Isothermal annealing is a process where a material is heated to a specific temperature and held at that temperature for a required period, before being cooled at a controlled rate for the formation of more stable microstructures.

The cooling rate is also important as it influences the final microstructure and mechanical properties of the material. Iso-thermal annealing can cause the recrystallization of strained material, which reduces internal stresses, restores ductility, and results in a more uniform microstructure.