A software code based on SOLA-VOF algorithm is developed for numerical simulation of mold filling of semi-solid metals.The semi-solid mould filling processes of A356 and AZ91D are studied based on the Power-Law viscos...A software code based on SOLA-VOF algorithm is developed for numerical simulation of mold filling of semi-solid metals.The semi-solid mould filling processes of A356 and AZ91D are studied based on the Power-Law viscosity model and constant viscosity model,respectively.Test molds with different thicknesses and shapes were chosen to validate the software code.The simulated mould filling sequence shows a good agreement with the experimental results.The viscosity distribution is also calculated and plotted with a post-processor.The results show that the software code can offer an effective understanding for semi-solid mold filling processes.展开更多
The CdZnTe vertical Bridgman single crystal process with accelerated crucible rotation technique (ACRT) has been simulated. Effects have been investigated of the ACRT wave parameters on the solid-liquid interface conc...The CdZnTe vertical Bridgman single crystal process with accelerated crucible rotation technique (ACRT) has been simulated. Effects have been investigated of the ACRT wave parameters on the solid-liquid interface concavity and the solute segregation of the crystal. The results show that ACRT can result in the increase of both the solid-liquid interface concavity and the temperature gradient of the melt in the front of the solid-liquid interface, of which the magnitude varies from small to many times when the ACRT wave parameters change. Of the ACRT wave parameters, the increase of the crucible maximum rotation rate can hardly improve the radial solute segregation of the crystal, but the variation of the crucible acceleration time, the keep time at the maximum rotation rate, and the crucible deceleration time can affect the solute segregation of the single crystal extraordinarily. With suitable wave parameters, ACRT greatly decreases the radial solute segregation of the crystal, and even makes it disappear completely. However, it increases both the axial solute segregation and the radial one notably with bad wave parameters. An excellent single crystal could be gotten, of which a majority part is with no segregation, with ACRT-Bridgman method by adjusting both the ACRT wave parameters and the crystal growth control parameters, such as the initial temperature of the melt, the temperature gradient, and the crucible withdrawal rate, etc.展开更多
文摘A software code based on SOLA-VOF algorithm is developed for numerical simulation of mold filling of semi-solid metals.The semi-solid mould filling processes of A356 and AZ91D are studied based on the Power-Law viscosity model and constant viscosity model,respectively.Test molds with different thicknesses and shapes were chosen to validate the software code.The simulated mould filling sequence shows a good agreement with the experimental results.The viscosity distribution is also calculated and plotted with a post-processor.The results show that the software code can offer an effective understanding for semi-solid mold filling processes.
基金the National Natural Science Foundation of China (Grant Nos. 50006016 , 50372036).
文摘The CdZnTe vertical Bridgman single crystal process with accelerated crucible rotation technique (ACRT) has been simulated. Effects have been investigated of the ACRT wave parameters on the solid-liquid interface concavity and the solute segregation of the crystal. The results show that ACRT can result in the increase of both the solid-liquid interface concavity and the temperature gradient of the melt in the front of the solid-liquid interface, of which the magnitude varies from small to many times when the ACRT wave parameters change. Of the ACRT wave parameters, the increase of the crucible maximum rotation rate can hardly improve the radial solute segregation of the crystal, but the variation of the crucible acceleration time, the keep time at the maximum rotation rate, and the crucible deceleration time can affect the solute segregation of the single crystal extraordinarily. With suitable wave parameters, ACRT greatly decreases the radial solute segregation of the crystal, and even makes it disappear completely. However, it increases both the axial solute segregation and the radial one notably with bad wave parameters. An excellent single crystal could be gotten, of which a majority part is with no segregation, with ACRT-Bridgman method by adjusting both the ACRT wave parameters and the crystal growth control parameters, such as the initial temperature of the melt, the temperature gradient, and the crucible withdrawal rate, etc.
