EFFECT OF STRAIN AND STRAIN PATH ON DEFORMATION TWINNING AND STRAIN INDUCED MARTENSITE IN AISI 316L AND 304L AUSTENITIC STAINLESS STEEL

摘要

AISI 304L and 316L austenitic stainless steel sheets were deformed at different strain and strain path using LDH (limiting dome height) method. Deformed microstructures had two interesting features- deformation twins and strain induced martensite. The former originated from decay of prior annealing twins as well as through formation of new deformation twins. Strain induced martensite formation was strongly affected by the strain and strain path. This was generalized in terms of frequency and size advantage - a classification based purely on martensite grain size. The frequency advantage was related to the presence of microstructural heterogeneities, while the growth advantage appears to originate from relative tolerance around 45°<001> Bain orientation relationship.