1. Main heat treatment parameters

For an alloy of given composition and purity, the main heat treatment parameters are temperature and time (maximum temperature, holding time, cooling rate).

• Temperature has an essential (exponential) influence on the rate of diffusion in the solid state. A high temperature helps homogenize compositions by reducing foundry segregations. It also enables residual stresses to be reduced and recrystallization to take place. Finally, it allows the appearance of phases whose nature and composition are specified by the equilibrium diagram, an essential tool for understanding these transformations.

• Except in cases where the aim is to reduce foundry segregations