publications

2023

1. 

   On the occurrence of buoyancy-induced oscillatory growth instability in directional solidification of alloys

   Josep Maria Barbera, Thomas Isensee, and Damien Tourret

   IOP Conference Series: Materials Science and Engineering, May 2023

   Abs Bib Code

   Recent solidification experiments identified an oscillatory growth instability during directional solidification of Ni-based superalloy CMSX4 under a given range of cooling rates. From a modeling perspective, the quantitative simulation of dendritic growth under convective conditions remains challenging, due to the multiple length scales involved. Using the dendritic needle network (DNN) model, coupled with an efficient Navier-Stokes solver, we reproduced the buoyancy-induced growth oscillations observed in CMSX4 directional solidification. These previous results have shown that, for a given alloy and temperature gradient, oscillations occur in a narrow range of cooling rates (or pulling velocity, V p ) and that the selected primary dendrite arm spacing (Λ) plays a crucial role in the activation of the flow leading to oscillations. Here, we show that the oscillatory behavior may be generalized to other binary alloys within an appropriate range of (V p ,Λ) by reproducing it for an Al-4at.%Cu alloy. We perform a mapping of oscillatory states as a function of V p and Λ, and identify the regions of occurrence of different behaviors (e.g., sustained or damped oscillations) and their effect on the oscillation characteristics. Our results suggest a minimum of V p for the occurrence of oscillations and confirm the correlation between the oscillation type (namely: damped, sustained, or noisy) with the ratio of average fluid velocity over V p . We describe the different observed growth regimes and highlight similarities and contrasts with our previous results for a CMSX4 alloy.

   @article{barbera2023occurrence,
     doi = {10.1088/1757-899X/1281/1/012050},
     url = {https://dx.doi.org/10.1088/1757-899X/1281/1/012050},
     year = {2023},
     month = may,
     publisher = {IOP Publishing},
     volume = {1281},
     number = {1},
     pages = {012050},
     author = {Barbera, Josep Maria and Isensee, Thomas and Tourret, Damien},
     title = {On the occurrence of buoyancy-induced oscillatory growth instability in directional solidification of alloys},
     journal = {IOP Conference Series: Materials Science and Engineering},
   }