Strengthening behavior of Fe–Cr–Ni–Al–(Ti) maraging steels

In the present work a Ti-free and Ti-containing stainless maraging steel of type PH13-8 Mo were investigated with respect to their mechanical properties. Particular attention was given to the stress–strain behavior during tensile tests in correlation to the developed precipitates and austenite at differently aged conditions. Both alloys show a strong increase in strength from the very beginning of aging with the typical stress–strain behavior of maraging steels, whereas the Ti-containing alloy suffers from severe intergranular embrittlement at short aging times. Embrittlement of the Ti-containing steel grade is attributed to the significantly higher volume fraction of precipitates in the early stages of aging when compared to the Ti-free steel grade. Overaging leads to distinct work hardening in the Ti-containing alloy, which is caused by the evolution of the precipitates and the formation of reverted austenite.