Ahhh ok so that outer is just a pretty up ,cosmetic .
The first person to do one out of alloy welded the bracket onto the plate but I notice your castings are better than mine , stress cracks mainly come from overheating during welding although ally can be annealed to reduce any stress .
As you've said though yours is cosmetic and your welds are good so no excess heat , if the rest of your welds are like that no you shouldn't have any problems .
Heard of a process in aircraft aly ,after welding the area gets a quick hit with a carbonising acetylene flame then gently heated till the carbon disappears.