Characterization of plasticity-induced martensite formation during fatigue of austenitic steel

Bässler, Hans-Jürgen; Eifler, Dietmar

doi:10.1016/b978-008043326-4/50050-7

Cited by 7 publications

(6 citation statements)

References 3 publications

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“…7 cyclic deformation curves (a), the cycle-dependent development of α 0 -martensite fraction (b) and the relation between stress amplitude and α 0 -martensite fraction (c) are shown for a plastic strain amplitude of e a,p = 4 Á 10 -3 . The r a , N-curves are determined by cyclic hardening pro-cesses due to a change of the dislocation density in the austenite [2] as well as the increase of the number of stacking faults [3] primarily during the first 200 cycles (a) and essentially by plasticity-induced austenite -martensite transformation (b) during the further fatigue process. The α 0 -martensite volume fraction increases continuously with increasing cumulative plastic strain and reaches higher values at higher loading amplitudes (Fig.…”

Section: Resultsmentioning

confidence: 99%

Investigation and modelling of theplasticity-induced martensite formation in metastable austenites

Smaga

Walther

Eifler

2006

International Journal of Materials Research

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Mechanical stress -strain hysteresis, temperature and magnetic measurements were performed for the detailed characterisation of the cyclic deformation behaviour of metastable austenitic steels with particular attention to plasticity-induced martensite formation. Specimens of AISI 304, AISI 321 and AISI 348 stainless steels were investigated under plastic strain control at ambient temperature. On the basis of comprehensive experimental data, a model was developed for the description of the plasticity-induced martensite formation in metastable austenites under cyclic loading. The process of martensite formation was described as a function of the cumulative plastic strain and the cumulative strain energy density.Keywords: Cyclic deformation behaviour; Mechanical stress -strain hysteresis, temperature and magnetic measurements; Metastable austenitic steels; Plasticity-induced martensite formation; Modelling of martensite formation Int.

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Section: Resultsmentioning

confidence: 99%

Investigation and modelling of theplasticity-induced martensite formation in metastable austenites

Smaga

Walther

Eifler

2006

International Journal of Materials Research

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“…They assumed that nucleation occurred preferentially at intersecting shear bands. Baundry, 4 Bayerlein, 5 Bassler 6 and others investigated martensite formation under cyclic loading conditions. The influence of the load amplitude and the temperature on the volume fraction of martensite was qualitatively described.…”

Section: Introductionmentioning

confidence: 99%

Monitoring fatigue degradation in austenitic stainless steels

Kalkhof

Große

Niffenegger

et al. 2004

Fatigue Fract Eng Mat Struct

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A B S T R A C T During cyclic loading of austenitic stainless steel, microstructural changes occurred, which affected both mechanical and physical properties. For certain steels, a strain-induced martensitic phase transformation was observed. The investigations showed that for the given material and loading conditions the volume fraction of martensite depended on the cycle number, temperature and initial material state. It was found that the martensite content continuously increased with the cycle number. Therefore, the volume fraction of martensite was used for indication of the fatigue usage. The temperature dependence of the martensite formation was described by a Boltzmann function. The martensite content decreased with increasing temperature. Two different heats of the austenitic stainless steel X6CrNiTi18-10 (AISI 321, DIN 1.4541) were investigated. The martensite formation rate was much higher for the cold-worked material than for the solution-annealed one. All applied techniques, neutron diffraction and advanced magnetic methods allowed the detection of martensite in the differently fatigued specimens.Keywords austenitic stainless steel; lifetime extension; low-cycle fatigue; non-destructive testing; nuclear safety; strain-induced martensite. N O M E N C L A T U R Ea = lattice constant A, B, t o = parameters of the Boltzmann function for data analysis bcc = body centred cubic lattice B x , B z = axial and radial components of the magnetic induction c α , (c α ) o = volume fraction of martensite for the fatigued (strained) and initial material state D = usage factor, ratio of the applied cycle number to an averaged cycle number representing the technical crack initiation DMC = neutron diffractometer for cold neutrons used for determination of the volume fraction of martensite EC = eddy current fcc = face centred cubic lattice FERROMASTER ® = device for measurement of the magnetic susceptibility or permeability FLUXGATE = high sensitive magnetometer for measuring the remaining magnetic induction (remanence) GMR = Giant Magneto-Resistance sensor used for eddy current impedance measurement with high local resolution ICP-OES = inductive coupled plasma emission photometry used for the determination of the chemical composition of steels LCF = low-cycle fatigue M d = starting temperature for the strain-induced martensite formation

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“…Besides characteristic changes in the dislocation structure and/or density by cyclic loading in metastable austenitic steels at temperatures up to the M d -temperature (martensite deformation temperature) phase transformation from austenite into martensite and at higher temperatures dynamic strain aging (DSA) occur [1][2][3][4][5][6][7]. The phase transformation from paramagnetic austenite into ferromagnetic α´-martensite causes cyclic hardening as well as a change in the magnetic properties [7].…”

Section: Introductionmentioning

confidence: 99%

“…At higher temperatures, in a defined temperature range the cyclic deformation behavior depends on the chemical composition and plastic deformation rate and becomes visible by the DSA-effect. Both effects significantly influence the cyclic deformation behaviour and consequently the fatigue properties of austenitic steels [1][2][3][4][5][6][7]. Detailed analysis of the deformation-induced martensite formation and the DSA-effect are fundamental requirements for optimized applications of metastable austenitic steels in nuclear, power plants and chemical industry.…”

Section: Introductionmentioning

confidence: 99%

Cyclic Deformation Behavior of Austenitic Steels in the Temperature Range -60°C ≤T ≤550°C

Smaga

Hahnenberger

Sorich

et al. 2011

KEM

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In this investigation specimens of the austenitic steels AISI 304, AISI 321 and AISI 348 were investigated in fatigue tests in the temperature range -60°C ≤ T ≤ 550°C. A detailed microstructure-based characterization of the cyclic deformation behavior of austenitic steels was performed by means of stress-strain hysteresis, electrical resistance and magnetic measurements. Up to ambient temperature the occurring deformation induced martensite formation was measured in-situ with a ferritescope during cyclic loading. The temperature range for dynamic strain aging was reliably identified by means of a temperature increase fatigue test with one single specimen.

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Characterization of plasticity-induced martensite formation during fatigue of austenitic steel

Cited by 7 publications

References 3 publications

Investigation and modelling of theplasticity-induced martensite formation in metastable austenites

Investigation and modelling of theplasticity-induced martensite formation in metastable austenites

Monitoring fatigue degradation in austenitic stainless steels

Cyclic Deformation Behavior of Austenitic Steels in the Temperature Range -60°C ≤T ≤550°C

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