Comparing the solidification characteristics of supercooling directional solidification(SDS) with constrained directional solidification(D. S. ) and considering the inheritance of supercooled melt, the supercooling di...Comparing the solidification characteristics of supercooling directional solidification(SDS) with constrained directional solidification(D. S. ) and considering the inheritance of supercooled melt, the supercooling directional solidification technique with the combination of melt supercooing and traditional directional solidification was proposed. An exploring study on SDS techniques was also conducted by using appropriate selfmade facilities and the deep supercooling of Cu-5. O % Ni alloy and its directional solidification were implemented. The experimental results show that: 1 ) the solidification microstructure produced by SDS are nearly the same as that by LMC technique, its primary arm spacing is around 30 Um in average and the secondary sidebranch is considerably degenerated; 2) the primary arm trunk of microstructure appears straight and fine, and the average deviation of crystal growth orientation from the axial line is about 5. 8; 3) a mathematical model describing the relationship between melt supercooling by SDS and the solidification rate, namely T-T model,was established, by which the microstructure evolution in SDS can be explained.展开更多
This paper is a continuation of Ref. [1]. It employs frist-order accurateTaylor-Galerkin-based finite element approach for casting solidification. Theapproach is based on expressing the finite-difference approximation...This paper is a continuation of Ref. [1]. It employs frist-order accurateTaylor-Galerkin-based finite element approach for casting solidification. Theapproach is based on expressing the finite-difference approximation of thetransient time derivative of temperature, while the expressions of the governingequations are discretized in space via the classical Galerkin scheme using finite-element formulations. The detailed technique is reported in this study. Severalcasting solidification examples are solved to demonstrate the excellentagreements in comparison with the results obtained by using the control volumemethod, and to show the availability of combination of the finite elementmethod and the finite difference method in multi-dimensional modeling ofcasting solidification.展开更多
文摘Comparing the solidification characteristics of supercooling directional solidification(SDS) with constrained directional solidification(D. S. ) and considering the inheritance of supercooled melt, the supercooling directional solidification technique with the combination of melt supercooing and traditional directional solidification was proposed. An exploring study on SDS techniques was also conducted by using appropriate selfmade facilities and the deep supercooling of Cu-5. O % Ni alloy and its directional solidification were implemented. The experimental results show that: 1 ) the solidification microstructure produced by SDS are nearly the same as that by LMC technique, its primary arm spacing is around 30 Um in average and the secondary sidebranch is considerably degenerated; 2) the primary arm trunk of microstructure appears straight and fine, and the average deviation of crystal growth orientation from the axial line is about 5. 8; 3) a mathematical model describing the relationship between melt supercooling by SDS and the solidification rate, namely T-T model,was established, by which the microstructure evolution in SDS can be explained.
文摘This paper is a continuation of Ref. [1]. It employs frist-order accurateTaylor-Galerkin-based finite element approach for casting solidification. Theapproach is based on expressing the finite-difference approximation of thetransient time derivative of temperature, while the expressions of the governingequations are discretized in space via the classical Galerkin scheme using finite-element formulations. The detailed technique is reported in this study. Severalcasting solidification examples are solved to demonstrate the excellentagreements in comparison with the results obtained by using the control volumemethod, and to show the availability of combination of the finite elementmethod and the finite difference method in multi-dimensional modeling ofcasting solidification.
