> Scandium makes those grains smaller, among other things, which allows them to fit closer together for a denser, stronger overall structure. This is not how g

> Scandium makes those grains smaller, among other things, which allows them to fit closer together for a denser, stronger overall structure. This is not how grain size strengthening works. With smaller grains, there are more grain boundaries. These boundaries present an obstacle to the movement of dislocations, increasing the resistance to deformation. Density is not affected by grain size, larger grains do not have any gaps between them.