The stress-strain curves and temperature change of ultrafine-grained (UFG) austenitic steels with different grain sizes were measured during uniaxial tensile testing. The uniform stress-strain and temperature change curves are divided into three different regions depending on the hardening mechanisms. The strain-induced martensite in the UFG steels provides extra-strain hardening, large ductility and slower temperature increase. The critical stored energy for the formation of the strain-induced martensite is measured as a function of austenite grain size.
Bibliographical noteFunding Information:
This work was supported by the Agency for Defense Development under the Contract UD060017AD and by the National Core Research Center Program from MOST and KOSEF (R15-2006-022-01002-0).
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys