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Effect of vanadium (V) on the solidification and homogenization behaviors in Inconel 718 alloy is investigated. V is observed to evenly distribute in dendritic and interdendritic zones, and slightly increase niobium (Nb) and molybdenum (Mo) segregation coefficients. However, Laves phase volume fraction reduces from 2.3 to 0.4%, indicating that V may effectively prevent the precipitation of Laves phase. Homogenization results show that diffusion coefficient of Nb is much higher in the V-containing alloy, and it takes fewer hours to remove Laves phase, which suggest that microalloying of V can be very helpful in ingots homogenization annealing of Inconel 718 alloy in industry production.

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Ni-based superalloys have attracted much attention due to their good resistance to high-temperature and -pressure environments. Compared with the traditional 718 Ni-based superalloy, 945A Ni-based superalloy with a lower Ni content showed better performance in terms of precipitated hardening and corrosion resistance. In this study, the aging behavior and the evolution of mechanical properties of the wrought 945A Ni-based superalloy were investigated. Microstructures were analyzed by scanning electron microscopy (SEM), bright field transmission electron microscopy (TEM), high-resolution TEM and high-angle annular dark field scanning TEM. Mechanical properties were measured by tensile and compressive tests. The results illustrated that the compressive yield stress was significantly improved by increasing aging time from 229 to 809 MPa. The increase was greater than 220%. This improvement was mainly attributed to the precipitates of the  γ′ phase and carbides during the aging treatment. The residual dislocations generated by the plastic processes stimulated the formation of these precipitates. The precipitation behavior and the strengthening mechanism are discussed in detail.