首页|Mechanisms of strength-plasticity enhancement and stress-induced phase transition in a medium-carbon low-alloy steel

Mechanisms of strength-plasticity enhancement and stress-induced phase transition in a medium-carbon low-alloy steel

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A medium-carbon low-alloy steel with designed chemical composition was investigated.The steel exhibits an excellent product of strength and elongation value of 31,832 MPa%through quenching and partitioning treatment,with a tensile strength of 1413 MPa and elongation of 22%.X-ray diffraction analysis and transmission electron microscopy charac-terizations confirm that the retained austenite in the specimens undergoes stress-induced phase transformation to the martensite and hexagonal phases,namely the transformation-induced plasticity(TRIP)effect is triggered.This TRIP effect,triggered by the stress-induced phase transition of retained austenite,is responsible for the excellent mechanical properties obtained in the steel.For further investigating the stress-induced phase transition mechanism,thermodynamic methods are applied.Gibbs free energy of face-centered cubic-Fe,ε-Fe,ω-Fe and body-centered cubic-Fe associated with the stress-induced phase transition was calculated using molecular dynamics simulations,and a calculation method of strain energy in thermodynamic units for the stress-induced martensitic transformation is presented.The final results reveal the process and thermodynamic mechanism of stress-induced martensitic transformation in medium-carbon steels,in which the hexagonal phase can participate in the process as an intermediate product.

Medium-carbon low-alloy steelProduct of strength and elongationStress-induced martensitic transformationTransformation-induced plasticity effectω-Fe phase

Meng-wei Lu、Xin Chen、Wen-xi Liu、Yu-ru Chen、Qi Li、Kai Wang、Zu-min Wang、Yuan Huang

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Institute of Advanced Metallic Materials,School of Materials Science and Engineering,Tianjin University,Tianjin 300350,China

National Key Research and Development Program of China

2018YFB0703904

2024

钢铁研究学报(英文版)
钢铁研究总院

钢铁研究学报(英文版)

CSTPCD
影响因子:0.584
ISSN:1006-706X
年,卷(期):2024.31(9)