u/DikkeTosti1998

I'm pouring ingots of 99.5% tin with 0.5% bismuth in order to create a tin alloy that does not form tin pest, while maintaining a high tin concentration.

Why are different crystals growing in different regions? And does this affect the bismuth concentrations throughout the ingot?

I suspect cooling rate to be a factor, where the center top of the ingot cools slowest as it can only dissipate the heat by convection, but i would love to understand better what is happening in a metallurgical point of view.

Before pouring, I manually stir the molten metals to aid in the bismuth dissolving.

Thanks in advance!