Effect of Solution Carbon and Retained Austenite Film on Development of Deformation Structure of Low Carbon Lath Martensite

Abstract

The development of deformation structure in the low carbon lath martensite steel was clarified using transmission electron microscopy observation with Kikuchi pattern analysis. The retained austenite films on the martensite lath boundaries transform to high carbon martensite films by light deformation, and the high carbon martensite films protect martensite lath boundaries from deformation. The specific deformation structures of low carbon lath martensite, such as kinked laths, irregularly bent lamellas and lamellar dislocation cells are formed by the retained austenite films. The tempered lath martensite structure without retained austenite films easily disappears by light deformation. We also clarified the relationship between the mechanical properties, such as work-hardening ratio, and the development of the the deformation structure.