|About this Abstract
||2021 TMS Annual Meeting & Exhibition
||Advanced High Strength Steels V
||Effects of Cold Rolling on Austenite Formation in a QLT-Treated High-Ni Martensitic Steel
||Chia-Pao Lee, Amir Farkoosh, Paul Lambert, David Seidman
|On-Site Speaker (Planned)
Low-carbon 10 wt.% Ni steels are processed through an intercritical quench-lamellarizing-tempering (QLT) treatment to form a fine dispersion of thermally-stable austenite in a martensitic matrix. Our investigations reveal that the austenite phase nucleates on crystallographic defects, such as martensite lath boundaries, grain boundaries, dislocations, and stacking faults. Thus, we hypothesize that it is possible to increase the number density and volume fraction of the retained austenite grains by increasing the existing crystallographic defects within the microstructure between the QLT treatment steps. In this study, we introduced a cold-rolling step (~10-30% plastic deformation) between the Q- and L-steps, with the purpose of increasing the dislocation density and other defects before austenite reversion. The microstructures developed after this thermomechanical treatment are studied utilizing synchrotron x-ray diffraction, atom-probe tomography, and electron backscatter diffraction analyses. Tensile and Charpy impact tests are conducted to evaluate the mechanical properties at ambient and cryogenic temperatures.
||Iron and Steel,