3D Modeling of Dendritic Grain Structures in Turbine Blade Investment Cast Parts

Abstract

A three-dimensional (3D) Cellular Automaton -Finite Element (CAFE) model is presented for the modeling of dendritic solidification grain structures. It is applied to the prediction of the grain structure formed in investment cast parts, demonstrating its ability to reproduce the growth competition occurring among columnar grains in a pig-tail grain selector, the extension of a grain in an undercooled region of liquid (re-entrant corner), as well as polycrystalline growth in Directionally Solidified (DS) turbine blades. This 3D CAFE model is a very valuable metallography tool for the design of investment cast parts. In particular, it allows to study grain defects such as spurious nucleation of stray crystals in undercooled regions, grain selection and grain texture evolutions.