Design of an Effective Heat Treatment Involving Intercritical Hardening for High Strength/High Elongation of 0.2C–3Al–(6–8.5)Mn–Fe TRIP Steels: Microstructural Evolution and Deformation Behavior
| Autor: | Devesh Misra, Huiping Li, Yanjie Mou, Zhichao Li, Lianfang He, Zhang Xiaoteng |
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| Rok vydání: | 2019 |
| Předmět: |
010302 applied physics
Austenite Materials science heat treatment deformation behavior microstructure deformation Metals and Alloys 02 engineering and technology mechanical properties Plasticity 021001 nanoscience & nanotechnology Microstructure 01 natural sciences Diffusionless transformation Martensite 0103 physical sciences Ultimate tensile strength discontinuous transformation during deformation Hardening (metallurgy) General Materials Science Tempering Composite material 0210 nano-technology |
| Zdroj: | Metals Volume 9 Issue 12 |
| ISSN: | 2075-4701 |
| Popis: | High strength/high elongation continues to be the primary challenge and focus for medium-Mn steels. It is elucidated herein via critical experimental analysis that the cumulative contribution of transformation-induced plasticity (TRIP) and microstructural constituents governs high strength/high elongation in 0.2C&ndash 3Al&ndash (6&ndash 8.5)Mn&ndash Fe steels. This was enabled by an effective heat treatment involving a combination of intercritical hardening and tempering to obtain high strength/high ductility. An excellent combination of high ultimate tensile strength of 935&ndash 1112 MPa and total elongation of 35&ndash 40% was obtained when the steels were subjected to intercritical hardening in the temperature range of 700&ndash 750 ° C and low tempering at 200 ° C. The intercritical hardening impacted the coexistence of austenite, ferrite, and martensite, such that the deformation behavior varied with the Mn content. The excellent obtained properties of the steels are attributed to the cumulative contribution of the enhanced TRIP effect of austenite and the microstructural constituents, ferrite and martensite. The discontinuous TRIP effect during deformation involved stress relaxation, which was responsible for the high ductility. Lamellar austenite, unlike the equiaxed microstructure, is envisaged to induce stress relaxation during martensitic transformation, resulting in the discontinuous TRIP effect. |
| Databáze: | OpenAIRE |
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