Intergranulaire

Intergranular is an adjective used in materials science to describe phenomena that occur at the interfaces between grains in a polycrystalline material. Grains are the individual crystals that make up most metals, ceramics, and composites; the interfaces where they meet are grain boundaries. Intergranular processes occur along these boundaries or across their junctions and are often distinct from transgranular processes that cut across grains. The English term is intergranular; in French the corresponding adjective is intergranulaire.

Common contexts include intergranular corrosion, where attack runs along grain boundaries; intergranular fracture, in which cracks propagate along boundaries; and diffusion or precipitation phenomena concentrated at boundaries. Intergranular corrosion is frequently linked to sensitization, impurity segregation, or precipitation of second-phase particles at boundaries, which can deplete protective alloying elements locally and promote galvanic attack. Intergranular fracture indicates a boundary-weakness or embrittlement situation, often associated with specific heat treatments or long-term exposure. Grain boundary diffusion, by contrast with lattice diffusion, can dominate creep, sintering, and aging processes at lower temperatures. The study of intergranular behavior informs alloy design, heat-treatment protocols, and failure analysis.

Characterization of intergranular phenomena typically employs microscopy (SEM/TEM), electron backscatter diffraction (EBSD), and chemical analysis to assess boundary structure and chemistry and to determine boundary types that are most susceptible to degradation.