[New type of M/sub 23/C/sub 6/ carbide precipitation in an austenitic stainless steel containing niobium]

It was observed that a new type of thin plate precipitation of M /sub 23/C/sub 6/ carbide occurs in the austenitic stainless steel, 16 Cr-16 Ni-0.8 Nb. The precipitate is formed in the region near the non-dissolved NbC particle by ageing of long duration at 800 degrees C. It seems that the NbC particle is decomposed during the precipitation of M/sub 23/C/sub 6/ carbides and that carbon atoms liberated by this decomposition induce the formation of the M/sub 23/C/sub 6 / thin plate. This plate is constituted of a large {110} plane whose edges are limited by {111} planes.Francai