Interaction Between Elements Nb and Mo During Precipitation in Microalloyed Austenite

Thermo-simulation test and transmission electron microscopy (TEM) have been used to investigate the interaction between the microalloying elements Nb and Mo within the precipitates during relaxation after austenite deformation of C-Ti-Mo steel and C-Nb-Mo steel. The experimental results demonstrated that the austenitic structure was preserved both in C-Ti-Mo steel and C-Nb-Mo steel even if they were relaxed for 1000 s after deformation at 850 degrees C. The strain-induced precipitate occurs in two kinds of steel. Through the energy spectrum analysis, it was found that the precipitates were Ti(C, N) and Mo-bearing Nb(C, N) respectively and there exists a strong affinity of Mo for Nb with in the precipitates. Mo atoms would enter the lattice of Nb(C, N) particles probably after Nb(C, N) formation.