1202.4135 (L. Yuan et al.)

Nanoscale austenite reversion through partitioning, segregation, and
kinetic freezing: Example of a ductile 2 GPa Fe-Cr-C steel    [PDF]

L. Yuan, D. Ponge, J. Wittig, P. Choi, J. A. Jiménez, D. Raabe

Austenite reversion during tempering of a Fe-13.6Cr-0.44C (wt.%) martensite
results in an ultrahigh strength ferritic stainless steel with excellent
ductility. The austenite reversion mechanism is coupled to the kinetic freezing
of carbon during low-temperature partitioning at the interfaces between
martensite and retained austenite and to carbon segregation at
martensite-martensite grain boundaries. An advantage of austenite reversion is
its scalability, i.e., changing tempering time and temperature tailors the
desired strength-ductility profiles (e.g. tempering at 400{\deg}C for 1 min.
produces a 2 GPa ultimate tensile strength (UTS) and 14% elongation while 30
min. at 400{\deg}C results in a UTS of ~ 1.75 GPa with an elongation of 23%).
The austenite reversion process, carbide precipitation, and carbon segregation
have been characterized by XRD, EBSD, TEM, and atom probe tomography (APT) in
order to develop the structure-property relationships that control the
material's strength and ductility.

View original: http://arxiv.org/abs/1202.4135