Experimental studies of Portevin-Le Chatelier plastic instabilities in carbon-manganese steels by infrared pyrometry

Ranc, Nicolas; Du, Wenbo; Ranc, Isabelle; Wagner, Danièle

doi:10.1016/j.msea.2016.03.096

Cited by 15 publications

(16 citation statements)

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Section: The Nature Of Plc Effect In Steelsmentioning

confidence: 99%

“…Several authors reported that the NSRS effect is related to the stability of RA due to adiabatic heating at high strain rates. Generally, adiabatic heating affects both the DSA and NSRS by increased diffusion intensity [8,9,15,49]. Callahan et al [52] reported that the NSRS in 0.2C-5Mn-2.5Al TRIP steel is due to the effect of adiabatic heating, which increases the stability of retained austenite, and thus reduces the work hardening rate.…”

Section: Effect Of Strain Rate On the Plc Effectmentioning

confidence: 99%

“…In available literature, there are several theories explaining the mechanism of serrated flow in steels. Generally, a value of critical strain for activation of the PLC effect is related to several factors, which can be classified as interior factors: solute atom concentration (especially C and N content), dislocation density, grain size and external factors, including deformation temperature and strain rate [3,4,8,9]. The heterogeneous deformation associated with the increase in flow stress can lead to multiple cracks during sheet molding.…”

Section: Introductionmentioning

confidence: 99%

“…This effect is called negative strain rate sensitivity (NSRS). The main factors causing the NSRS are the DSA suppression by an increment in dislocations velocity and the inhibition of deformation twinning under high strain rates [8,9].The heterogeneous plastic deformation phenomenon is usually preceded by a homogeneous deformation. A strain level at which the serrations appear is referred to a critical strain initiating the PLC effect.…”

mentioning

confidence: 99%

“…A strain level at which the serrations appear is referred to a critical strain initiating the PLC effect. The value of critical strain is related to several factors including solute atom concentration, dislocation density, grain size, deformation temperature and strain rate [3,4,8,9]. Equation (1) includes most of these factors.…”

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confidence: 99%

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Explanation of the PLC Effect in Advanced High-Strength Medium-Mn Steels. A Review

et al. 2019

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The paper reviews the recent works concerning the Portevin-Le Chatelier (PLC) effect in Advanced High-Strength Steels (AHSSs) with a special attention to high-strength medium-manganese steels. Theories explaining the mechanism of the plastic instability phenomenon in steels with medium-and high-Mn contents were discussed. The relationships between microstructural effects such as TRIP (Transformation-Induced Plasticity), TWIP (Twinning-Induced Plasticity) and the PLC effect were characterized. The effects of processing conditions including a deformation state (hot-rolled and cold-rolled) and strain parameters (deformation temperature, strain rate) were addressed. Factors affecting the value of critical strain for the activation of serrated flow behavior in particular in medium-manganese steels were described.The explanation of the Portevin-Le Chatelier mechanism in medium-Mn steels showing the TRIP effect is a complicated issue because of their microstructure consisting of several phases, as well as the TRIP effect exhibited by these steels. The exact characteristics of the factors affecting the PLC effect in AHSS is very important, both from a research point of view and their industrial implementation. This overview concerns the PLC phenomenon in Advanced High Strength Steels (AHSSs), with particular emphasis on advanced medium-Mn TRIP steels. The Nature of PLC Effect in SteelsThe plastic instability phenomenon occurring during the deformation of metallic materials shows two most common forms of propagative bands: Lüders and Portevin-Le Chatelier bands. The Lüders bands refer to the regions of localized strain. They form immediately after the onset of plastic deformation from the yield point drop, followed to a dominant stage of the stress plateau stage. Lüders bands are commonly caused by static strain aging (SSA) [13]. Static strain aging is characterized by an increase in strength properties associated with a decrease in plasticity. The PLC bands are represented by characteristic serrations on stress-strain curves. PLC bands are usually related to the dynamic strain aging (DSA) effect. The occurrence of the PLC bands is much more erratic, and can be observed in various forms (serration types) in comparison to the Lüders bands.There are several theories which explain the PLC effect in metallic materials. However, none has been so far clearly confirmed. The first interpretation of this phenomenon was proposed by Cottrell [1]. From his point of view, the PLC effect is related to the interactions between solute atoms, such as C or N, and mobile dislocations. The presence of serrations on a tensile curve is associated with the rapid release of dislocations from the atmospheres of dissolved atoms, which block their movement. This model is based on the assumption that atmospheres are formed around dislocations due to volume diffusion. In the presence of substitution atoms, diffusion is facilitated by vacancies resulting from plastic deformation. The interstitial gaps located in the vicinity of the dislocation are enl...

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Section: The Nature Of Plc Effect In Steelsmentioning

confidence: 99%