Unveiling the effects of Mn, Cr, Al, and Si on the low-temperature tempering behaviors of high-carbon martensite

Zhang, Y.*; Marusawa, Kenji*; Kudo, Kohei*; Morooka, Satoshi  ; Gong, W.   ; Harjo, S.   ; Miyamoto, Goro*; Furuhara, Tadashi*

This study examines how substitutional alloying elements (Mn, Cr, Al, and Si) influence low-temperature tempering reactions in high carbon martensitic steels. Through comprehensive experimental techniques including neutron diffraction et al., the work clarifies how alloying modifies tempering kinetics by affecting carbon diffusion and phase nucleation. Al and Cr strongly suppress martensite tetragonality reduction and carbon redistribution, while retained austenite decomposes in two stages that are selectively delayed by different alloying elements. Overall, the tempering sequence and kinetics are shown to be governed by alloying-dependent control of carbon mobility and phase transformations.