The dendrite structure, which is formed during centrifugal casting process, plays an important role in the fracture behavior of 20Cr32Ni1Nb alloy. The large primary carbide facilitates the crack nucleation and propagation along the dendrite interface during high temperature deformation. The secondary NbC precipitates near the dendrite interface during aging at 1120 degrees C, while the major precipitates change to secondary Cr23C6 when aging at lower temperature. These secondary carbides effectively strengthen the dendrite interface, which is probably due to inhibiting the crack propagation and decreasing the stress concentration. However, the benefit of the secondary carbide reduce when the precipitation free zone form aging at high temperature. Increasing C content enhances the precipitation tendency of Cr23C6, and facilitates the coalescing of the carbide at elevated temperature. As a result, the cracks can easily nucleate at the interface between NbC and Cr23C6, and then propagate along the large chromium carbide during deformation. However, the small chromium carbide precipitates form at lower aging temperature, and thus strengthens the alloy effectively. (C) 2016 Elsevier B.V. All rights reserved.