Kinetics of anomalous multi-step formation of lath martensite in steel

Villa, Matteo; Pantleon, Karen; Reich, Michael; Keßler, Olaf

doi:10.1016/j.actamat.2014.08.031

Cited by 23 publications

(28 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The fitting of both sets of Q values together illustrates that the austenite grain size/mean intercept is not a relevant variable because the martensite units run across the grain boundaries. Villa et al 28 observed isothermal martensite kinetics on the isochronal cooling a Fe-Cr-Ni-Cu alloy which was attributed to thermally activated growth of athermal nucleated lath martensite. Laughlin et al 29 generalized the discussion of thermally-activated stages in the martensite transformation curve by considering the relative position of the M S temperature and the nose of the thermal-activated martensite transformation, and the imposed cooling rate.…”

Section: Discussionmentioning

confidence: 99%

Martensite Transformation Intergrain and Intragrain Autocatalysis in Fe-Ni alloys

Guimarães

Rios

2017

Mat. Res.

View full text Add to dashboard Cite

This work presents a consolidated view of the autocatalysis, thermal and entropic effects in martensitic transformation of polycrystalline Fe-31wt%Ni-0.02wt%C, which has been a standard material for the investigation of fundamental aspects of the martensite transformation. The present work is based on the description of classical microstructure descriptors of the transformation and on generally accepted concepts regarding the martensitic transformation in iron base alloys. Present work agrees with the view that the autocatalysis is a means by which the martensite transformation promotes further nucleation and growth. Autocatalysis induces the nucleation and growth of secondary plates in addition to the relatively small number of primary nucleation sites and their corresponding primary plates. We demonstrate that autocatalysis can be factored out into intragrain and intergrain components. The analysis of these factors establishes that intragrain autocatalysis is athermal but intergrain autocatalysis possess an Arrhenius temperature dependence. The reasons for such a behavior are discussed in detail.

show abstract

Section: Discussionmentioning

confidence: 99%

Martensite Transformation Intergrain and Intragrain Autocatalysis in Fe-Ni alloys

Guimarães

Rios

2017

Mat. Res.

View full text Add to dashboard Cite

show abstract

“…10, a train of transformation rate maxima was observed with dilatometry during cooling of a Fe-CrNi-Cu martensitic stainless steel at cooling rates ranging from 0.015 to 500 K min -1 , and anomalous transforma-tion kinetics was observed in the cooling rate range 1.5-50 K min -1…”

Section: Introductionmentioning

confidence: 98%

“…8 On the other hand, austenite to martensite transformation kinetics characterised by a series of alternating accelerations and decelerations of the trans-formation on cooling is considered an anomaly. 3,7,9,10 Such anomalous transformation kinetics differs from burst kinetics for the reproducibility 9,10 and the timescale of the transformation steps, which is in the range 1-10 4 s.…”

Section: Introductionmentioning

confidence: 99%

“…17 Conversely, in Ref. 10, the train of transformation rate maxima was interpreted as the result of the interplay between the driving force for thermally activated autocatalytic martensite formation and the counteracting mechanical stabilisation of the austenite (see below) during the transformation. Moreover, according to Ref.…”

Section: Introductionmentioning

confidence: 99%

“…9 and 10. The transformation kinetics was referred to as unusual 9 and anomalous, 10 respectively. In Ref.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Anomalous kinetics of lath martensite formation in stainless steel

Villa¹,

Hansen

Pantleon³

et al. 2015

Materials Science and Technology

View full text Add to dashboard Cite

The kinetics of lath martensite formation in Fe-17.3 wt-%Cr-7.1 wt-%Ni-1.1 wt-%Al-0.08 wt-%C stainless steel was investigated with magnetometry and microscopy. Lath martensite forms during cooling, heating and isothermally. For the first time, it is shown by magnetometry during extremely slow isochronal cooling that transformation rate maxima occur, which are interrupted by virtually transformation free temperature regions. Microscopy confirms martensite formation after athermal nucleation of clusters followed by their time dependent growth. The observations are interpreted in terms of time dependent autocatalytic lath martensite formation followed by mechanical stabilisation of austenite during the transformation process.

show abstract

Effect of Different Quenching Methods on the Microstructure and Mechanical Properties of 30MnB5NbTi

Wang,

Song,

Chen

et al. 2024

steel research int.

View full text Add to dashboard Cite

The effects of different quenching methods on the microstructure and mechanical properties of 30MnB5NbTi hot stamping steel are investigated, and the quenched microstructure is characterized by scanning electron microscope (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). The mechanical properties are evaluated by uniaxial tensile test. The results reveal that, in comparison to die quenching, oil quenching, or air cooling, water‐quenched samples (tempered after water quenching, die quenching and oil quenching) exhibit the highest ultimate tensile strength (UTS) and yield strength (YS), reaching 2052 and 1422 MPa, respectively. Various quenching methods enable multi‐level strength control for the same steel grade, achieving a strength control range of ≈1000 MPa. The microstructure of samples quenched by water, die, and oil is fully martensite, and martensite exhibited block and lath morphology. With the increase of cooling rate, martensite laths become finer and the prior austenite size decreased. The microstructure of air‐cooled samples is martensite, ferrite, and retained austenite. The strengthening mechanisms of different quenched samples are calculated. The results show that dislocation strengthening and precipitation strengthening are the two dominant strengthening mechanisms in 30MnB5NbTi hot stamping steel. Therefore, the properties of hot stamping steel can be improved by changing the cooling rate by designing physical dies.

show abstract

Kinetics of anomalous multi-step formation of lath martensite in steel

Cited by 23 publications

References 55 publications

Martensite Transformation Intergrain and Intragrain Autocatalysis in Fe-Ni alloys

Martensite Transformation Intergrain and Intragrain Autocatalysis in Fe-Ni alloys

Anomalous kinetics of lath martensite formation in stainless steel

Effect of Different Quenching Methods on the Microstructure and Mechanical Properties of 30MnB5NbTi

Contact Info

Product

Resources

About