Structure of continuously cast Ni-based superalloy Inconel 713C

In this work, we characterised the structure of continuously cast Ni-based superalloy IN 713C (circle divide 10 mm, water cooled Cu-Be mould, argon atmosphere) using several microstructural characterization techniques (LM, SEM. TEM, EDS, XRD). The structure consisted of columnar dendritic gamma -grains with apparently fully coherent and rather uniformly distributed gamma' precipitates (size similar to 50 nm). primary MC carbide and MC/gamma eutectic, The eutectic MC carbide contained a considerable amount of Cr: (Nb0.4Mo0.25Ti0.18Cr0.16)C resulting in a decrease in the MC lattice constant from 0.441 to 0.435 run. Due to higher cooling rates at continuous casting the microstructural constituents were much finer than in the as-received and DTA samples. In addition, the continuously cast specimens did not contain the gamma/gamma' eutectic and some minor phases despite stronger segregation of solute elements. The partition coefficients of solute elements Ti, Mo, Nb, Al, Cr, Fe and Ni in the continuously cast IN 713C were 0.55, 0.82, 0.46, 0.99, 0.96, 1.02 and 1.03, respectively. (C) 2001 Elsevier Science B.V. All rights reserved.