BRIGE: "Smart" Toughness Enhancement in Metal-Matrix Composites: Linking Structure, Properties and Design

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The research objective of this award is to identify the structure-property relationship between the phase transformations occurring during the deformation of a metal-matrix composite reinforced with shape memory alloys and fracture toughness. Magnesium metal-matrix composites will be fabricated into two types of fracture toughness specimens, one reinforced with pseudoelastic wires and the other with shape memory alloy wires. The phase transformations in the wires will be continuously monitored during J-integral testing through the use of electrical resistivity measurements. Concurrently, modified single fiber pullout specimens will be tested to establish a relationship between the matrix/reinforcement interfacial strength and composite toughness.If successful, the results of this research will lead to improvements in the fracture toughness of metal-matrix composites, specifically self-healing alloy composites. The design and development of a light-weight self-healing alloy composite that can repair itself in response to structural damage is critical in systems that are at present impractical to repair in service. The primary goal of this work is to utilize a mechanistic approach to identify and model the role of adaptive microstructures as reinforcements in ?smart? metal-matrix composites. This provides the opportunity and a methodology to enhance the mechanical properties of metals that currently demonstrate limited fracture toughness by processing and reinforcing these materials with adaptive elements. The proposed work provides a significant contribution towards the development of high specific strength self-healing structural metals that can be toughened using shape memory alloy wire reinforcements. An integral part of this program is the enhancement and promotion of diversity using several education initiatives targeted to students at all grade levels.