Dislocation Climb
The thermally assisted movement of edge dislocations perpendicular to their slip plane via vacancy diffusion. This enables plastic deformation at higher temperatures.
Dislocation climb is basically what happens in the microstructure when you relieve stresses after welding. Atoms migrate by diffusion into lattice defects and rearrange. This needs heat; without it, nothing happens. In welding, it's important because it helps you get a calm, stress-free microstructure. If you're not careful and cool the part too fast, stress remains and you risk cracks or a too-hard structure. If you do it too slowly, the structure softens. In practice, this means you have to control the cooling. The heat-affected zone should not cool abruptly, but slowly enough for atoms to settle. You do this via heat input and preheating, not by fixed temperatures.