Hi! I am Daniel, a resistance welding technician of a Spanish Technological Center and I am carrying on one project related with weldability of 5000 and 6000 series of wrought aluminium alloys.
I have the following problem in the HAZ of spot welds:
Sometimes, apparent liquation cracks appear at liquated grain boundaries in this zone. Really, they are not cracks and seem to be intrusions of material of spot welds.
Is this phenomenom influenced by solidification shrinkage and thermal contraction?
Do you think that static and dynamic properties will be minimized?

Thank you in advance for your help.