggressive fuel economy standards.  Open literature further emphasizes the need for developing new materials that can be processed using advanced, cost-effective manufacturing methods.  New materials that optimize a range of properties, including mechanical strength, stiffness, and damage tolerance, will reduce parasitic mass and increase system performance.  Recent work has addressed these needs through the combination of a metal matrix composite (MMC) prepreg tape feedstock called MetPreg® and a novel solid state 3D printing technology called ultrasonic additive manufacturing (UAM).  The combination of these technologies has led to enhanced metallic structures through selective reinforcement (SR), which consists of adding a high-performance material to structures to achieve local stiffening and strengthening.  MetPreg is a composite material with density comparable to aluminum and strength and stiffness comparable to steel.  UAM is a 3D printing process that uses sound to merge layers of metal drawn from featureless foil stock.  The process produces true metallurgical bonds with full density and works with a variety of metals.  Current research is focused on design principles for effectively incorporating MetPreg into structures in order to maximize mechanical performance while minimizing costs.  Additionally, studies have been completed to measure real world performance of MMC-enhanced structures manufactured using 3D printing.