共查询到20条相似文献,搜索用时 31 毫秒
1.
A weldable corrosion-resistant alloy based on the Al - Zn - Mg system has been developed. The alloy has high strength characteristics
(σr ≥ 500 MPa and σ0.2 ≥ 450 MPa) and is well weldable (the factor of weld concavity is 0.8 – 0.95). The substrate metal and welded joints of this
metal are characterized by high corrosion resistance, good ductility and fracture toughness, and high fatigue resistance.
The alloys and the process of its production are based on known scientific achievements of the All-Russia Institute of Light
Alloys (VILS) in the field of alloys of the Al - Zn - Mg system and in the field of alloying of aluminum alloys with scandium.
__________
Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 30 – 35, August, 2005. 相似文献
2.
L. F. Kozin S. V. Volkov S. G. Goncharenko V. V. Permyakov B. I. Danil’tsev 《Protection of Metals and Physical Chemistry of Surfaces》2011,47(2):171-180
The kinetics and mechanism of interaction of aluminum and magnesium of an Al-Mg-Bi ternary system with water were obtained
using the method of high-temperature volumetry at high pressures and temperatures of 225–325°C. The kinetic parameters of
the reaction, i.e., the rate constant, activation energy, and degree of conversion, were calculated and the mechanism of corrosion
dissolution of activated by bismuth aluminum and magnesium in water with the release of hydrogen at high rates was suggested.
The kinetic parameters during the interaction of aluminum activated by bismuth and magnesium in boehmite (AlOOH), and magnesium
hydroxide (Mg(OH)2) with water with the release of hydrogen at a rate of 3196–4033 l/(m2 min) in the investigated temperature range were determined. The nanostructured particles of Al-Mg-Bi alloys were detected
using a JSM6490 LV electron microscope (Japan). 相似文献
3.
Cast heat-resisting alloys containing 45 or 60 wt% nickel were isothermally carburized in flowing gas mixtures of H2–5CH4 (volume percent) at temperatures of 900–1,100 °C, and their performance compared with that of standard commercial grades
containing 30–35% nickel. Chromium-rich M7C3 and M23C6 precipitated internally in all materials, to depths which increased according to parabolic kinetics. Comparison of the rate
constants with those predicted from Wagner’s diffusion theory showed that carbon diffusion through a chromium-depleted alloy
matrix was the rate-controlling process. The 45% nickel alloys carburized more slowly than the 30–35% nickel grades as a result
of decreased carbon solubility and diffusivity at the higher nickel level. The 60% nickel alloys also contained aluminum.
At higher temperatures, diffusion of aluminum to the surface led to A12O3 scale formation and enhanced carburization resistance. The degree of protection obtained depended on alloy aluminum content.
P. Becker—On secondment from Schmidt & Clemens GmbH, Post Fach 1140, 51779 Lindlar, Germany. 相似文献
4.
I. I. Reformatskaya I. G. Rodionova A. N. Podobaev I. I. Ashcheulova E. V. Trofimova 《Protection of Metals》2006,42(6):549-554
A jumpwise improving of the passivation ability and pitting-resistance of the Fe-(8–13)% Cr-(0.32–2.7)% Si alloys upon surpassing
the limit of ∼14–15 at % by the chromium and silicon summary concentration is found. It is suggested that the nature of the
critical summary concentration C
Cr + C
Si is identical to that in Fe-Cr binary alloys; it is caused by the silicon building-in to the alloy’s crystal lattice and its
substitution for chromium in the statistical proportion to its atomic part in alloys. When the summary concentration C
Cr + C
Si approaches ∼14–15 at %, each elementary cell in the Fe bcc lattice must necessarily contain either a Cr atom or the proportional
number of Si atoms. The improved passivation ability and pitting-resistance of the Fe-Cr-Si alloy, compared with the Fe-Cr
alloys, is explained by the fayalite formation at the alloy surface.
Original Russian Text ? I.I. Reformatskaya, I.G. Rodionova, A.N. Podobaev, I.I. Ashcheulova, E.V. Trofimova, 2006, published
in Zashchita Metallov, 2006, Vol. 42, No. 6, pp. 591–597. 相似文献
5.
Based on the model taking into account the appearance of a morphological instability and the evolution of a surface with time
during the selective anodic dissolution of a homogeneous A-B alloy with the predominant content of the electrochemically negative
metal A, equations for the critical potential E
cr and overpotential ηcr of the surface development are derived. Criteria of the nature of chemical hindrances of the selective dissolution in the
over-critical range are formulated. The E
cr and ηcr values corresponding to the breakage of the morphological stability of the A-B alloy surface (with the atomic silver part
X
Ag = 0.65 to 0.95) in an acidic nitrate solution containing diverse amounts of silver ions (10−4 to 10−2 M) are experimentally found. The character of the effect of the atomic gold content in the alloy and the concentration of
silver ions in the solution on ηcr and E
cr values of the alloys is determined. The nature of the kinetic limitations of the selective dissolution in the over-critical
potential range is clarified.
Original Russian Text ? A.V. Vvedenskii, O.V. Koroleva, O.A. Kozaderov, 2008, published in Zashchita Metallov, 2008, Vol.
44, No. 1, pp. 28–37. 相似文献
6.
Scanning tunnel microscopy (STM) and scanning tunnel spectroscopy (STS) are used in studying highly pure iron and chromium
and Fe-x%Cr (2.4 ≤ x ≤ 60 wt %) alloys at the air boundary, as well as some of the alloys in 0.01 N H2SO4. The obtained probability coefficients (α) of the electron tunnel transfer from a specimen to the needle and the slopes (β)
of the logarithmic U
t
/log (I
t
) dependences as functions of the chromium content in Fe-Cr alloys confirm the critical compositions of the alloys containing
∼6.5 and 10–13% chromium, which is in accord with the results of the steady-state and transient electrochemical measurements.
A correlation between these critical compositions of the alloys and sharp changes in the histograms of α and β values is observed.
Pronounced extreme properties of the Fe-25.2% Cr alloy surface, which corresponds to the inclusion of Cr atoms in tetrahedral
voids of the alloy crystal lattice, are noticed.
Original Russian Text ? E.V. Trofimova, E.V. Kasatkin, I.I. Reformatskaya, 2006, published in Zashchita Metallov, 2006, Vol.
42, No. 3, pp. 245–255.
The work was financially supported by the Russian Foundation for Basic Research, project no. 04-03-32337. 相似文献
7.
The oxidation of three Ni–xCr–10Al alloys with a constant Al content of 10 at% and containing 3, 5, and 10 at% Cr was investigated at 900–1000°C in 1 atm of pure oxygen and compared to the behavior of Ni–10Al. At both temperatures, an external NiO scale overlying a zone of internal-oxide precipitates formed on Ni–10Al and Ni–3Cr–10Al: in addition, a discontinuous Al2O3 layer formed at the front of the internal oxidation for Ni–3Cr–10Al. An exclusive external scale of Al2O3 formed at most places on Ni–5Cr–10Al at 900°C, while, at some sites, the same alloy formed an outer NiO layer overlying an internal oxidation zone. The scales formed on Ni–5Cr–10Al at 1000°C were complex, but eventually a protective Al2O3 layer developed either at the alloy surface or beneath a region containing a mixture of different oxides. Finally, an exclusive external Al2O3 layer formed on Ni–10Cr–10Al at both temperatures. Thus, the addition of sufficient chromium to Ni–10Al produced a classical third-element effect, inducing the transition between internal and external oxidation of aluminum under a constant Al content. A possible mechanism for the effect of chromium on the oxidation of Ni–10Al is discussed on the basis of an extension to ternary alloys of a criterion first proposed by Wagner for the transition between internal and external oxidation of the most-reactive component in binary alloys. 相似文献
8.
V. Burokas A. Martushene A. Ruchinskene A. Sudavichyus G. Bikulchyus 《Protection of Metals》2006,42(4):339-344
Amorphous phosphating of aluminum and its alloys AДH, Д1, and Д16 is studied. It is found that uniform coatings are deposited
at pH 4.5 at a temperature of 50°C from the solution containing MoO
4
2−
promoting ions. By using the x-ray photoelectron spectroscopy, it is shown that phosphates of aluminum and Mo(IV, V) are
the predominant components of phosphate coating. By the “thin layer” method, it is found that, in the near-surface layer,
alkalization of solution takes place depending on the initial pH value. The dependence pHdep = pHin ± 0.3 is linear. Phosphate coatings, which are deposited in the solution pretreated with magnetic field (MF), differ in their
properties from the coatings obtained by the conventional procedure. MF can increase or decrease the corrosion resistance
of phosphate coating depending on the aluminum alloy.
Original Russian Text ? V. Burokas, A. Martushene, A. Ruchinskene, A. Sudavichyus, G. Bikul’chyus, 2006, published in Zashchita
Metallov, 2006, Vol. 42, No. 4, pp. 373–378. 相似文献
9.
IncoMAPAl—9052合金在3.5%NaCl溶液中的应力腐蚀行为 总被引:1,自引:0,他引:1
胡津 《中国腐蚀与防护学报》1998,18(2):136-140
采用双悬臂梁试样,实验研究了IncoMAP Al-9052合金在3.5%NaCl溶液中的应力腐蚀开裂(SCC)行为。结果表明该种合金的裂纹扩展机制有别于常规的铝合金。其初期阶段的裂纹扩展过程可划分为三个阶段,在每一阶段的裂纹扩展机制可能是不同的,但其裂纹扩展的主要机制为氢脆。 相似文献
10.
J. Andrieux O. Dezellus F. Bosselet J. C. Viala 《Journal of Phase Equilibria and Diffusion》2009,30(1):40-45
Reaction zones formed at 790 °C between solid titanium and liquid Ag-Cu eutectic alloys (pure and Ti-saturated) have been
characterized. When pure Ag-Cu eutectic alloy with 40 at.% Cu is used, the interface reaction layer sequence is: αTi/Ti2Cu/TiCu/Ti3Cu4/TiCu4/L. Because of the fast dissolution rate of Ti in the alloy, the reaction zone remains very thin (3-6 μm) whatever the reaction
time. When the Ag-Cu eutectic alloy is saturated in titanium, dissolution no longer proceeds and a thicker reaction zone with
a more complex layer sequence grows as the reaction time increases. Four elementary chemical interaction processes have been
identified in addition to Ti dissolution in the liquid alloy. These are growth of reaction layers on Ti by solid state diffusion,
nucleation and growth from the liquid of TiCu4, isothermal solidification of silver and, finally, chemical conversion of the Cu-Ti compounds by reaction-diffusion in the
solid state. A mechanism combining these processes is proposed to account for the constitution of Ti/Ag-Cu/Ti joints brazed
at 780-800 °C. 相似文献
11.
The influence of pre-oxidation on the corrosion and mechanical strength of Fe–25Cr and Fe–25Cr–20Ni alloys was investigated in N2–0.1SO2 at 973 K with and without mechanical loadings. About 0.1μm-thick Cr2O3 scales formed on the Fe–25Cr alloy by pre-oxidation in Ar. However, spinel oxides of (Fe,Cr)3O4 remained on the Cr2O3 and voids formed at the oxide/metal interface on Fe–25Cr–20Ni after pre-oxidation in Ar. The preformed oxides are very effective in preventing corrosion of the alloy surfaces. The preformed oxides are also beneficial to increase the strength of the alloys in corrosive environments. The effects of pre-oxidation on Fe–25Cr are stronger than those of Fe–25Cr–20Ni due to the different characteristics of the preformed oxides. 相似文献
12.
I. V. Oryshich 《Protection of Metals》2006,42(6):596-600
High-temperature chloride corrosion (ChC) of ЭИ827 and BЖ-85 nickel alloys was investigated in a temperature range of 773 to 1173 K and exposure time of 1 to 50 h
in the MgCl2-KCl-NaCl ternary eutectic and oxidation in air (at 873 to 1273 K for 500 h). The ChC is intergranular, intensely develops
starting from a temperature of 973 K, and results in softening due to the strong extraction of chromium and aluminum from
the base alloy. Other things being equal, the ChC rate exceeds the oxidation rate in air by two to three orders of magnitude.
Original Russian Text ? I.V. Oryshich, 2006, published in Zashchita Metallov, 2006, Vol. 42, No. 6, pp. 640–644. 相似文献
13.
M. P. Brady B. A. Pint Z. G. Lu J. H. Zhu C. E. Milliken E. D. Kreidler L. Miller T. R. Armstrong L. R. Walker 《Oxidation of Metals》2006,65(3-4):237-261
The goal of this paper was to determine if NiO-forming alloys are a viable alternative to Cr2O3-forming alloys for solid-oxide fuel-cell (SOFC) metallic interconnects. The oxide-scale growth kinetics and electrical properties of a series of Li- and Y2O3-alloyed, NiO-forming Ni-base alloys and La-, Mn-, and Ti-alloyed Fe–18Cr–9W and Fe–25Cr base ferritic Cr2O3-forming alloys were evaluated. The addition of Y2O3 and Li reduced the NiO scale growth rate and increased its electrical conductivity. The area-specific-resistance (ASR) values were comparable to those of the best (lowest ASR) ferritic alloys examined. Oxidation of the ferritic alloys at 800°C in air and air+10% H2O (water vapor) indicated that Mn additions resulted in faster oxidation kinetics/thicker oxide scales, but also lower oxide scale ASRs. Relative in-cell performance in model SOFC stacks operated at 850°C indicated a 60–80% reduction in ASR by Ni+Y2O3, Ni+Y2O3, Li, and Fe–25Cr+La,Mn,Ti interconnects over those made from a baseline, commercial Cr2O3-forming alloy. Collectively, these results indicate that NiO-forming alloys show potential for use as metallic interconnects. 相似文献
14.
We have proposed new hydrogen absorbing alloys of the ‘Laves phase related BCC solid solution alloy’, the hydrogen capacity
of which reaches almost double that of conventional rare-earth based AB5 alloys. We have reported the hydrogen absorbing properties of Ti−V−Mn, Ti−V−Cr and T−V−Mn−Cr alloys. It has been accepted
that the crystal structural change of BCC hydrogen absorbing alloys is the same as that of V metal. The mono-hydride (H/M=1)
of V metal has a BCT structure and the di-hydride (H/M=2) has an FCC structure. However, we recently found that the Ti−V−Mn
alloy shows different behaviors in phase transformation with hydrogenation to V metal. We found three hydride phases with
a BCC, a deformed FCC and an FCC structure in the Ti−V−Mn solid solution alloy-H2 system. The deformed FCC hydride phase has not yet to our knowledge been reported. The lattice constant of the deformed FCC
was 0.407 nm, one axis of which is reduced by about 4%. Its single-phase region appeared at a hydrogen content between 0.8
H/M and 1.0 H/M in absorption at 298 K. The lower plateau observed due to formation of the deformed FCC hydride phase gives
an increase of effective hydrogen capacity by decreasing hydrogen remaining in the alloy in the desorption process.
This article based on a presentation made in the symposium “The 2nd KIM-JIM Joint Symposium: Hydrogen Absorbing Materials”,
held at Hanyang University, Seoul, Korea, October 27–28, 2000 under the auspices of The Korean Institute of Metals and Materials
and The Japan Institute of Metals. 相似文献
15.
钛合金广泛应用于军事航空领域 ,但是一些钛合金在焊接条件下 ,焊缝会产生氢致延迟裂纹 ,其致裂机理尚不十分清楚。通过充氢CT(Compacttension)试件的恒载拉伸试验 ,研究了氢浓度对Ti5 5合金电子束焊缝裂纹尖端应力强度因子门槛值Kth及裂纹扩展速率da/dt的影响规律 ,分析了氢致延迟裂纹扩展的机理。结果表明 ,氢在Ti5 5合金焊缝中的固溶度约为 79× 10 -4%。当充氢浓度C0 低于 79× 10 -4%时 ,随着焊缝氢浓度C0 的增大 ,裂纹开始扩展的应力强度因子门槛值Kth迅速减小 ,而裂纹扩展速率da/dt随着C0 的增大而增大 ;C0 为 79× 10 -4%时 ,Kth为最小值并呈恒值特征。裂纹尖端应力场诱导氢原子扩散导致氢化物TiH2 析出是Ti5 5合金电子束焊缝氢致延迟裂纹扩展的主要机制 相似文献
16.
M. Gögebakan 《Journal of Materials Engineering and Performance》2004,13(4):504-508
This article reports the effect of silicon (Si) addition upon the crystallization behavior and mechanical properties of an
amorphous AlYNi alloy. An amount of 1 at.% Si was added to a base alloy of Al85Y5Ni10 either by substitution for yttrium (Y) to form Al85Y4Ni10Si1, or by substitution for nickel (Ni) to form Al85Y5Ni9Si1. Differential scanning calorimetry (DSC) of all three alloys showed three exothermic peaks. Comparing the peak temperature
for the first exothermic peak, a significant shift occurs toward the lower temperature. This indicates that 1 at.% substitutions
of Y or Ni by Si decreases the stability of the amorphous phase. DSC study of these amorphous alloys during isothermal annealing
at temperatures about 5–15 K lower than their first crystallization peaks showed that the formation of α-Al nanocrystals via
primary crystallization occurred without an incubation period. The Avrami time exponent (n) of the primary crystallization
from the amorphous structure was determined to be 1.00–1.16 using the Johnson-Mehl-Avrami (JMA) analysis. This suggested a
diffusion-controlled growth without nucleation. However, a DSC study of these amorphous alloys during isothermal annealing
at higher temperatures between 585 and 605 K showed a clear incubation period during the formation of the Al3Ni and Al3Y intermetallic phases. An n value of 3.00–3.45 was determined using JMA analysis. This suggested that the transformation reaction involved a decreasing
nucleation rate and interface-controlled growth behavior. The tensile strength σf and Vickers hardness for these amorphous alloys are in the range 1050–1250 MPa and 380–398 diamond pyramid hardness number
(1 diamond pyramid hardness number=1 kg/mm2=9.8 MPa), respectively. 相似文献
17.
The mechanical properties (σb,σ0.2,and δ) and fracture behavior of tensile specimens of the refined A356 alloys were investigated as a function of the addition level of Al-Ti-B master alloy under both as-cast and T6 heat-treated conditions. The results show that as the addition level of Al-5Ti-1B master alloy increases from 0.1 wt.% to 5.0 wt.%,the mechanical properties of refined A356 alloys improve steadily and then decrease slightly under both as-cast and T6 heat-treated conditions. Also,they display exc... 相似文献
18.
A study of the mechanisms of grain refinement in the process of severe plastic deformation of two aluminum alloys, i.e., 2219
bearing nanometric particles of Al3Zr and low-alloy Al-3% Cu, is described. The alloys are deformed by the method of equal channel angular pressing at 250°C
to a maximum strain degree of about 12. The angles of (sub)grain boundaries in alloy 2219 are determined with the help of
transmission electron microscopy by the method of Kikuchi lines. The evolution of the microstructure in alloy Al-3% Cu is
studied with the help of grain-boundary maps obtained by the method of electron back-scattered diffraction.
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Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 14–19, February, 2006. 相似文献
19.
É. I. Illarionov 《Metal Science and Heat Treatment》2000,42(1):31-36
Conclusions
Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 1, pp. 28–33, January, 2000. 相似文献
1. | The data of microstructural, differential, thermal, and x-ray phase analyses and the study of the “composition— properties” dependences have been used for plotting polythermic sections of the Ti−Al−W−Zr phase diagram at a variable content of aluminum and tungsten (0–20%). |
2. | With an increase in the content of one of the elements, i.e., aluminum or tungsten (at a fixed amount of the other elements), the strength characteristics of alloys in the Ti−Zr−Al−W system at room and high (600–800°C) temperatures increase. The behavior of these curves changes when the aluminum content exceeds 9%; they become horizontal at 600 and 700°C and drop markedly at 800°C and at room temperature. |
3. | The plasticity characteristics of the alloys largely depend on their phase composition. At room temperature the values of δ and ψ of the alloy bearing 6% Al and 6% W drop jumpwise. The specific elongation decreases substantially at 600–800°C in the case of alloying with tungsten and aluminum, and the specific reduction of area decreases substantially in alloys with an aluminum additive. At 7–10% W, the value of ψ is maximum (ψ≅100%) at 700–800°C and attains almost 70% at 600°C. |
20.
V. M. Imayev R. M. Imayev T. G. Khismatullin 《The Physics of Metals and Metallography》2008,105(5):484-490
A new approach to obtaining fine-grained structure in intermetallic-compound alloys such as γ-TiAl + α2-Ti3Al has been suggested. This approach is based on the use of alloys that solidify as the β phase, which contain β-stabilizing additives such as Nb and Mo and are characterized by the small size of crystallites already in the cast state; in these alloys, a simple heat treatment makes it possible to substantially decrease the fraction of the lamellar component and to increase the content of the β(B2) phase. It is shown on the example of the Ti-43Al-7(Nb,Mo)-0.2B (at %) alloy that this heat treatment ensures superplastic properties in the material in the temperature range of T = 1050–1130°C at a deformation rate $ \dot \varepsilon A new approach to obtaining fine-grained structure in intermetallic-compound alloys such as γ-TiAl + α2-Ti3Al has been suggested. This approach is based on the use of alloys that solidify as the β phase, which contain β-stabilizing
additives such as Nb and Mo and are characterized by the small size of crystallites already in the cast state; in these alloys,
a simple heat treatment makes it possible to substantially decrease the fraction of the lamellar component and to increase
the content of the β(B2) phase. It is shown on the example of the Ti-43Al-7(Nb,Mo)-0.2B (at %) alloy that this heat treatment ensures superplastic
properties in the material in the temperature range of T = 1050–1130°C at a deformation rate = 1.7 × 10−4 K−1. Under these temperature-strain-rate conditions, relative elongations such as δ = 160–230% and low flow stresses such as
σ = 36–100 MPa characteristic of superplastic flow have been obtained. It has been shown for the first time for the intermetallic
γ-TiAl + ga2-Ti3Al alloy that a sheet semifinished product cut out from an ingot subjected only to heat treatment can have plasticity acceptable
for press forming.
Original Russian Text ? V.M. Imayev, R.M. Imayev, T.G. Khismatullin, 2008, published in Fizika Metallov i Metallovedenie,
2008, Vol. 105, No. 5, pp. 516–522.
The author is also known by the name Imayev. The name used here is a transliteration under the BSI/ANSI scheme adopted by
this journal.—Ed. 相似文献