Constitutive relations for transformation plasticity have been derived from martensitic transformation kinetic theory, predicting flow-stress as a function of strain, strain-rate, temperature, and stress state. The stress-strain curve can exhibit upward curvature under the combined influence of the softening contribution of the transformation as a deformation mechanism and the hardening contribution of the transformation product. This shape provides a maximum stability of plastic flow and quantitatively accounts for observed enhancement of uniform ductility in TRIP steels. In combination with transformation dilatation effects, the flow stabilizing influence also accounts for a major transformation toughening effect observed when ductile fracture is controlled by plastic shear instability. The principles have now been applied to both homogeneous and dispersed-phase alloy systems.
|Original language||English (US)|
|Title of host publication||Unknown Host Publication Title|
|Publisher||Metallurgical Soc of AIME|
|Number of pages||24|
|State||Published - Dec 1 1986|
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