Dendrite growth and microsegregation during directional solidification: ananalytical model and experimental studies on the superalloy CMSX-4

An analytical 2-dimensional model taking account of the anisotropy of cryst al growth is proposed to describe dendrite growth during directional solidi fication, Within a unit cell, a shape function of the dendrite is defined. This depends on the solidification condition, the local fraction solid and crystallographic orientation. As a result, the advance of the liquid-solid interface and the concentration distribution in a cross-section of a dendri te can be predicted two-dimensionally. The paper introduces a method of app lying the proposed model, initially developed for binary alloys, to multico mponent systems, Calculation was completed for a directionally solidified N i-base superalloy CMSX-4, allowing prediction of microstructural evolution and microsegregation behaviour. The calculation results are compared with e xperimental measurements.