Tantalum and niobium based Z-phase in a Z-phase strengthened 12% Cr steel
Paper in proceedings, 2016

Higher steam temperature in steam power plants increases their thermal efficiency. Thus there is a strong demand for new materials with better creep and corrosion resistance at higher temperatures, while retaining the thermal flexibility of martensitic steels. Z-phase strengthened 12% Cr steels have been developed to meet the 923 K (650 degrees C) challenge in these power plants. Ta, Nb, or V forms Z-phase together with Cr and N. A new trial steel was produced based on combining Ta and Nb to form Z-phase. It was shown that Z-phase was formed with a composition corresponding to Crl+x(Nb,Ta)(l+x)N. The Nb/Ta ratio in Z-phase precipitates was higher than that in MX precipitates. Z-phase precipitates based on Ta and Nb were coarser than precipitates in a similar trial steel based on Ta alone.

Martensitic steels

APT

TEM

Z-phase

SEM

Author

Masoud Rashidi

Chalmers, Physics, Materials Microstructure

ROBERT LAWITZKI

Chalmers, Physics, Materials Microstructure

Hans-Olof Andrén

Chalmers, Physics, Materials Microstructure

Fang Liu

Chalmers, Physics, Materials Microstructure

Advances in Materials Technology for Fossil Power Plants - Proceedings from the 8th International Conference on Advances in Materials Technology for Fossil Power Plants; Albufeira, Portugal; 11-14 October 2016

1058-1066

Subject Categories

Metallurgy and Metallic Materials

More information

Latest update

10/16/2018