Determination of carbon distributions in quenched and partitioned microstructures using nanoscale secondary ion mass spectroscopy

A multi-modal characterization technique, which combines nanoscale secondary ion mass spectroscopy (Nano-SIMS) with a spatial resolution of ∼100 nm and electron back scatter diffraction (EBSD) to determine carbon distributions in austenite and martensite in a quenched and partitioned (Q&P) Fe-0.29C-2.95Mn-1.59Si steel is presented. Significant carbon enrichment of austenite was measured with decreased levels of carbon in martensite, supporting the carbon partitioning mechanism. Fresh untempered martensite could be identified, and different degrees of enrichment were observed for blocky and lath austenite.