Strain-detecting composite materials

摘要

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° C. to form the composite material.

主权项

1. A composite material comprising:
a structural material; and a plurality of particles formed from a shape-memory alloy and embedded in said structural material such that the ductility of the structural material is not adversely affected; wherein the composite material is configured such that when a crack forms in the composite material with a crack tip process zone at a tip of the crack and an adjacent region disposed adjacent to said crack tip process zone, such that when the crack tip process zone reaches one of the plurality of particles formed from the shape-memory alloy, said shape-memory alloy within said crack tip process zone changes crystallographic phase from austenite to martensite within said crack tip process zone in response to a predefined critical macroscopic average strain within said crack tip process zone, and wherein a strain in said adjacent region is below the predefined critical macroscopic average strain, and said shape-memory alloy within said adjacent region does not change crystallographic phase from austenite to martensite within said adjacent region; and wherein said shape-memory alloy having a changed crystallographic phase from austenite to martensite does not revert to austenite from martensite upon removal of said predefined critical macroscopic average strain.