Material properties of nanostructured materials

Nanomaterials are the subject of numerous studies, there is significant research currently underway as they have a wide range of applications. Their importance has been particularly highlighted in articles [MA 4 026] “Nanomaterials: structure and development” and [MA 4 027] “Nanomaterials: proprieties and applications” in Techniques de l'Ingénieur/Engineering Techniques . This is a rapidly developing field and covers a wide variety of issues; therefore, this article provides additional information primarily concerning the mechanical properties of nanostructured materials, and selected development techniques.

The term ‘nanomaterials', refers to both materials with an extreme division state and materials with nanoscale structures. The issues concerning these different types of nanomaterials are not the same. Depending on the case, they can be physical, chemical, or mechanical. Discussing all of them would result in a disparate presentation. It is therefore preferable to limit this presentation to one aspect, the aspect of mechanical properties, with the specific aim of using nanomaterials in mechanical functional structures. It is for this reason, it will mainly involve the consideration of nanostructured materials, however, not all of them. We can broadly classify nanomaterials into four categories according to their dimensionality  :

• dimension 0 for materials containing nanoscale clusters,

• dimension 1 for those incorporating nanotubes or nanostructured wires and multilayers exhibiting various nanometric thicknesses,

• dimension 2 for nanostructured layers,

• dimension 3 for equiaxed nanostructured solids. Keeping in mind the mechanical function, clusters and nanotubes act as reinforcements in materials with a conventional microstructure. It is here, that wire and solid equiaxed nanostructures will be principally dealt with. Additional classification occurs based on the materials: single-phase or poly-phase