Lattice parameters of iron-carbon and iron-nitrogen martensites and austenites

Liu, Cheng; Böttger, A.; Keijser, Th.H. de; Mittemeijer, E. J.

doi:10.1016/0956-716x(90)90192-j

Cited by 358 publications

(176 citation statements)

References 9 publications

Supporting

Mentioning

155

Contrasting

Unclassified

Order By: Relevance

“…Ridley et al 1) and Cheng et al 2) measured the lattice constant of g-iron using specimens quenched into room temperature. The quenched specimens included unstable phase and had not a few strain by stress.…”

Section: Introductionmentioning

confidence: 99%

Lattice Constant of Iron and Austenite Including Its Supersaturation Phase of Carbon

Seki

Nagata

2005

ISIJ Int.

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Lattice Constant of Iron and Austenite Including Its Supersaturation Phase of Carbon

Seki

Nagata

2005

ISIJ Int.

View full text Add to dashboard Cite

“…We doubt that damping could be caused by interstitial contamination in the metal by C or N atoms; the small change in x-ray lattice parameter compared to that of bulk bcc Fe indicates a concentration of C or N of less than 0.2 at. % [19]. It might be argued that some damping could originate with internal stresses.…”

mentioning

confidence: 99%

Phonons in Nanocrystalline57Fe

et al. 1997

View full text Add to dashboard Cite

We measured the phonon density of states (DOS) of nanocrystalline Fe by resonant inelastic nuclear g-ray scattering. The nanophase material shows large distortions in its phonon DOS. We attribute the high energy distortion to lifetime broadening. A damped harmonic oscillator model for the phonons provides a low quality factor, Q u , averaging about 5, but the longitudinal modes may have been broadened most. The nanocrystalline Fe also shows an enhancement in its phonon DOS at energies below 15 meV. The difference in vibrational entropy of the bulk and nanocrystalline Fe was small, owing to competing changes in the nanocrystalline phonon DOS at low and high energies.[ S0031-9007(97) PACS numbers: 76.80. + y, 61.72. -y, 63.20. -e Over the past decade there has been much interest in nanocrystalline materials, generally defined as materials composed of crystallites smaller than 100 nm. Unusual mechanical properties and soft magnetic properties were topics of numerous investigations on metallic nanocrystals [1]. Very recently, neutron inelastic scattering measurements have shown some differences in the phonon density of states (DOS) of nanocrystalline and bulk materials [2-6]. One such effect was an enhancement of the phonon DOS at low energies [3][4][5][6][7]. A broadening of the peak from the longitudinal modes in the phonon DOS was also observed and attributed to the lifetime broadening of phonons in small crystals [5,6]. Unfortunately, it was not possible to measure accurately the shape of the longitudinal peak, owing to statistical and background limitations of the neutron inelastic scattering technique.In this Letter we show how a recently developed experimental technique, resonant inelastic nuclear g-ray scattering [8,9], provides new information on the shape of the phonon DOS of nanocrystalline Fe. In particular, the excellent signal-to-noise ratio of the data makes it possible to examine quantitatively the high energy tail of the phonon DOS in small samples. In our resonant inelastic nuclear g-ray scattering measurements, 14.41 keV g rays were directed onto a foil specimen, and 6.4 keV conversion x-ray radiations from the specimen were detected. This scattering is incoherent, so the data provide information on the velocity-velocity correlation function of individual 57 Fe nuclei. The experiments were performed at the undulator beamline 3-ID at the Advanced Photon Source. A high-heat-load monochromator, which consists of two symmetric silicon (1 1 1) reflections in a nondispersive setting, and a high-resolution, nested monochromator, as described previously [10], were used to provide the 14.413 keV radiation onto the specimen. The highresolution monochromator operates with asymmetric silicon (4 2 2) and symmetric silicon (10 6 4) reflections and produces a constant energy bandwidth of 5.5 meV over the tuning range. The energy of the incident radiation was tuned by rotating the (10 6 4) channel-cut crystal in steps of 2 meV. The photons were incident on the sample at 5 3 10 9

show abstract

“…Few studies can be found in the literature about residual stresses in retained austenite during or after quenching of steel. Several authors describe the residual stress state within retained austenite existing at room temperature as a hydrostatic residual stress state under high compressive stresses [4][5][6]. The reason for this is a very large volume expansion associated with the martensitic transformation (close to 3%).…”

Section: Figure 2: A) Evolution Of Austenite Lattice Parameter Duringmentioning

confidence: 99%

“…In the literature, two different sets of data concerning the evolution of austenite lattice parameter at room temperature as a function of the carbon content can be found: the one based on room temperature measurements after quenching (retained austenite) and the one based either on high temperature measurements of austenite with thermal expansion correction or on Mn-/ Ni-stabilized austenite at RT. From the literature data, equations were developed based on the room temperature measurements (a RT =0.3556 + 0.00443 × % C) and on the high temperature measurements (a stress-free =0.3573 + 0.00327 × % C) with %C in Mass.-% [4]. It can be assumed that difference between the high temperature data and the retained austenite at room temperature should be due to generation of hydrostatic residual stresses caused by the large transformation strain.…”

Section: Figure 2: A) Evolution Of Austenite Lattice Parameter Duringmentioning

confidence: 99%

Effects of Hydrostatic 2nd Kind Residual Stresses and of Carbon Partitioning During Martensitic Quenching of Low Alloy Steel

Épp

2016

Residual Stresses 2016

View full text Add to dashboard Cite

Abstract. In situ X-ray diffraction measurements were performed at the ESRF in Grenoble, France during quenching of two steel grades: the ball bearing steel AISI52100 and the case hardening steel AISI5120. Diffraction frames were recorded during the complete heat treatment cycles and analyzed in order to determine the temperature-and time-dependent evolution of phase contents and lattice parameters. In the case of the AISI52100 with austenitizing at high temperature, the generation of high compressive hydrostatic stresses of 2 nd kind was determined. In the case hardening steel, the dominating effect is a carbon enrichment of the austenite accompanied by the generation of compressive stresses. For the ball bearing steel austenitized at low temperature, both effects take place. IntroductionMartensitic transformation in steels has now been investigated for more than 100 years [1] The interest in martensitic transformations is still very high as numerous industrial applications use this transformation to improve wear, mechanical and fatigue properties of parts in engineering components [2]. Moreover, new interest on fundamentals of martensitic transformations appeared in the last decades with the development of computer simulation, where kinetics, distortions and other phenomena have to be well described to reach reliable simulation results.In situ X-ray diffraction analysis has become a powerful method of materials characterization stimulated by constant advances in instrumentation and data processing. This method allows obtaining time-resolved quantitative information about every single phase present in the investigated material.In the present study, in situ X-ray diffraction experiments were performed with synchrotron X-ray radiation at ESRF on beamline ID11 during heat treatment of two low alloy steels with varying parameters. Different carbon contents in solution were set in hypereutectoid steel, leading to changing behaviors during quenching. Diffraction frames were recorded during the complete heat treatment cycles and analyzed to determine the temperature-and time-dependent evolution of phase contents and lattice parameters. Based on the data, different effects were investigated during quenching.

show abstract

Lattice parameters of iron-carbon and iron-nitrogen martensites and austenites

Cited by 358 publications

References 9 publications

Lattice Constant of Iron and Austenite Including Its Supersaturation Phase of Carbon

Lattice Constant of Iron and Austenite Including Its Supersaturation Phase of Carbon

Phonons in Nanocrystalline57Fe

Effects of Hydrostatic 2nd Kind Residual Stresses and of Carbon Partitioning During Martensitic Quenching of Low Alloy Steel

Contact Info

Product

Resources

About