|About this Abstract
||MS&T23: Materials Science & Technology
||Advances in Understanding of Martensite in Steels II
||Excess Solute Carbon and Retained Tetragonality in Autotempered and Tempered Fe-C Lath Martensite
||Naoki Maruyama, Shinichiro Tabata
|On-Site Speaker (Planned)
The tetragonality and excess solute C in the matrix of autotempered low-to-medium C ferrous martensite with the M<sub>s</sub> well above room temperature have been revealed by XRD analysis and atom probe measurement. In order to elucidate the mechanism of the persistence of excess solute C in lath martensite, we investigated the changes in the crystal structure and solute C content in the matrix after quenching and tempering of 1Mn-C (C:0.07-0.8 mass%) steels, and the effect of Si addition. The amount of excess solute C was found to be uniquely correlated with retained tetragonality c/a irrespective of tempering conditions after martensitic transformation and C contents in the steels. The kinetics of the decrease in solute C in (auto-)tempering is presumably dominated by the kinetics of the lattice strain relaxation caused by C precipitation and dislocation migration in martensite matrix.