Unidirectionally solidified cast article and method of making

摘要

A cast superalloy article (14) having a unidirectional crystal structure that is substantially defect free with primary dendrite arm spacing greater than 150 mu m is provided. The unidirectional crystalline microstructure comprises a longitudinal columnar structure (7,8,9) aligned parallel with the direction of solidification where said columnar structure is a single crystal or polycrystals or mixtures thereof.