LAUSR

Abstract Grain boundary triple junctions (TJs) are 1-dimensional microstructural elements on their own with specific thermodynamic and kinetic properties, which are different from the connecting boundaries. Our study compares the segregation and precipitation evolution near the TJs and at grain boundaries (GBs) in an alumina-forming austenitic steel with 2.29 wt.% Mo. After annealing at 700 ℃ for 10 min, Mo segregated at the TJs and the concentration increased to ∼12 wt.%, while the concentration at GBs was ∼ 4 wt.%. After 1 h, Mo accumulated to ∼ 8 wt.% at GBs. Laves phase (Fe2Mo) formed near the TJs after 10 h. The results suggest that the TJs are the fast diffusion paths of Mo and promote the precipitation of Laves phase, which could render the fracture cracks at TJs during creep rupture.