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Metallurgical Transactions A

, Volume 9, Issue 5, pp 713–721 | Cite as

Transformation behavior of TRIP steels

  • G. B. Olson
  • M. Azrin
Transformations

Abstract

True-stress (σ), true-strain (ε) and volume fraction martensite(f) were measured during both uniform and localized flow as a function of temperature on TRIP steels in both the solution-treated and warm-rolled conditions. The transformation curves(f vs ε) of materials in both conditions have a sigmoidal shape at temperatures above Ms σ (maximum temperature at which transformation is induced by elastic stress) but approach initially linear behavior at temperatures below Ms σ where the flow is controlled by transformation plasticity. The martensite which forms spontaneously on cooling or by stress-assisted transformation below Ms σ exhibits a plate morphology. Additional martensite units produced by strain-induced nucleation at shear-band intersections become important above Ms σ. Comparison of σ-ε andf-ε curves indicate that a “rule of mixtures” relation based on the “static” strengthening effect of the transformation product describes the plastic flow behavior reasonably well above Ms σ, but there is also a dynamic “transformation softening” contribution which becomes dominant below Ms σ due to the operation of transformation plasticity as a deformation mechanism. Temperature sensitivity of the transformation kinetics and associated flow behavior is greatest above Ms σ. Less temperature-sensitive TRIP steels could be obtained by designing alloys to operate with optimum mechanical properties below Ms σ.

Keywords

Austenite Martensite Metallurgical Transaction Trip Steel Stable Austenite 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© American Society for Metals and the Metallurgical Society of A1ME 1978

Authors and Affiliations

  • G. B. Olson
    • 1
  • M. Azrin
    • 2
  1. 1.Department of Materials Science and EngineeringMIT, Cambridge
  2. 2.Army Materials and Mechanics Research CenterWatertown

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