Room temperature mechanical properties and microstructure of a low alloyed TRIP-assisted steel subjected to one-step and two-step quenching and partitioning process
| Autor: | Hamid Reza Abedi, M. Karam-Abian, Abbas Zarei-Hanzaki, A. Zinsaz-Borujerdi, H. Ding, D. Han, Nousha Kheradmand |
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| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Austenite Quenching education.field_of_study Materials science Bainite Mechanical Engineering Population 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Mechanics of Materials Martensite Diffusionless transformation 0103 physical sciences Volume fraction General Materials Science Lamellar structure Composite material 0210 nano-technology education |
| Zdroj: | Materials Science and Engineering: A. 725:341-349 |
| ISSN: | 0921-5093 |
| DOI: | 10.1016/j.msea.2018.04.042 |
| Popis: | The capability of one-step and two-step quenching and partitioning processes (Q&P) to treat the microstructure of a low alloyed TRIP-assisted steel was considered. The treated microstructures primarily consisted of lath martensite, retained austenite, lower bainite, and fresh martensite. Two various types of retained austenite in respect of size and morphologies were observed: blocky and film-like retained austenite. Short holding times were appropriate for carbon enrichment of the retained austenite. However, the volume fraction and carbon concentration of retained austenite vs. partitioning time followed an opposite trends in two step processed microstructures. This was attributed to the competitive processes of bainite or epsilon carbide formation at the specified partitioning temperature. The nano indentation experiments were employed to assess the local mechanical properties of individual phases specifically martensite and enriched retained austenite. The frequent pop-in in load-displacement curves indicated the capability of enriched austenite for martensitic transformation. Owning to the higher diffusion rate, the carbon concentration was relatively higher in two-step processed microstructures. In addition, film like or lamellar morphologies (which hold higher population in partitioned structures at 400 °C) possessed better transformation stability rather than a blocky type, which tends to transform to martensite under higher amount of strain. The evolution of mechanical properties was discussed relying on the variations of volume fraction, morphology and carbon concentration of retained austenite. |
| Databáze: | OpenAIRE |
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