The research and development of Nb-containing superalloy in China

Niobium is an important strengthening element in Fe-base, Ni-Fe-base and Ni-base superalloys. China has paid special attention on Nb in development and improvement of superalloys. An iron-base superalloy GH 4871, a modification of A-286 with 0.5~0.6%Nb, can be used as blade or disk material at 600~650DGC. A systematic research and development has been conducted in China for improving the temperature capability of Nb-containing (5~5.5%Nb) Ni-Fe-base superalloy Inconel 718 (Chinese designation GH4169) from 650 to 700DGC. A Ni-base superalloy GH4133 contains 1.5%Nb with 2.5~3.0%Ti and 0.7~1.2%Al, it has been got wide application at 700DGC for variety of disks in Chinese jet-engines. For economical reason the replacement of Nb for Ta is also discussed from viewpoint of strengthening in B1900 Ni-base superalloy. (AU)