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Influence of Strain Rate on Tensile Properties and Dynamic Strain Aging of an Fe-24.5Mn-4Cr-0.45C Alloy

변형률 속도에 따른 Fe-24.5Mn-4Cr-0.45C 합금의 인장 특성과 동적 변형시효

  • Received : 2016.03.21
  • Accepted : 2016.04.14
  • Published : 2016.05.27

Abstract

In the present study, the tensile properties and dynamic strain aging of an Fe-24.5Mn-4Cr-0.45C alloy were investigated in terms of strain rate. During tensile testing at room temperature, all the stress-strain curves exhibited serrated plastic flows related to dynamic strain aging, regardless of the strain rate. Serration appeared right after yield stress at lower strain rates, while it was hardly observed at high strain rates. On the other hand, strain-rate sensitivity, indicating a general relationship between flow stress and strain rate at constant strain and temperature, changed from positive to negative as the strain increased. The negative strain-rate sensitivity can be explained by the Portevin Le Chatelier effect, which is associated with dynamic strain aging and is dependent on the strain rate because it is very likely that the dynamic strain aging phenomenon in high-manganese steels is involved in the interaction between moving dislocations and point-defect complexes.

Keywords

high-manganese steel;strain-rate sensitivity;dynamic strain aging;serrated plastic flow;tensile properties

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Acknowledgement

Supported by : National Research Foundation of Korea(NRF)