Heat treatment by annealing can be used to restore the ductility of a cold worked steel. During annealing, the material is held at an elevated temperature for some time and the cold worked material will undergo a sequence of recovery, recrystallization and grain growth, which eventually reduces the hardness and improves ductility. Annealing is, however, usually performed as a bulk process on entire components, for example by placing them in a furnace. Significantly more precision can be achieved if a laser beam is used as the heat source. The accuracy of this method is high enough to allow annealing of regions of millimeter size and in arbitrary patterns. The material’s microstructure can be modified locally, making laser annealing a useful tool in manufacturing of functionally graded steels.
Project and collaborators
The project combines laser annealing experiments with level set-based simulations of the microstructure evolution and is a collaboration with researchers at École Nationale Supérieure d’Arts et Métiers in Paris.