Meaning of "improved" when used as an adjective to compare between two different things?

I encountered this sentence today while translating form english:

These alloys lack the crystallinity of conventional engineering alloys, and some of their properties —such as higher yield stress and elastic strain limit— are greatly improved relative to their crystalline counterparts.

What would be the meaning of improved here? Does it simply mean better? Which means that their properties are much better than that of the crystalline ones?
Or the comparison here is between the level of improvement of the properties of the two types of alloys?