Combined molecular dynamics and phase field simulation investigations of crystal-melt interfacial properties and dendritic solidification of highly undercooled titanium

Modeling of tip kinetics of undercooled Ti dendrites with consideration of forced flow and oxygen impurity effects

“…deviation of up to 20% only. Although is only a half of the value predicted by molecular dynamics simulation [19], it is comparable to a value of 0.30 m/s/K predicted and verified for pure Fe [23,24]. This similar magnitude is reasonable because Fe and Ti have similar melting temperatures and both crystallize into a body-centered cubic structure.…”

“…On the other hand, 0 determined is by a factor of four larger than that of Fe. This difference is understood in terms of a larger anisotropy of liquid/crystal interfacial energy [19] and higher tip velocities of Ti dendrites. There is a discrepancy between the modeling and the experiment in a low undercooling region.…”

“…The molecular dynamics simulation [19] may have overestimated . On the other hand, 0 determined is by a factor of four larger than that of Fe.…”

“…For such reasons, the values of the two fitting parameters are reasonable. * Calculated in terms of a solid/liquid interfacial energy of s/l = 0.176 J m 2 [19]. modeling provided insights into the effect of the oxygen impurity on the tip velocities of undercooled Ti dendrites.…”

“…It is unclear if the discrepancy is due to a difference in the oxygen impurity because impurity concentrations were not determined in either study. Very recently, Kavousi et al modeled tip kinetics of undercooled Ti dendrites [19]. Their molecular dynamics simulation suggested an interfacial kinetic coefficient similar to that of pure Ni, but their phase field modeling suggested tip velocities even lower than those measured by Bassler [12].…”