Aluminum and thin chromoly are so hard that they need a radius at the bend rather than a sharp knife’s edge or they could crack and split. Some breaks will have more of a radius machined into the clamping jaws. Alternatively you could have some small round bar or tube welded to some plate that would go between the clamping jaw and the material to be bent to increase the minimum bend radius. Here we tried to do everything wrong. We made a very sharp bend with the grain (instead of against it) to see if we could get the aluminum to crack, but not much of a crack is showing.