scholarly journals Effect of the γ→ε Phase Transition on Transformation-Induced Plasticity (TRIP) of Nickel-Free High Nitrogen Steel at Low Temperatures

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 710
Author(s):  
Natalia Narkevich ◽  
Yevgeny Deryugin ◽  
Yury Mironov

The deformation behavior, mechanical properties, and microstructure of Fe-Cr-Mn-0.53%N austenitic stainless steel were studied at a temperature range of 77 up to 293 K. The dynamics of the steel elongation were non-monotonic with a maximum at 240–273 K, when peaks of both static atom displacements from their equilibrium positions in austenite and residual stresses in the tensile load direction were observed. The results of X-ray diffraction analysis confirmed that the only stress-induced γ→ε-martensite transformation occurred upon deformation (no traces of the γ→α′ one was found). In this case, the volume fraction of ε-martensite was about 2–3%. These transformation-induced plasticity (TRIP) patterns were discussed in terms of changes in the phase composition of steel as the root cause.

2011 ◽  
Vol 681 ◽  
pp. 516-521
Author(s):  
Ru Lin Peng ◽  
Guo Cai Chai ◽  
Tobias Stein ◽  
Thorsten Manns ◽  
Sten Johansson

The deformation behaviour of four super duplex stainless steels of the grade SAF 2507 (UNS S32750) were studied by X-ray diffraction experiment with in-situ uniaxial tensile load. The steels had different nitrogen contents, between 0.2 and 0.33%, and/or different volume fractions of the ferrite, between 37% and 49%, in balance with austenite. The development of phase-specific stresses under external loading up to over 10% tensile strain was followed. The X-ray diffraction measurements revealed that load partitioning between the phases changed with increasing applied load, as the ferrite and austenite exhibited different deformation hardening behaviours. At the onset of macroscopic yielding and low plastic strains, a load transfer from γ to α occurred due to higher yield strength and strain hardening rate of the ferrite but vice versa at larger plastic strains when the austenite hardened more rapidly than the ferrite. It was also concluded that both the yield and tensile strengthen of the steels increased with increasing nitrogen content due to increased strengthen of the austenite by additional solid solution hardening, whereas a higher volume fraction of austenite contributed to higher tensile strength.


Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7160
Author(s):  
Jae-Hwan Kim ◽  
Myong-Soo Lee ◽  
Jong-Sig Kim

The relationship between the tensile properties and damping capacity of fatigue-damaged Fe-22%Mn-12%Cr-4%Co-3%Ni-2%Si alloy under various magnitudes of fatigue stress was investigated. Analytical results show that α′- and ε-martensite were formed due to fatigue stress. The formed α′- and ε-martensite followed a specific orientation and surface relief and intersected with each other. TEM observation and pattern analysis reveal that both α′- and ε-martensites formed on the austenite. As a result of X-ray diffraction, with an increase in fatigue stress, the volume fractions of α′- and ε-martensite were increased, and the increasing rate of the volume fraction of α′-martensite was higher than that of the ε-martensite. As the fatigue stress increased, the tensile strength and damping capacity increased, but the elongation decreased. Besides, as the strength increased and the elongation decreased, the damping capacity decreased. This result is inconsistent with the general tendency for metals but similar to that of alloys undergoing deformation-induced martensite transformation.


2016 ◽  
Vol 30 (26) ◽  
pp. 1650328
Author(s):  
Yan Dong ◽  
Aimin Sun ◽  
Bin Xu ◽  
Hongtao Zhang ◽  
Meng Zhang

In this paper, the effect of tiny Y2O3 addition in (Bi,[Formula: see text]Pb)-2223 superconductor prepared by solid state reaction technique was studied. The properties of samples have been investigated via X-ray diffraction (XRD), resistance–temperature ([Formula: see text]–[Formula: see text]) curve, scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). XRD data indicated that all samples are multiphase and the major phases are high-temperature phases and low-temperature phases. The volume fraction of (Bi,[Formula: see text]Pb)-2223 is not great change with tiny Y2O3 addition. All samples exhibit superconducting phase with the critical transition temperature and one-step transition, however, the transition width was decreased with the Y2O3 addition up to 0.04 wt.% and sharp increased with the excessive oxide addition. SEM pictures show that the Y2O3 appeared on the flake-type grains surface obviously, but the number and size of the hole between grains are decreased in the 0.04 wt.% addition.


2020 ◽  
pp. 554-559
Author(s):  
V.E. Arkhipov ◽  
T.I. Murav’eva ◽  
M.S. Pugachev ◽  
I.V. Shkaley

The results of effect of deposition temperature and the overlap coefficient on the formation of the phase composition of coating based on Cu, Zn and Al2O3 particles mixture applied by cold gas-dynamic deposition are presented. Using X-ray diffraction and X-ray spectral analysis, it is shown that when using the 55 % overlap coefficient electron-type compound based on CuZn3 (ε-phase) is formed in the coating, the mass fraction of which increases to 11.4 % with increase in the deposition temperature. Deposition with 64 % overlap coefficient is accompanied by the formation not only of the ε-phase, but of electron-type compound based on Cu5Zn8 (γ-phase), the mass fraction of which increases to 33 % at temperature of 450 °C. In the process of coating deposition, the predominant diffusion copper into zinc takes place; the calculations show high value of the diffusion coefficient copper — 1,56•10–13 m2 /s.


2011 ◽  
Vol 239-242 ◽  
pp. 1092-1095
Author(s):  
Xu Tao Gao ◽  
Ai Min Zhao ◽  
Zheng Zhi Zhao ◽  
Ming Ming Zhang ◽  
Di Tang

By means of optical microscopy(OM), scanning electron microscopy(SEM),X-ray diffraction(XRD),And tensile test, Mechanical Properties of hot rolled transformation -induced plasticity (TRIP) steels which were prepared through three different coiling temperature was investigated. Result reveals that the formability index of the experimental steel descends when the coiling temperature becomes low. Different coiling temperature has greater impact on retained austenite. Amount and carbon content of retained austenite in the experimental steel get less with lower coiling temperature.


1994 ◽  
Vol 08 (19) ◽  
pp. 1175-1183 ◽  
Author(s):  
G. RAVI CHANDRA ◽  
B. GOPALA KRISHNA ◽  
S. V. SURYANARAYANA ◽  
T. S. N. MURTHY

The effect of the addition of Sn on the superconducting properties of the Bi 1.7 Pb 0.3 Sr 2 Ca 2 Cu 3 O y system as functions of Sn concentration and heat treatment has been studied by dc electrical resistance, ac magnetic susceptibility, and X-ray diffraction. Tin addition suppresses the volume fraction of the high T c phase. Samples with Sn > 0.1 show metallic behavior up to LNT. The formation of the Ca 2 PbO 4 phase is promoted by Sn. This depletes the amount of Pb and Ca necessary for the formation of the 2223 phase, thus reducing the volume fraction of the 2223 phase. It is possible that at least a small fraction of tin substitutes some of the cationic sites of the starting composition. The results of the different measurements are presented.


2010 ◽  
Vol 654-656 ◽  
pp. 819-822
Author(s):  
Genki Kikuchi ◽  
Hiroshi Izui ◽  
Yuya Takahashi ◽  
Shota Fujino

In this study, we focused on the sintering performance of Ti-4.5Al-3V-2Mo-2Fe (SP-700) and mechanical properties of SP-700 reinforced with titanium boride (TiB/SP-700) fabricated by spark plasma sintering (SPS). TiB whiskers formed in titanium by a solid-state reaction of titanium and TiB2 particles were analyzed with scanning electron microscopy and X-ray diffraction. The TiB/SP-700 was sintered at temperatures of 1073, 1173, and 1273 K and a pressure of 70 MPa for 10, 30, and 50 min. The volume fraction of TiB ranged from 1.7 vol.% to 19.9 vol.%. Tensile tests of TiB/SP-700 were conducted at room temperature, and the effect of TiB volume fraction on the tensile properties was investigated.


2020 ◽  
Vol 90 (5) ◽  
pp. 795
Author(s):  
Р.В. Селюков ◽  
В.В. Наумов

Textured Pt films with thickness h=20-80 nm were sputter deposited on oxidized c-Si (100) wafers and annealed in vacuum at 500°C/60 min. The thickness dependencies of the crystalline texture parameters and of the fraction of crystalline phase δ are obtained for as-deposited and annealed films using X-ray diffraction. The determination of δ in textured films is carried out by the new method based on rocking curve analysis. It is found that annealing leads to the texture improvement and to the increasing of δ for all h. The less h, the stronger effects of texture improvement and of δ increasing. These results are explained by the annealing-induced formation of large secondary grains whose volume fraction increases as h decreases. The inhomogeneity of the depth distributions of texture parameters and of δ are investigated for the as-deposited Pt films.


2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Moukrane Dehmas ◽  
Jacques Lacaze ◽  
Aliou Niang ◽  
Bernard Viguier

Inconel 718 is widely used because of its ability to retain strength at up to 650∘C for long periods of time through coherent metastable Ni3Nb precipitation associated with a smaller volume fraction of Ni3Al precipitates. At very long ageing times at service temperature, decomposes to the stable Ni3Nb phase. This latter phase is also present above the solvus and is used for grain control during forging of alloy 718. While most works available on precipitation have been performed at temperatures below the solvus, it appeared of interest to also investigate the case where phase precipitates directly from the fcc matrix free of precipitates. This was studied by X-ray diffraction and transmission electron microscopy (TEM). TEM observations confirmed the presence of rotation-ordered domains in plates, and some unexpected contrast could be explained by double diffraction due to overlapping phases.


1999 ◽  
Vol 557 ◽  
Author(s):  
D. Peiró ◽  
C. Voz ◽  
J. Bertomeu ◽  
J. Andreu ◽  
E. Martínez ◽  
...  

AbstractHydrogenated microcrystalline silicon films have been obtained by hot-wire chemical vapor deposition (HWCVD) in a silane and hydrogen mixture at low pressure (<5 × 10-2 mbar). The structure of the samples and the residual stress were characterised by X- ray diffraction (XRD). Raman spectroscopy was used to estimate the volume fraction of the crystalline phase, which is in the range of 86 % to 98%. The stress values range between 150 and -140 MPa. The mechanical properties were studied by nanoindentation. Unlike monocrystalline wafers, there is no evidence of abrupt changes in the force-penetration plot, which have been attributed to a pressure-induced phase transition. The hardness was 12.5 GPa for the best samples, which is close to that obtained for silicon wafers.


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