Understanding Strength-Toughness Combination of Microalloyed Steels Processed for Large Structural Applications through Stereological Analysis

摘要

Stereological analysis involves relating three-dimensional microstructural parameters notably volume fraction, surface area per unit volume, length per unit volume, and number per unit volume to the observations made on two-dimensional images of microstructures. Classical stereology concerns relationship between measurements on two-dimensional plane-section images and the stereological parameters. The present paper underscores the effective application of stereological analysis in understanding the variation in strength-toughness combination of microalloyed steels characterized by similar microstuctural constituents. The microstructures of steels were quantified in terms of stereological parameters, notably mean intercept length (L{sub}α) of polygonal ferrite, pearlite colony and their size distribution, ferrite grain boundary surface area per unit volume [S{sub}V]{sub}α, total grain boundary surface area per unit volume [S{sub}V]{sub}T, contiguity ratio (C{sub}α) of ferrite grains and pearlite colonies, pearlite interlamellar spacing and its distribution. Interestingly, the toughness is linearly related to contiguity ratio and the mean intercept length.