Effect of carbon content on microstructure and mechanical properties of Mn-heterogeneous quenching and partitioning steels

TY - JOUR

T1 - Effect of carbon content on microstructure and mechanical properties of Mn-heterogeneous quenching and partitioning steels

AU - Zhang, Chao

AU - Li, Zhao Dong

AU - Cao, Yan Guang

AU - Yang, De Zhen

AU - Zhang, Hao

AU - Cheng, Xing Wang

AU - Xiong, Zhi Ping

N1 - Publisher Copyright: © CISRI Boyuan Publishing Co., Ltd 2026.

PY - 2026/4

Y1 - 2026/4

N2 - Correlation of quenching temperature and bulk carbon content with microstructure-properties evolution in Mn-heterogeneous quenching and partitioning (Q&P) steels (0.3C and 0.4C) was systematically investigated. Two critical quenching temperature points were identified where ghost pearlite fraction peaks (70 °C for 0.4C, 130 °C for 0.3C), with low carbon 0.3C steel displaying a smoother decrease in ghost pearlite fraction due to preferential martensite transformation over coalescence at high quenching temperatures. Compared to 0.4C steel (~ 110 °C), superior ductility (22% elongation) across an extended temperature window (130–210 °C) was obtained in 0.3C steel, resulting from metastable retained austenite and progressive transformation induced plasticity effects facilitated by lower carbon content. Meanwhile, submicron martensite refinement (120–140 nm) in Mn-depleted regions counteracts martensite lath coalescence in conventional low carbon steels, maintaining more pronounced decrease in yield strength (542 vs. 348 MPa) in 0.3C steel (with ~ 400 nm conventional martensite laths) under the same 80 °C quenching temperature variation. The coordinated utilization of chemical heterogeneity with bulk composition design provides an effective pathway to enhance mechanical performance of Q&P steels.

AB - Correlation of quenching temperature and bulk carbon content with microstructure-properties evolution in Mn-heterogeneous quenching and partitioning (Q&P) steels (0.3C and 0.4C) was systematically investigated. Two critical quenching temperature points were identified where ghost pearlite fraction peaks (70 °C for 0.4C, 130 °C for 0.3C), with low carbon 0.3C steel displaying a smoother decrease in ghost pearlite fraction due to preferential martensite transformation over coalescence at high quenching temperatures. Compared to 0.4C steel (~ 110 °C), superior ductility (22% elongation) across an extended temperature window (130–210 °C) was obtained in 0.3C steel, resulting from metastable retained austenite and progressive transformation induced plasticity effects facilitated by lower carbon content. Meanwhile, submicron martensite refinement (120–140 nm) in Mn-depleted regions counteracts martensite lath coalescence in conventional low carbon steels, maintaining more pronounced decrease in yield strength (542 vs. 348 MPa) in 0.3C steel (with ~ 400 nm conventional martensite laths) under the same 80 °C quenching temperature variation. The coordinated utilization of chemical heterogeneity with bulk composition design provides an effective pathway to enhance mechanical performance of Q&P steels.

KW - Carbon content

KW - Chemical heterogeneity

KW - Martensite

KW - Mechanical property

KW - Quenching temperature

UR - https://www.scopus.com/pages/publications/105034730601

U2 - 10.1007/s42243-026-01751-1

DO - 10.1007/s42243-026-01751-1

M3 - Article

AN - SCOPUS:105034730601

SN - 1006-706X

VL - 33

JO - Journal of Iron and Steel Research International

JF - Journal of Iron and Steel Research International

IS - 5

M1 - 144

ER -