1. General information on hardening precipitation

1.1 Precipitation for metals

Pure metals with a simple crystallographic structure (face-centered cubic, face-centered cubic, compact hexagonal) have intrinsically weak mechanical properties, due to the ease with which dislocations can propagate. The properties of these metals are improved by the addition of alloying elements and thermomechanical treatments. These enable the nature and spatial distribution of the microstructure to be controlled, and thus the obstacles to plastic deformation, so as to increase the yield strength without sacrificing too much the other properties of use (ductility, toughness, etc.).