Influence of martensite and grain size on the mechanical behavior of austenitic Fe–C–Mn–Ni–Al medium Mn steels with TWIP mechanism under uniaxial tension/compression and micromechanical creep

Manuel Francisco Melendrez Castro, Angelo Oñate*, Martin Castro, Juan Pablo Sanhueza, Víctor Tuninetti, David Rojas

*Autor correspondiente de este trabajo

Producción científica: Contribución a una revistaArtículorevisión exhaustiva

Resumen

Medium Mn steels with induced plasticity mechanisms have effectively addressed the high-strength and ductility requirements for structural applications. However, there is still uncertainty about the impact of residual martensite on medium Mn steels with an austenitic matrix under uniaxial tension and compression. Furthermore, research on the influence of grain size through incomplete recrystallization in medium Mn alloys is scarce. In this context, our study focused on design and manufacturing a medium Mn Fe–C–Mn–Ni–Al alloy through controlled atmosphere casting incorporating martensite, aiming to analyze its effects under uniaxial stress conditions. Thermomechanical and annealing heat treatments were applied to control grain growth and nucleation of new grains, allowing us to explore how grain size affects the twinning process and mechanical reinforcement in the alloy. Microstructural characterization techniques, including optical and scanning electron microscopy, were employed to assess the mechanical response and damage mechanisms. Mechanical tests included tension, compression, and nanoindentation. The results indicated that residual martensite generates an accelerated damage mechanism under tension due to co-deformation at the interface with austenite, resulting in crack nucleation and rapid propagation through mode I fracture. Consequently, ductility in tension significantly decreases, while no apparent failure is observed during the compression deformation process. Furthermore, incomplete recrystallization was observed to enhance the creep response in both tension and compression. The strain hardening rate results revealed the activation of primary twinning in tension and both primary and secondary twinning in compression for annealed samples. Nanoindentation tests confirmed the presence of twinning and revealed that diffusion creep and grain boundary sliding are the predominant creep mechanisms.
Idioma originalInglés
Número de artículo129966
Páginas (desde-hasta)1
Número de páginas15
PublicaciónMaterials Chemistry and Physics
Volumen328
DOI
EstadoPublicada - 2024

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Áreas temáticas de ASJC Scopus

  • Ciencia de los Materiales General

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