Effect of Carbon Partitioning on Abnormal Martensite Hardening in a Conventional Quench and Temper Medium Silicon Low Alloy Steel under Ferrite-Martensite Dual-Phase Microstructure

The purpose of this research work was to investigate the effect of carbon partitioning within ferrite and prior austenite (martensite) during progress of ferrite formation and consequently its relation to the associated martensite hardening in a medium silicon low alloy conventional quench and temper steel. For this aim, several ferrite-martensite dual-phase (DP) samples containing various volume fractions of ferrite and martensite microphases were developed. The X-ray diffraction and electron microscopy with spot and line-scan X-ray energy-dispersive spectroscopy (EDS) for carbon analysis were used in conjunction with light microscopy and hardness test to follow the variation of carbon partitioning within ferrite and prior austenite (martensite) regions and consequently the associated martensite hardening in the DP samples.