The effect of C, Mn, and Al additions on the tensile and Charpy impact properties of austenitic high-manganese steels for cryogenic applications is investigated in terms of the deformation mechanism dependent on stacking fault energy and austenite stability. The addition of the alloying elements usually increases the stacking fault energy, which is calculated using a modified thermodynamic model. Although the yield strength of austenitic high-manganese steels is increased by the addition of the alloying elements, the tensile strength is significantly affected by the deformation mechanism associated with stacking fault energy because of grain size refinement caused by deformation twinning and mobile dislocations generated during deformation-induced martensite transformation. None of the austenitic high-manganese steels exhibit clear ductile-brittle transition behavior, but their absorbed energy gradually decreases with lowering test temperature, regardless of the alloying elements. However, the combined addition of Mn and Al to the austenitic high-manganese steels suppresses the decrease in absorbed energy with a decreasing temperature by enhancing austenite stability.

Abstracts
 1. 서 론
 2. 실험 방법
 3. 실험 결과 및 고찰
  3.1 적층결함 에너지와 미세조직
  3.2 인장 특성
  3.3 충격 특성
 4. 결 론
 References

• 이승완(서울과학기술대학교 신소재공학과) | Seung-Wan Lee (Department of Materials Science and Engineering, Seoul National University of Science and Technology)
• 황병철(서울과학기술대학교 신소재공학과) | Byoungchul Hwang (Department of Materials Science and Engineering, Seoul National University of Science and Technology) Corresponding author