On the Effect of Nb on the Microstructure and Properties of Next Generation Polycrystalline Powder Metallurgy Ni-Based Superalloys

Abstract The effect of Nb on the properties and microstructure of two novel powder metallurgy (P/M) Ni-based superalloys was evaluated, and the results critically compared with the Rolls-Royce alloy RR1000. The Nb-containing alloy was found to exhibit improved tensile and creep properties as well as superior oxidation resistance compared with both RR1000 and the Nb-free variant tested. The beneficial effect of Nb on the tensile and creep properties was due to the microstructures obtained following the post-solution heat treatments, which led to a higher γ′ volume fraction and a finer tertiary γ′ distribution. In addition, an increase in the anti-phase-boundary energy of the γ′ phase is also expected with the addition of Nb, further contributing to the strength of the material. However, these modifications in the γ′ distribution detrimentally affect the dwell fatigue crack-growth behavior of the material, although this behavior can be improved through modified heat treatments. The oxidation resistance of the Nb-containing alloy was also enhanced as Nb is believed to accelerate the formation of a defect-free Cr2O3 scale. Overall, both developmental alloys, with and without the addition of Nb, were found to exhibit superior properties than RR1000.This work was supported by the Rolls-Royce/EPSRC Strategic Partnership under EP/H022309/1, EP/H500375/1 and EP/ M005607/1

Elasticity, acoustic loss, and γ′ dissolution in superalloys from resonant ultrasound spectroscopy

The high temperature acoustic loss and elastic moduli of the Ni-based superalloys RR1000, Waspaloy and Allvac® 718Plus™ were investigated using resonant ultrasound spectroscopy. An exponential increase in acoustic loss was seen in all alloys, which was viscoelastic in character with an activation energy of ~ 200-400 kJ.mol-1, similar to that of the self-diffusion of Ni. The magnitude of the loss was found to be proportional to d-0.85, where d is the grain size. Deviations from the high temperature background were seen in the alloys Waspaloy, and 718Plus around their γ′ solvus temperatures, attributed to increased diffusion during γ′ dissolution. It is suggested that acoustic loss in Ni-based alloys may be used as a means of determining the γ′ solvus temperatures.The authors would like to acknowledge the EPSRC / Rolls-Royce Strategic Partnership for funding EP/H022309/1 and EP/M005607/1). RUS facilities were established in Cambridge through grants from the Natural Environment Research Council of Great Britain (NE/B505738/1 and NE/F017081/1)

Research data supporting "The effect of heat treatment on precipitation in the Cu-Ni-Al alloy Hiduron130"

The data includes the raw files for all data reported in publication "The effect of heat treatment on precipitation in the Cu-Ni-Al alloy Hiduron 130". SEM, TEM, EDX, XRD xy file, DSC text files and hardness data is all included

Accompanying data for "On the effect of Nb on the microstructure and properties of next generation polycrystalline powder metallurgy Ni-based superalloys"

The data has been labelled with the same designations as used in the corresponding paper. Raw data is provided from differential scanning calorimetry and scanning electron microscopy following the various heat treatments and oxidation analyses. In addition, data is provided from the tensile, creep and dwell tests performed and the outcomes of the mechanical property modelling are also given.This work was supported by the Rolls-Royce/EPSRC Strategic Partnership under EP/H022309/1, EP/H500375/1 and EP/ M005607/1

European Nuclear Thermodynamic Database Validated and Applicable in Severe Accident Codes: ENTHALPY Project

International audienc

European Nuclear Thermodynamic Database Validated and Applicable in Severe Accident Codes: ENTHALPY Project

International audienc