Solidification of the non dendrite-forming Pb-16wt%Sn alloy during spray forming

The evolution of microstructure during Spray Forming (SF) have been extensively described on the basis of the solidification process of the droplets. On the other hand, the characteristics of the alloy like temperature solidification range and the solute partitioning coefficient k0 have not been focused. This work aimed to describe the microstructure evolution of spray formed Pb-16wt%Sn alloy into a equiaxied morphology instead of a dendrite structure. The microstructure of both atomized particles and deposited material was typically comprised by equiaxial grains of Pb phase with α-Sn phase at the boundaries. It was shown that droplet solidification ruled the microstructure formation of the deposit in that the fine structure of pre-solidified droplets was extended to the deposit, despite the superheating prior to pouring and the low value of GMR of processing. It was also shown that rapidly solidified structures can be produced by SF in a same way of containerless processing.