Four types of high Mn TWIP(Twinning Induced Plasticity) steels were fabricated by varying the Mn and Al content, and the tensile properties were measured at various strain rates and temperatures. An examination of the tensile properties at room temperature revealed an increase in strength with increasing strain rate because mobile dislocations interacted rapidly with the dislocations in localized regions, whereas elongation and the number of serrations decreased. The strength decreased with increasing temperature, whereas the elongation increased. A martensitic transformation occurred in the 18Mn, 22Mn and 18Mn1.6Al steels tested at −196 oC due to a decrease in the stacking fault energies with decreasing temperature. An examination of the tensile properties at −196 oC showed that the strength of the non-Al added high Mn TWIP steels was high, whereas the elongation was low because of the martensitic transformation and brittle fracture mode. Although a martensitic transformation did not occur in the 18Mn1.9Al steel, the strength increased with decreasing temperature because many twins formed in the early stages of the tensile test and interacted rapidly with the dislocations.

1. 서 론
 2. 실험 방법
 3. 결 과
  3.1 변형률 속도 10−3 sec−1과 10−1 sec−1에서의 인장특성
  3.2 200 oC와 −196 oC에서의 인장 특성
 4. 고 찰
  4.1 인장 시험 후 미세조직의 변화
  4.2 인장 특성에 미치는 변형률 속도의 영향
  4.3 인장 특성에 미치는 온도의 영향
 5. 결 론
 Acknowledgement
 References

• 이정훈(포항공과대학교 항공재료연구센터) | Junghoon Lee (Center for Advanced Aerospace Materials Pohang University of Science and Technology)
• 이성학(포항공과대학교 항공재료연구센터) | Sunghak Lee (Center for Advanced Aerospace Materials Pohang University of Science and Technology)
• 신상용(울산대학교 첨단소재공학부) | Sang Yong Shin (School of Materials Science and Engineering University of Ulsan) Corresponding author