Microstructure stability of ferritic-martensitic, austenitic and fully ferritic steels under fluctuating loading conditions

Abstract:

A new type of Laves phase strengthened, high chromium, High performance Ferritic (HiperFer) steel was benchmarked in terms of creep, cyclic creep, thermomechanical fatigue and microstructure stability against the ferritic-martensitic (FM) grades P91 and T92 and the austenitic grade AISI310. The HiperFer steel exhibited supreme creep and cyclic creep performance in short-term tests and promises high potential in the mid and long-term. It reached the longest thermomechanical fatigue lifetimes, while the FM and austenitic grades suffered premature failure. With the help of electron back backscatter diffraction recrystallization of the subgrain structure was identified to be the reason for failure under thermomechanical fatigue loading conditions in case of the FM steels. Improved microstructural stabilization by precipitation of an immense number of sub-micron (Fe, Si, Cr) 2 (Nb, W) Laves phase particles prevented recrystallization in case of the HiperFer trial steel.

Año de publicación:

2015

Keywords:

Fuente:

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