Aluminum-Scandium Grain Refinement Effect

Scandium is added to aluminum alloys to keep the grain fine. The stuff forms tiny, stable particles that slow down grain growth. When welding, that means you get a finer structure and thus better mechanical properties, especially when it gets hot. If you don't get the alloy right or don't control the heat input, the structure can locally coarsen. Then you have weak points and, in the worst case, cracks. So watch out for clean melt guidance and avoid unnecessary overheating. With the right amount of additive and clean work, you can handle that well.