5. Transformation

5.1 Homogenization

The first step before processing consists of homogenization (high-temperature heat treatment), which has two objectives:

• the dissolving of intermetallic phases resulting from solidification in the inter-dendritic zones and detrimental to the metal's use;

• diffusion of alloying elements between the dendritic and inter-dendritic zones.

For both these reasons, this homogenization stage is carried out at high temperatures, allowing harmful phases to be brought into solution. In addition, in order to obtain sufficient diffusion of the alloying elements, this stage must last a relatively long time (24 to 72 h). This treatment is followed by slow cooling to...