共查询到20条相似文献,搜索用时 31 毫秒
1.
Y. G. Tkachenko D. Z. Yurchenko S. V. Satanin O. A. Shevchenko L. M. Murzin 《Powder Metallurgy and Metal Ceramics》1998,37(3-4):165-169
Studies have been made on the structure, phase composition, and strength parameters for ceramics based on AlN containing 5–15
mass % TiO2. The tribotechnical characteristics of these ceramics have been determined under sliding friction conditions at 20–900°C
in air. Quantitative characteristics are proposed for the friction surface as determined by metallographic, microdurometric,
and sclerometric examination of the surfaces produced at various treatment temperatures.
Materials Science Institute, Ukrainian Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 3-4(400),
pp. 43–48, March–April, 1998. 相似文献
2.
P. V. Nazarenko I. E. Polishchuk A. E. Ostranitsa A. Yu. Koval' 《Powder Metallurgy and Metal Ceramics》1999,38(1-2):85-88
The features surface morphology are considered for plasma-sprayed coatings used with various counterbodies under conditions
of boundary friction. The tribotechnical characteristics of the coatings are examined in relation to the structure. There
is found to be a substantial effect from the porosity on the formation of the secondary structures, the changes in topography,
and the changes in elemental composition of the friction surface.
Institute for Problems of Materials Science, Ukraine National Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya,
Nos. 1–2(405), pp. 92–97, January–February, 1999. 相似文献
3.
Yu. G. Tkachenko D. Z. Yurchenko V. K. Sul’zhenko G. S. Oleinik V. M. Vereshchaka 《Powder Metallurgy and Metal Ceramics》2007,46(5-6):254-260
The paper examines three groups of samples based on B4C and B13C2 powders (with additions of Al and Al2O3 in the amount of 2 and 5 wt.%, respectively). It is established that the maximal strength (445 MPa) is characteristic of
the material B13C2 over the whole temperature range. It does not change up to 1600°C. The increase in strength of B4C-based samples is revealed over the range of 1200 to 1600°C, mainly for high-porous materials (10–12%). Presumably, this
is due to the higher relaxation properties of porous material microstructure.
__________
Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 5–6 (455), pp. 60–68, 2007. 相似文献
4.
A. I. Yuga Yu. M. Vasilenkov V. V. Koval'chuk 《Powder Metallurgy and Metal Ceramics》1998,37(7-8):390-393
The paper reports the results of tribotechnical tests of a metal matrix based on a copper-nickel alloy with a tin-lead solid
lubricant additive which contained varying amounts of the ceramic binary alloy B4C+ZrB2. The tests showed that the presence of a refractory phase in the metal matrix greatly enhanced the
Institute for Problems of Materials Science, Ukraine National Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya,
Nos. 7–8(402), pp. 54–58, July–August, 1998. 相似文献
5.
A projection has been constructed for the solidus surface in the Al2O3-ZrO2-Sm2O3 phase diagram on the plane of the concentration triangle, which consists of seven isothermal three-phase fields corresponding
to two nonvariant equilibria of eutectic type and five nonvariant equilibria of peritectic type, and also eight lineated surfaces
for the end of crystallization of the binary eutectics. The highest temperature on the solidus surface is 2710°C, the melting
point of pure ZrO2, while the lowest is 1680°C, the temperature of the triple eutectic Al + F + SA. No ternary phases or appreciable regions
of solid solutions based on the components and the binary compounds are observed. Data on the bounding binary systems, the
liquidus and solidus surfaces have been used to construct the phase-equilibrium (melting) diagram together with a reaction
scheme for the equilibrium crystallization of alloys in the Al2O3-ZrO2-Sm2O3 system.
__________
Translated from Poroshkovaya Metallurgiya, Nos. 5–6(449), pp. 56–64, May–June, 2006. 相似文献
6.
The solidus surface for the Al2O3-ZrO2-Er2O3 phase is projected for the first time onto the concentration triangle. It consists of five isothermal three-phase fields
that correspond to four invariant eutectic equilibria, one invariant transformation equilibrium, and six ruled binary eutectic
solidus surfaces. The highest solidus temperature in the system is 2710 °C, which is the melting point of pure ZrO2, and the lowest is 1720°C, which is the melting point of the ternary eutectic AL + F + Er3A5. Neither ternary phases nor visible solid solution areas based on components and binary compounds are found in the system.
Based on the data on bounding binary systems, liquidus, and solidus surfaces, the phase equilibrium diagram and reaction scheme
for equilibrium crystallization of Al2O3-ZrO2-Er2O3 alloys are constructed.
__________
Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 5–6 (455), pp. 74–83, 2007. 相似文献
7.
O. N. Grigor'ev I. A. Podchernyaeva I. P. Neshpor A. D. Panasyuk A. P. Umanskii T. A. Lyudvinskaya O. D. Shcherbina 《Powder Metallurgy and Metal Ceramics》2005,44(7-8):382-388
Based on a study of the structure and composition of the composite ceramic SiC - Al2O3 - ZrO2, its tribomechanical properties and behavior in high-temperature corrosion, we recommend the material for use as sealing
elements and for deposition of wear-resistant and corrosion-resistant coatings. We have studied the formation of gradient
layers when the ceramic surface is modified with refractory titanium compounds TiN - TiB2 (1:1) with an Fe(Ni) - Cr - Al undercoat using concentrated solar radiation and when the steel surface is modified with laser
irradiation of the SiC - Al2O3 - ZrO2 coats. We have shown that laser modification of steel by the silicon carbide-based composite increases its corrosion resistance
by a factor of 4–5 at 800–900 °C.
__________
Translated from Poroshkovaya Metallurgiya, Nos. 7–8(444), pp. 91–99, July–August, 2005. 相似文献
8.
Robert Hansson Peter C. Hayes Evgueni Jak 《Metallurgical and Materials Transactions B》2004,35(4):633-642
The phase equilibria in the Al-Fe-Zn-O system in the range 1250 °C to 1695 °C in air have been experimentally studied using
equilibration and quenching techniques followed by electron probe X-ray microanalysis. The phase diagram of the binary Al2O3-ZnO system and isothermal sections of the Al2O3-“Fe2O3”-ZnO system at 1250 °C, 1400 °C, and 1550 °C have been constructed and reported for the first time. The extents of solid
solutions in the corundum (Al,Fe)2O3, hematite (Fe,Al)2O3, Al2O3*Fe2O3 phase (Al,Fe)2O3, spinel (Al,Fe,Zn)O4, and zincite (Al,Zn,Fe)O primary phase fields have been measured. Corundum, hematite, and Al2O3*Fe2O3 phases dissolve less than 1 mol pct zinc oxide. The limiting compositions of Al2O3*Fe2O3 phase measured in this study at 1400 °C are slightly nonstoichiometric, containing more Al2O3 then previously reported. Spinel forms an extensive solid solution in the Al2O3-“Fe2O3”-ZnO system in air with increasing temperature. Zincite was found to dissolve up to 7 mole pct of aluminum in the presence
of iron at 1550 °C in air. A meta-stable Al2O3-rich phase of the approximate composition Al8FeZnO14+x
was observed at all of the conditions investigated. Aluminum dissolved in the zincite in the presence of iron appears to
suppress the transformation from a round to platelike morphology. 相似文献
9.
The effect of B2O3 on the viscosity and structure in the calcium-aluminate melt flux system containing Na2O was studied. An increase in the B2O3 content at fixed CaO/Al2O3 ratio lowered the viscosity. Higher CaO/Al2O3 ratio at fixed B2O3 content also decreased the viscosity. The alumino-borate structures were confirmed through Fourier transformed infrared (FTIR) and Raman spectroscopy and consisted of [AlO4]-tetrahedral structural units, [BO3]-triangular structural units, and [BO4]-tetrahedral structural units, which could be correlated to the viscosity. At fixed CaO/Al2O3 ratio, B2O3 additions decreased the [AlO4]-tetrahedral structural units and transformed the 3-D network structures such as pentaborate and tetraborate into 2-D network structures of boroxol and boroxyl rings by breaking the bridged oxygen atoms (O0) to produce non-bridged oxygen atoms (O?) leading to a decrease in the molten flux viscosity. At fixed B2O3 contents and higher CaO/Al2O3 ratio, 3-D complex network structures become 3-D simple and 2-D isolated network structures, resulting in lower viscosities. The apparent activation energy for viscous flow varied from 132 to 249 kJ/mol according to the composition of B2O3 and CaO/Al2O3 ratio. 相似文献
10.
Hardening phase/intermetallic matrix pairs are chosen for composite materials (CMs) intended for long-term high-temperature
operation. These materials must have high and stable mechanical properties during a long time at high temperatures and loads.
The compatibility of the physicochemical and mechanical properties of CM components is estimated to choose hardening phase/intermetallic
matrix pairs in which the matrix is represented by an alloy based on NiAl or TiAl monoaluminide and the hardening phase is
a refractory thermodynamically stable oxide of a Group III transition metal M
2O3. The following two schemes are used to perform hardening of a CM with a matrix consisting of a TiAl or NiAl alloy by the
most thermodynamically stable interstitial phases, i.e., refractory oxides, at temperatures higher than the operating temperature
(T
op) of the IMM. The first scheme consists in creating Al2O3/TiAl CMs hardened by continuous single-crystal sapphire fibers using the impregnation of a bundle of single-crystal fibers
with a matrix melt followed by directional solidification. The TiAl-based matrix in these CMs serves as a binder connecting
oxide phase fibers and preventing them from fracture due to high adhesion forces between oxide fibers and the matrix and a
high fiber/matrix interface strength. In the second scheme, Y2O3/NiAl CMs are produced by powder metallurgy methods, which include severe deformation by extrusion accompanied by the formation
of deformation texture and subsequent recrystallization annealing. In these CMs, disperse refractory oxide particles stabilize
grain boundaries in a recrystallized matrix material and lead to the formation of directional structures with coarse elongated
grains and a low fraction of transverse boundaries. Al2O3/TiAl CMs containing 20–25 vol % hardening single-crystal sapphire Al2O3 fibers can operate at temperatures of 1000–1050°C (∼0.7T
m of matrix), which is 250–300°C higher than the maximum values of T
op of a TiAl-based matrix and 400-450°C higher than the maximum values of T
op of a Ti-based matrix. An Y2O3/NiAl composite with a directionally recrystallized structure of a NiAl-based matrix hardened by 2.5 vol % Y{ia2}O3 particles can be recommended for operation at temperatures of 1400–1500°C ((0.8–0.9)T
m of matrix), which are higher by 100–400°C than not only T
op but also T
m of Ni superalloys. 相似文献
11.
Effects of welding and weld heat-affected zone simulation on the microstructure and mechanical behavior of a 2195 aluminum-lithium alloy 总被引:1,自引:0,他引:1
The microstructures, tensile properties, and fatigue properties of a 2195-T8 Al-Li alloy subjected to a weld heat-affected
zone (HAZ) simulation and gas-tungsten-arc (GTA) welding using a 4043 filler metal, with and without a postweld heat treatment,
were studied. The principal strengthening precipitate in the T8 base alloy was the T
1 (Al2CuLi) phase. The HAZ simulation resulted in the dissolution of T
1 precipitates and the formation of T
B(Al7Cu4Li) phase, Guinier-Preston (G–P) zones, and δ′ (Al3Li) particles. When the HAZ simulation was conducted at the highest temperature of 600 °C, microcracks and voids also formed
along the grain boundaries (GBs). In the specimens welded with the 4043 alloy, T (AlLiSi) phase was found to form in the fusion zone (FZ). An elongated T
Bphase and microcracks were observed to occur along the GBs in the HAZ close to the FZ interface. The T
1 phase was not observed in the HAZ. The postweld heat treatment resulted in the spheroidization of primary T phase and the precipitation of small secondary T particles in the FZ, the dissolution of T
B phase, and the reprecipitation of the T
1 phase in the HAZ. Both the HAZ simulation and welding gave rise to a considerable decrease in the hardness, tensile properties,
and fatigue strength. The hardness in the FZ was lower than that in the HAZ. Although the postweld heat treatment improved
both the hardness and tensile properties due to the reprecipitation of T
1 phase in the HAZ and a smaller interparticle spacing in the FZ, no increase in the fatigue strength was observed because
of the presence of microcracks in the HAZ. 相似文献
12.
采用5052半硬铝带分别包覆Al_2O_3、SiC、B_4C、TiC陶瓷颗粒制备的粉芯丝材进行电弧喷涂试验,制备了含陶瓷颗粒的铝基复合涂层。利用光学显微镜、XRD分析了涂层的微观组织和相结构,测试了复合涂层的显微硬度、耐磨性及耐腐蚀性。研究结果表明,制备的铝基复合涂层中含有一定数量的未熔陶瓷颗粒,涂层较为致密,无明显缺陷。含陶瓷铝基涂层的物相主要由Al和所添加的陶瓷相构成,其中在含B_4C陶瓷涂层中还存在Al_3BC、Al_4C_3和AlB_2等新相。陶瓷颗粒的加入有利于提高铝基复合涂层的显微硬度,其中B_4C的加入使涂层中基体相显微硬度提高了1.5倍,这是由于B_4C陶瓷和Al反应生成Al_3BC、Al_4C_3和AlB_2硬质相。复合涂层的耐磨性均优于纯铝涂层,摩擦磨损的形式主要为粘着磨损。动电位极化腐蚀试验表明,含SiC和TiC陶瓷涂层具有较低的腐蚀电流,耐蚀性较好,含SiC陶瓷的复合涂层出现了明显的钝化现象。 相似文献
13.
A projection has been constructed for the liquidus surface on the plane of the concentration triangle for the Al2O3-ZrO2-Sm2O3 phase diagram. There are no ternary compounds, or appreciable regions of solid solutions based on the components and the
binary compounds. The liquidus surface is formed by nine fields of primary phase crystallization. There are five four-phase
nonvariant peritectic equilibria, as well as two four-phase nonvariant eutectic equilibria, and one three-phase nonvariant
eutectic equilibrium. As the ZrO2 and SmAlO3 phases interact with other phases by a eutectic mechanism, it is possible to combine the unique properties of the T and F
solid solutions based on ZrO2 with the properties of the other phases in the form of composites.
__________
Translated from Poroshkovaya Metallurgiya, Nos. 3–4(448), pp. 28–35, March–April, 2006. 相似文献
14.
Yu. G. Tkachenko V. I. Kovtun V. F. Britun D. Z. Yurchenko G. A. Bovkun 《Powder Metallurgy and Metal Ceramics》2005,44(7-8):407-414
The influence of deformation pre-treatment (milling in a planetary mill and shock-wave treatment) of B4C powders of different size composition on their structure as well as the structure and mechanical properties of samples that
have been hot-pressed from these powders is investigated. It is shown that treatment by shock waves produces a substantial
change in the structure of the powders, and this tends to increase the mechanical properties of the polycrystalline cakes.
__________
Translated from Poroshkovaya Metallurgiya, Nos. 7–8(444), pp. 118–127, July–August, 2005. 相似文献
15.
Kevin G. Ewsuk S. Jill Glass Ronald E. Loehman Antoni P. Tomsia William G. Fahrenholtz 《Metallurgical and Materials Transactions A》1996,27(8):2122-2129
Al2O3-Al(Si) and Al2O3-Al(Si)-Si composites have been formed byin situ reaction of molten Al with aluminosilicate ceramics. This reactive metal penetration (RMP) process is driven by a strongly
negative Gibbs energy for reaction. In the Al/mullite system, Al reduces mullite to produce α-Al2O3 and elemental Si. With excess Al (i.e., x > 0), a composite of α-Al2O3, Al(Si) alloy, and Si can be formed. Ceramic-metal composites containing up to 30 vol pct Al(Si) were prepared by reacting
molten Al with dense, aluminosilicate ceramic preforms or by reactively hot pressing Al and mullite powder mixtures. Both
reactive metal-forming techniques produce ceramic composite bodies consisting of a fine-grained alumina skeleton with an interpenetrating
Al(Si) metal phase. The rigid alumina ceramic skeletal structure dominates composite physical properties such as the Young’s
modulus, hardness, and the coefficient of thermal expansion, while the interpenetrating ductile Al(Si) metal phase contributes
to composite fracture toughness. Microstructural analysis of composite fracture surfaces shows evidence of ductile metal failure
of Al(Si) ligaments. Al2O3-Al(Si) and Al2O3-Al(Si)-Si composites produced byin situ reaction of aluminum with mullite have improved mechanical properties and increased stiffness relative to dense mullite,
and composite fracture toughness increases with increasing Al(Si) content.
This article is based on a presentation made in the “In Situ Reactions for Synthesis of Composites, Ceramics, and Intermetallics”
symposium, held February 12–16, 1995, at the TMS Annual Meeting in Las Vegas, Nevada, under the auspices of SMD and ASM-MSD
(the ASM/TMS Composites and TMS Powder Materials Committees). 相似文献
16.
Zhiping Luo Yinggang Song Shaoqing Zhang Dean J. Miller 《Metallurgical and Materials Transactions A》2012,43(1):281-293
In this work, B4C particulate-reinforced Al composite was fabricated by a pressureless infiltration technique, and its interfacial microstructure
was studied in detail by X-ray diffraction as well as by scanning and transmission electron microscopy. The B4C phase was unstable in Al melt during the infiltration process, forming AlB10-type AlB24C4 or Al2.1B51C8 as a major reactant phase. The Al matrix was large grains (over 10 μm), which had no definite orientation relationships (ORs) with the randomly orientated B4C or its reactant particles, except for possible nucleation sites with
{ 011}\textB4 \textC \{ 011\}_{{{\text{B}}_{4} {\text{C}}}} almost parallel to {111}Al at a deviation angle of 1.5 deg. Both B4C–Al and reactant–Al interfaces are semicoherent and free of other phases. A comparison was made with the SiC/Al composite
fabricated similarly by the pressureless infiltration. It was suggested that the lack of ORs between the Al matrix and reinforced
particles, except for possible nucleation sites, is the common feature of the composites prepared by the infiltration method. 相似文献
17.
M. Szafran G. Rokycki Z. Florianczyk E. Zygadlo-Monikowska 《Powder Metallurgy and Metal Ceramics》1999,38(5-6):228-231
Preliminary results are reported on the synthesis and use of new water-soluble polymer binders for making ceramic films from
Al
2O3 by casting. The binders produce cast materials having high contents of the solid phase and with rheological properties that
provide for good flow of the cast mass and for easy separation of the film from the substrate. The emulsions wet Al2O3 well, so one can make ceramic films with appropriate densities, elasticities, and mechanical strength in the raw state, and
these can be fired to make planeparallel specimens free from cracks and having high density, good mechanical strength, and
low roughness.
Warsaw Polytechnic. Translated from Poroskhovaya Metallurgiya, Nos. 5–6(407), pp. 15–20, May–June, 1999. 相似文献
18.
Yurii G. Tkachenko Viktor F. Britun Emmanuil V. Prilutskii Dzhemma Z. Yurchenko Galina A. Bovkun 《Powder Metallurgy and Metal Ceramics》2005,44(3-4):196-201
We have investigated how the composition, grain morphology, and method of preparing the starting mixture affect the processes that form the structure and phase composition of B4C - SiC composites during hot pressing. We found that, depending on the composition of the initial powder mixtures, which is responsible for different mechanisms of consolidation of ceramic materials during hot pressing, the grain size of the main B4C phase and its defect content as well as the nature of the SiC phase distribution within the material differ significantly. When B4C - SiC composites with a low SiC content are made from initial B4C - B4Si - B - C powder mixtures those composites have a high cracking resistance because of their fine grain structure.__________Translated from Poroshkovaya Metallurgiya, Nos. 3–4(442), pp. 112–119, March–April, 2005. 相似文献
19.
I. C. Barlow H. Jones W. M. Rainforth 《Metallurgical and Materials Transactions A》2001,32(12):2937-2945
The formation and coarsening of Al2O3 dispersoids have been investigated at 500 °C, 550 °C, and 600 °C in a mechanically alloyed (MA) extrusion of composition
Al-0.35wt pct Li-1wt pct Mg-0.25wt pct C-10vol pct TiO2 for times up to 1500 hours. In the as-extruded condition, the dispersed phases included Al3Ti, Al4C3, MgO, cubic TiO (C-TiO), monoclinic TiO (M-TiO), TiO2, and a small amount of Al2O3. However, numerous Al2O3 dispersoids (various polymorphs: η, γ, α, and δ) with “block-shaped” morphology were formed after heat treatment due to reduction of C-TiO, M-TiO, and TiO2. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) showed conclusively the transformation of these phases
to additional Al2O3 and Al3Ti. High resolution TEM showed that the α-Al2O3 dispersoids exhibited some lattice matching with the α-Al matrix. Coalescence of the block-shaped Al2O3 dispersoids occurred after heat treatment, and Al4C3 also became attached to them. The length and width of the block-shaped Al2O3 dispersoids increased by a factor of ∼1.55 between 340 and 1500 hours at 600 °C. 相似文献
20.
F. F. Egorov V. I. Novikova A. A. Mamonova 《Powder Metallurgy and Metal Ceramics》1998,37(7-8):415-420
The features of structure and phase composition of sintered heterophase materials based on TiN with Ni—Mo binder have been
studied. Molybdenum in the binder increases the material density in comparison with that of nickel binder. This seems to be
due to less release of nitrogen from TiN. After sintering, the binder consists of intermetallics of titanium with nickel and
molybdenum, as well as solid solution based on nickel and molybdenum. The effect of Al2O3 additives (20%) on the microstrucutre and phase composition of TiN—Ni—Mo was also studied. Sintering in argon ambient and
in vacuum results in increase of microhardness and lattice parameter of TiN caused by dissolution of nickel, molybdenum, and
oxygen in TiN.
Institute for Problems of Materials Science, Ukraine National Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya,
Nos. 7–8(402), pp. 82–89, July–August, 1998. 相似文献