Propiedades mecánicas a tracción y mecanismos de endurecimiento de un acero TWIP a altas velocidades de deformación: relación de Hall-Petch

Abstract

RESUMEN:Se ha estudiado la influencia de la velocidad de deformación y tamaño de grano en las propiedades mecánicas de un acero TWIP austenítico de composición 22% Mn, 0,6% C (% en masa). Para las velocidades de deformación de 9,4 s −1 y 265 s −1 a temperatura ambiente, se ha observado un comportamiento cuasi-lineal en las curvas tensión-deformación, típico en estos materiales que deforman por maclaje. Se ha mostrado que a altas velocidades de deformación la región con tasa de endurecimiento constante observada en aceros TWIP disminuye notablemente. Además, se ha obtenido la relación de Hall-Petch para cada velocidad de deformación. La pendiente de Hall-Petch K HP incrementa en función de la deformación en todos los casos. La dependencia de K HP con la velocidad de deformación podría ser causada por el calentamiento adiabático. ABSTRACT:Tensile properties and strengthening mechanisms of a TWIP steel at high strain rate: Hall-Petch relationship. The influence of strain rate and grain size on the mechanical properties of a 22% Mn, 0.6% C (mass %) austenitic TWIP steel has been studied. A typical quasi-linear stress-strain behaviour of TWIP steels that deform by twinning has been observed at strain rates of 9.4 s −1 and 265 s −1 and room temperature. At high strain rates, the constant work -hardening rate region typically observed in TWIP steel clearly shortens. In addition, the Hall-Petch relationship has been obtained for each strain rate. The Hall-Petch slope K HP increases as a function of strain in all cases. The dependence of the K HP on the strain rate could be adiabatic heating.

A comparison of the internal stresses in a transformation-induced plasticity-assisted steel and a twinning-induced plasticity steel

“…In a similar manner, this relationship is very similar to that obtained for TWIP steel as it is shown in Figure 6(b) published from the previous research work for quasi-static strain rate [23]. From bibliography, such relationships for TWIP steels are very similar for quasi-static strain rate [31] and higher strain rates [32] for the same strain levels of flow stress.

Figure 6 Flow stress at different fixed plastic strain levels versus the inverse of the square root of the grain size.

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“…In a similar manner, this relationship is very similar to that obtained for TWIP steel as it is shown in Figure 6(b) published from the previous research work for quasistatic strain rate [23]. From bibliography, such relationships for TWIP steels are very similar for quasi-static strain rate [31] and higher strain rates [32] for the same strain levels of flow stress. Furthermore, respectively for both TRIP-assisted steel and TWIP steel the H-P slope takes values from 320.16 MPa m 1/2 -356.56 MPa m 1/2 at the elastic limit and 405 MPa m 1/2 -487.88 MPa m 1/2 at 15% of true plastic strain; i.e.…”

Effects of temperature and strain rate in strain hardening in torsion of a twinning-induced plasticity steel

“…This mechanism conducts to the progressively subdivision of the original austenite grains by the incessant activation of mechanical twins whose boundaries are strong barriers that block both expansion of other mechanical twins that intersect each other and the dislocations glide. Consequently, each original grain quickly becomes an aggregate of nanometric parallelepipeds, which represents a dynamic mechanism of Hall-Petch contribution strengthening [12][13][14][15]. In addition to this dynamic mechanism, which contributes as an isotropic hardening, substantial kinematic hardening (giving rise to the Bauschinger-type back stress effect) was involved which accounts for an important part of the flow stress [16][17][18][19][20][21].…”

Un estudio adicional de la cinética de recristalización y crecimiento de grano del acero twip laminado en frío

“…Over last decades, the twinning -induced plasticity Fe-Mn-C (TWIP) steels have been the focus on huge amount of research works due to their prominent strength -ductility compounding which develops from the occurrence of extended mechanical twinning during plastic deformation under mechanical loads Frommeyer et al, 2000;Cornette et al, 2005;Scott et al, 2006;Bouaziz et al, 2008;Hamada et al, 2010;Bouaziz et al, 2011;De Cooman et al, 2011;Galán et al, 2012;Gil Sevillano and De las Cuevas, 2012;Chen et al, 2013;De las Cuevas et al, 2014;Ghasri-Khouzani and McDermid, 2015;Pierce et al, 2015;De las Cuevas and Gil Sevillano, 2017).…”