Numerical Modelling of Gas Atomised Metal Droplets

Abstract: The ability to predict nucleation and solidification behaviour is essential for producing high-quality  metal  powders. The  droplet  cooling  of  complex multi-component  alloy systems has not been accurately  studied  by  any models  to  date. In  this  study,  a computational model to simulate the nucleation and cooling of metal melt droplets in a  gas  atomisation  process  is formulated.  Even  the  nucleation  and  cooling  events  of complex multicomponent alloy systems can be predicted using the model. The model is made  stochastic  by  comparing  the  probability  of  nucleation  to  a  random numeric value to determine the occurrence of nucleation. Thermo-Calc Software version 2021ais  utilized  in  the  model  to  collect  live  thermodynamic  data for  each  time step.  The nucleation model predicts a reduction in nucleation temperature of roughly 1 K for a droplet  size  reduction  of  10  μm. The model predicts  an  undercooling  of  35  kelvin before  nucleation  for the alloy compositionFe-0.4%C-5%Ni-0.7%Si.All  the  results except  the  ones  from the recalescence  stage are  consistent with the conventional metallurgical  theory. Results confirm  that  the  model  is  sensitive  to  droplet  size,  gas properties,  and  composition. The  results  from  this  study  can  help  in predicting nucleation more accurately allowing the industry to anticipate powder qualities ahead of  time,  resulting  in  better  resource  efficiency. This research might  open  new possibilities  for  implementing  stochastic  techniques  to study  nucleation  and  droplet solidification.