Unified Theory of Transformation Plasticity and The Effect on Quenching Simulation

T. Inoue, H. Wakamatsu:
UNIFIED THEORY OF TRANSFORMATION PLASTICITY AND  THE EFFECT ON QUENCHING SIMULATION
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New challenges in heat treatment and surface engineering – conference in honour of prof. Božidar Liščić (09 – 12 June 2009, Dubrovnik – Cavtat, Croatia)

ABSTRACT:
A phenomenological mechanism of transformation plasticity (TP) is discussed, in the first part of the paper, why it takes place under a stress level even lower than the characteristic yield stress of mother phase:  This is principally based on the difference in thermal expansion coefficient in both phases.  Bearing in mind that it is also a kind of plastic strain, a unified plastic flow theory is derived by introducing the effect of progressing new phase into the yield function of stress, temperature and plasticity related parameters.  Experimental results of the TP coefficient will be shown in the following section for some steels under tensile and compressive stress.  As examples of the application of the theory and the data, metallo-thermo-mechanical simulation for a quenched blank gear wheel is executed to demonstrate the effect of TP.


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