Revealing the Effects of Pressure on the SDAS and Columnar Dendrite Growth Rate in 30Cr15Mo1N Ingot by Phase Field Method

Pressure affects the dendrite crystal growth by changing macrolevel physical phenomena and microlevel thermodynamic and transport phenomena. However, the decisive influence factors remain largely unclear. The phase field method (PFM) was conducted to unveil the underlying mechanisms of pressure on the secondary dendrite arm spacing (SDAS) and growth rate of columnar dendrite from three factors: primary dendrite arm spacing (PDAS); cooling parameters include cooling rate and temperature gradient; and physical parameters. The results demonstrate that the decrease in the PDAS and increase in cooling parameters with pressure greatly reduce SDAS. The influence proportions of cooling parameters and PDAS are about 70 and 30 pct, respectively. Meanwhile, the decrease in PDAS decreases the growth rate of columnar dendrite, while the increases in cooling parameters increase the growth rate. Influence proportions of cooling parameters and PDAS are about 180 and – 80 pct, respectively. In addition, variations of physical parameters with pressure increase SDAS and decrease the growth rate. However, these effects are small enough to be negligible. By quantitatively comparing the influence proportion of PDAS, cooling parameters, and physical parameters, it is determined that cooling parameters are the decisive factors of pressure affecting dendrite growth.