| The objective of this study is to explore the instabilities that occur in the unidirectional solidification of pure metals due to the thermal distortion caused by imperfections on the contact surfaces between the mold and casting. In addition to the previous studies, temperature dependent material properties and a visco-elastic constitutive model are introduced to obtain a better approximation to the behaviour of a realistic material. To demonstrate the effect of using more realistic approximations, unidirectional solidification of a pure aluminum metal is considered.; The major findings reported here include that temperature dependent material properties for pure aluminium increase the instability of the contact pressure at the mold/casting interface during the solidification process. It is also demonstrated that the contact pressure is very sensitive to the variation of Young's Modulus with temperature. Results obtained for the contact pressure with a visco-elastic constitutive model show that visco-elastic stresses have a stabilizing effect on the contact pressure at the mold/casting interface. |
