A study of the heat parameters during bidirectional solidification

The temperature field and heat parameters are important in controlling metal liquid crystallinity in unidirectional and bidirectional solidification. The temperature field can be divided into three cases: a liquid temperature field; solid temperature field; and a temperature field on the solid-liquid (S–L) interface. Heat parameters can be divided into two cases: technical heat parameters; and solidification heat parameters. The temperature field on the S–L interface and solidification heat parameters are the most important for the structures and properties of materials. The temperature field on the S–L interface is determined by the alloy system, and solidification heat parameters are related to the temperature ield of the environment and technical heat parameters. The temperature ield on the S–L interface is closely related to the solidiication heat parameters.A theoretical model describing precisely the temperature field on the S–L interface during bidirectional solidification was proposed. A series of heat parameters, including temperature gradients G, solidification rate R, cooling velocity V and characteristic temperature Tc have been derived from this model. A superalloy has been chosen as the experimental object in order to verify the theoretical model. The theoretical calculations are found to be in agreement with the experimental results.