TY - JOUR
T1 - Ti-Mo microalloyed medium Mn steels
T2 - Precipitation and strengthening mechanism
AU - Wang, S. Y.
AU - Wang, C. Z.
AU - Li, H. Y.
AU - Xu, D. F.
AU - Zhang, H. T.
AU - Xiao, N.
AU - Cai, M. H.
AU - Lee, Y. K.
N1 - Publisher Copyright:
© 2024 Elsevier B.V.
PY - 2024/9
Y1 - 2024/9
N2 - Medium-Mn steels possess an exceptional strength-ductility balance but normally relatively low yield strength, which hinders their practical applications especially in ultra-high strength structural components. In this study, the simultaneous addition of Ti and Mo was proposed to improve the yield strength of medium-Mn steels, together with the systematic experimental and theoretical investigations on the precipitation behavior of (Ti, Mo)C carbides and its effects on the microstructure-properties relationship. The addition of Ti and Mo increases yield strength by 150∼350 MPa and ultimate tensile strength by 55∼320 MPa without a significant loss of ductility. Based on the intercritically annealed microstructure close to equilibrium as well as the nucleation and growth kinetic theory, the Ti–Mo addition can reduce the fraction of austenite, but increase the mechanical stability of austenite by refining the mean grain size of austenite. Mo was found to increase the precipitate density of (TixMo1-x)C by lowering the interfacial energy between the nano-precipitates and the matrix, and reduce the mean size of precipitates. A maximum increment in yield strength (∼350 MPa) was achieved at 610 °C, which was mainly attributed to the combined effects of grain refinement and precipitation hardening due to the addition of Ti and Mo.
AB - Medium-Mn steels possess an exceptional strength-ductility balance but normally relatively low yield strength, which hinders their practical applications especially in ultra-high strength structural components. In this study, the simultaneous addition of Ti and Mo was proposed to improve the yield strength of medium-Mn steels, together with the systematic experimental and theoretical investigations on the precipitation behavior of (Ti, Mo)C carbides and its effects on the microstructure-properties relationship. The addition of Ti and Mo increases yield strength by 150∼350 MPa and ultimate tensile strength by 55∼320 MPa without a significant loss of ductility. Based on the intercritically annealed microstructure close to equilibrium as well as the nucleation and growth kinetic theory, the Ti–Mo addition can reduce the fraction of austenite, but increase the mechanical stability of austenite by refining the mean grain size of austenite. Mo was found to increase the precipitate density of (TixMo1-x)C by lowering the interfacial energy between the nano-precipitates and the matrix, and reduce the mean size of precipitates. A maximum increment in yield strength (∼350 MPa) was achieved at 610 °C, which was mainly attributed to the combined effects of grain refinement and precipitation hardening due to the addition of Ti and Mo.
KW - Mechanical properties
KW - Medium-Mn steel
KW - Microalloying
KW - Microstructural evolution
KW - Precipitation kinetics
KW - Strengthening mechanism
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U2 - 10.1016/j.msea.2024.146866
DO - 10.1016/j.msea.2024.146866
M3 - Article
AN - SCOPUS:85196629380
SN - 0921-5093
VL - 909
JO - Materials Science and Engineering: A
JF - Materials Science and Engineering: A
M1 - 146866
ER -