Effect of carbon content on solidification behavior of a Mo- and Al-rich nickel-based single-crystal superalloy

Release time:2026-02-05 Hits:

Journal:Materials & Design

Key Words:Optimizing carbon content is critical for the design of Ni-based single-crystal superalloys, particularly for high-temperature applications. This study systematically investigated the influence of carbon on the solidification behavior and phase evolution of a Mo- and Al-rich Ni-based single-crystal superalloy. Increasing carbon content lowered the solidus temperature and widened the mushy zone, which is associated with the precipitation of low-melting-point carbides during the terminal stage of solidification. At 56 ppm carbon, no carbides were observed and the interdendritic regions contained the σ-NiMoRe phase with a tetragonal structure. At 180 ppm carbon, σ-NiMoRe and blocky primary M6C carbides coexisted adjacent to the large primary blocky γ′ phase, separated by distinct boundaries. At 270 ppm carbon, script-like, Mo- and Ta-enriched M6C carbides with a cubic (fcc-type) structure became the dominant interdendritic constituent; concurrently, elemental segregation became more pronounced. Increasing carbon content also increased the secondary dendrite arm spacing (SDAS) and reduced both the liquid viscosity (μ) and solidification shrinkage coefficient (β). These effects contributed to significant porosity reduction by decreasing the shrinkage pressure drop. Overall, controlled carbon addition optimizes solidification behavior and phase stability, providing practical guidance for alloy design and solidification control in Mo- and Al-rich Ni-based single-crystal superalloys.

Indexed by:Journal paper

Correspondence Author:haigen zhao

Translation or Not:no

Date of Publication:2026-02-05

Included Journals:SCI