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http://dx.doi.org/10.5228/KSTP.2011.20.4.309

Effect of Microstructure on Dynamic Tensile Characteristics of SPRC440 Sheet  

Lee, S.H. (부산대학교 재료공학과)
Rhyim, Y.M. (재료평가연구그룹)
Lee, J.H. (한국기계연구원 부설 재료연구소)
Kim, I.B. (한국기계연구원 부설 재료연구소)
Kim, Y.D. (한국기계연구원 부설 재료연구소)
Publication Information
Transactions of Materials Processing / v.20, no.4, 2011 , pp. 309-315 More about this Journal
Abstract
The behavior of metallic materials at high strain rates shows different characteristics from those in quasi-static deformation. Therefore, the strain rate should be considered when simulating crash events. The objective of this paper is to evaluate the dynamic tensile characteristics of SPRC440 as a function of the volume fraction of phases. As-received SPRC440 is composed of ferrite and pearlite phases. However, ferrite and martensite phases were observed after heat treatment at $730^{\circ}C$ and $780^{\circ}C$ for 5 minutes, as expected by calculations based on the curves from dilatometry tests. High cross-head speed tensile tests were performed to acquire strain-stress curves at various strain rates ranging from 0.001 to $300\;s^{-1}$, which are typical in real vehicle crashes. It was observed that the flow stress increases with the strain rate and this trend was more pronounced in the as-received specimens consisting of ferrite and pearlite phases. It is speculated that the dislocation density in each phase has an influence on the strain rate sensitivity.
Keywords
Dynamic Tensile Test; Strain Rate Sensitivity; Flow Stress; Dislocation Density; Microstructure;
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Times Cited By KSCI : 1  (Citation Analysis)
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