Abstract :
Austenitic Fe–Cr–Mn stainless steels interstitially
alloyed with nitrogen have received considerable
interest lately, due to their many property improvements
over conventional Fe–Cr–Ni alloys. The addition of
nitrogen to Fe–Cr–Mn stabilizes the fcc structure and
increases the carbon solubility. The benefits of increased
interstitial nitrogen and carbon content include: enhanced
strength, hardness, and wear resistance. This study examines
the effect of carbon, silicon, molybdenum, and nickel
additions on the phase stability and tensile behavior of
nitrogen-containing Fe–Cr–Mn alloys. Nitrogen and carbon
concentrations exceeding 2.0 wt.% were added to the base
Fe–18Cr–18Mn composition without the formation of
nitride or carbide precipitates. Minor additions of molybdenum,
silicon, and nickel did not affect nitrogen
interstitial solubility, but did reduce carbon solubility
resulting in the formation of M23C6 (M=Cr, Fe, Mo) carbides.
Increasing the interstitial content increases the lattice
distortion strain, which is directly correlated with an
increase in yield stress.
