Ferroelasticity
Encyclopedia
Ferroelasticity is a phenomenon in which a material may exhibit a spontaneous strain. In ferroics
, ferroelasticity is the mechanical equivalent of ferroelectricity
and ferromagnetism
. When a stress is applied to a ferroelastic material, a phase change will occur in the material from one phase to an equally stable phase either of different crystal structure
(e.g. cubic to tetragonal) or of different orientation (a 'twin' phase). This stress-induced phase change results in a spontaneous strain in the material.
The shape memory effect and superelasticity are manifestations of ferroelasticity. Nitinol (nickel titanium), a common ferroelastic alloy, can display either superelasticity or the shape-memory effect at room temperature, depending on the nickel/titanium ratio.
Ferroics
Ferroics is the generic name given to the study of ferromagnets, ferroelectrics, and ferroelastics. Essentially the basis of this study is to understand the large changes in physical characteristics that occur in a very short temperature range...
, ferroelasticity is the mechanical equivalent of ferroelectricity
Ferroelectricity
Ferroelectricity is a property of certain materials which possess a spontaneous electric polarization that can be reversed by the application of an external electric field. The term is used in analogy to ferromagnetism, in which a material exhibits a permanent magnetic moment. Ferromagnetism was...
and ferromagnetism
Ferromagnetism
Ferromagnetism is the basic mechanism by which certain materials form permanent magnets, or are attracted to magnets. In physics, several different types of magnetism are distinguished...
. When a stress is applied to a ferroelastic material, a phase change will occur in the material from one phase to an equally stable phase either of different crystal structure
Crystal structure
In mineralogy and crystallography, crystal structure is a unique arrangement of atoms or molecules in a crystalline liquid or solid. A crystal structure is composed of a pattern, a set of atoms arranged in a particular way, and a lattice exhibiting long-range order and symmetry...
(e.g. cubic to tetragonal) or of different orientation (a 'twin' phase). This stress-induced phase change results in a spontaneous strain in the material.
The shape memory effect and superelasticity are manifestations of ferroelasticity. Nitinol (nickel titanium), a common ferroelastic alloy, can display either superelasticity or the shape-memory effect at room temperature, depending on the nickel/titanium ratio.