An Analysis of Solidification Experiments With a Ti-46Al-8Nb Alloy Under Centrifugal Conditions: Modelling of Flow–Solidification Interaction and Grain Structure Evolution Using a Cellular Automaton With Finite Volume Method

Solidification experiments with alloy Ti-46Al-8Nb were conducted in ESA’s large diameter centrifuge aiming at investigating the columnar-to-equiaxed transition (CET) under hypergravity conditions. Experiments were performed such that the resultant acceleration is opposite to the direction of solidification. Under these conditions, CET is promoted and occurs earlier when increasing the angular velocity $$\omega $$ , mainly due to the convection pattern and the related thermosolutal fields. Numerical modelling was conducted for studying the effect of flow–solidification interaction on the evolution of the grain structure. It is achieved by coupling a cellular automaton with conservation equations governing the solidification and thermosolutal convection. The simulated grain structures are compared to the experimental results. The CET events in experiments under resultant acceleration forces of 5, 15, and 18 g are explained by the simulation results. Emphasis is placed on analyzing how the undercooled region and competition between columnar and equiaxed grain growth are affected by the thermosolutal convection under different centrifugal conditions.