Effect of testing temperature and strain rate on the transformation behaviour of retained austenite in low-alloyed multiphase steel

The influence of temperature and strain rate on the evolution of the retained austenite content during plastic straining has been studied by tensile tests performed at 4 x 10(-4). 10(-2) and 0.4 s(-1) between -100 and 450 degrees C. Up to 150 degrees C, the austenitic volume fraction mechanically transformed decreases with increasing testing temperature being almost independent of strain rate. In contrast, above 150 degrees C the martensite transformation depends on testing temperature and strain rate since it is related to the ability of carbon atoms for pinning dislocations. (C) 2009 Published by Elsevier B.V.