United States of America As Represented by the Administrator of Nasa

Peter L Messick

Joel A Alexa

Robert S Piascik

Edward H Glaessgen

Stephen W Smith

Michael R Horne

Richard Keith Bird

John A Wagner

Benjamin T Hailer

Marcia S Domack

Terryl A Wallace

Various embodiments provide methods in which a metal matrix composite (MMC) material is incorporated into a metallic structure during a one-step near-net-shape structural forming process. Various embodiments provide in-situ selective reinforcement processes in which the MMC may be pre-placed on a forming tool in locations that correspond to specific regions in the metallic structure. Various embodiment near-net-shape structural forming processes may then be executed and result in various embodiment metallic structural components with selectively-reinforced regions that provide enhanced mechanical properties in key locations.

In-situ selective reinforcement of near-net-shaped formed structures

A composite material includes a structural material and a shape-memory alloy embedded in the structural material. The shape-memory alloy changes crystallographic phase from austenite to martensite in response to a predefined critical macroscopic average strain of the composite material. In a second embodiment, the composite material includes a plurality of particles of a ferromagnetic shape-memory alloy embedded in the structural material. The ferromagnetic shape-memory alloy changes crystallographic phase from austenite to martensite and changes magnetic phase in response to the predefined critical macroscopic average strain of the composite material. A method of forming a composite material for sensing the predefined critical macroscopic average strain includes providing the shape-memory alloy having an austenite crystallographic phase, changing a size and shape of the shape-memory alloy to thereby form a plurality of particles, and combining the structural material and the particles at a temperature of from about 100-700&#xb0; C. to form the composite material.

Strain-detecting composite materials

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Poquoson, VA, United States of America

Peter L Messick