Manganese controlled transformation and twinning of the nanoscale austenite in low-carbon-medium-Mn steel

Xue, W.Y.; Zhang, H.F.; Shen, Y.F.; Jia, Nan

doi:10.1016/j.msea.2021.142162

Cited by 18 publications

(1 citation statement)

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“…Among various TMT processes, intercritical annealing (IA) after cold-rolling, warm-rolling, or hotrolling is a common route to produce an ultrafine-grained microstructure consisting of α ferrite and/or α 0 martensite with retained austenite. [6,7,[9][10][11][12][13][14][15][16][17][18][19][20] During IA, reverted austenite is formed owing to the partitioning of alloying elements, especially Mn and C. The IA time and temperature, therefore, control the extent of the enrichment and consequently the stability of austenite. They also determine the fraction and grain size of the reverted austenite.…”

Section: Introductionmentioning

confidence: 99%

Nanosized Lamellar Structures and Tensile Properties of Intercritical‐Annealed Medium Mn Steels Containing Multiphases

Trang

Jeong

Lee

et al. 2022

steel research int.

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The effect of extended intercritical annealing time on the changes of the microstructure and tensile properties is studied in a medium Mn steel. Nanosized lamellar structures are formed after intercritical annealing at 550 °C for 8 and 16 h; they consist of mainly tempered‐α′ martensite with retained austenite. Many cementite precipitates are observed in the tempered‐α′ martensite matrix and at the high‐angle boundaries. The orientation relationship between θ‐cementite and tempered‐α′ martensite is identified to be ()θ//()tempered‐α′, [011]θ//[011]tempered‐α′, and []θ//[]tempered‐α′. Fresh α′ martensite is detected between the tempered‐α′ martensite and austenite lamellae in the quenched specimens. The fresh α′ martensite is formed due to partial martensitic transformation of austenite upon cooling. The fractions of cementite and fresh α′ martensite increase with extended annealing time, leading to reduced austenite fraction after quenching. Additional baking treatment at 200 °C increases yield stress and elongation due to the stabilization of the austenite. This study provides a detailed understanding of these complex nanosized microstructures and discusses the key factors governing their yield stresses and work hardening behaviors.

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