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Showing papers on "Alloy published in 1985"


01 Jan 1985
TL;DR: In this article, the authors describe the behavior of grain boundaries in a two-dimensional model ordered alloy and the effects of elastic anisotropy on the anomalious yield behavior of cubic ordered alloys.
Abstract: This book contains over 50 selections. Some of the titles are: Order-disorder behavior of grain boundaries in a two-dimensional model ordered alloy; Dislocation reactions at grain boundaries in Ll/sub 2/ ordered alloys; Creep cavitation in a nickel aluminide; Effects of elastic anisotropy on the anomalious yield behavior of cubic ordered alloys; and Processing technology for nickel aluminides.

2,123 citations


Journal ArticleDOI
TL;DR: In this paper, a molybdenum containing austenitic steel was exposed in hydrochloric acid at various potentials in the active and passive ranges of the alloys.
Abstract: A molybdenum containing austenitic steel was exposed in hydrochloric acid at various potentials in the active and passive ranges of the alloys. The surface compositions were analyzed by the ESCA technique. The influence of pretreatment by ion bombardment and mechanical polishing on the passivation behavior was investigated. The passive film formed on the surface consists mainly of a mixed Fe‐Cr‐Mo oxide. The average content of Cr3+ in the oxide is about 70%. The inner layers of the oxide product consist mainly of Cr oxide. The Ni content in the oxide is low. The concentration and the chemical state of Mo is potential dependent. At low potentials in the passive range, the four‐valency state is predominant, while at high potentials Mo exists mainly in its six‐valency state. On the surface of the oxide, a layer of hydroxide is present. Chloride ions are incorporated into the passive film. The thickness of the passive film increases with the potential in the passive range from 10 to 15A. The composition of the metal phase changes during active dissolution. Thus, the alloying elements are enriched on the surface and thereby control the dissolution rate, control overpotentials, and provoke passivation of the alloy.

271 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that in the absence of sodium, molecular attachment by the TPRE mechanism is incidental but in the presence of sodium this is the dominant growth mechanism.

162 citations


Journal ArticleDOI
TL;DR: In this article, the structure of the shear bands in an α' martensite parent alloy appeared to be a tempered form of the original microstructure, modified by the effects of elevated temperature.

148 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a review of the structural material requirements, a summary of the materials data base for selected vanadium-base alloys with emphasis on the V-15Cr-5Ti alloy, and a comparison of projected performance characteristics compared to other candidate alloys.

141 citations


Journal ArticleDOI
TL;DR: In this paper, the form of the equilibrium phase diagram was determined to obtain information on the age hardening of chill cast alloys with up to 8.75wt% Sc alloy.
Abstract: Aluminium-rich alloys from the Al-Sc system were examined to determine the form of the equilibrium phase diagram and to obtain information on age hardening of chill cast alloys. Samples containing up to 8.75wt% Sc were examined using thermal analysis and optical microscopy. This work indicated a eutectic type of phase diagram with a eutectic temperature of about 665° C and a eutectic composition of about 0.6wt% Sc. The scandium-rich primary phase was found to be ScAl3 which is f c c with a lattice parameter of 0.4105nm. Chill cast samples of a 1 wt% Sc alloy were examined for their age hardening behaviour over the temperature range of 225 to 360° C. A maximum hardness of 77 VHN was obtained after ageing at 250° C for 3 days. This hardness was retained after ageing for a total of at least 12 days. The hardening precipitates were ScAl3 which were observed to form via a discontinuous precipitation mechanism. The ScAl3 precipitates were observed to have a parallel orientation relationship with the matrix.

132 citations


Journal ArticleDOI
TL;DR: In this article, the evolution of active current density with time has been measured on new surfaces of FeCr and FeCr-1.5 at. % Mo alloys.

132 citations


Journal ArticleDOI
TL;DR: In this article, the response of coevaporated amorphous films of a CuxW1−x (x=0.45-0.72) and a cuxTa1−X (x = 0.10−0.55) alloys to thermal annealing and ion irradiation is investigated.
Abstract: Although both the Cu/W and Cu/Ta alloy systems are known to be immiscible, the response of coevaporated amorphous films of a‐CuxW1−x (x=0.45–0.72) and a‐CuxTa1−x (x=0.10–0.55) alloys to thermal annealing and ion irradiation is very different. Alloys of a‐CuxTa1−x crystallize between 600 and 800 °C, with the crystallization temperature increasing with Ta concentration, while a‐CuxW1−x alloys crystallize below 200 °C. Likewise in Xe‐ and Ne‐ion irradiation studies, a‐Cu/Ta can still be observed after ∼13 displacements per atom (DPA), whereas a‐Cu/W alloys completely transform to solid solutions after ∼0.08 DPA. The results of this study, in combination with previous investigations of amorphous alloys of immiscible systems, show that the crystallization temperature Tc is not predicted equally well for systems with a positive or negative heat of formation. It appears that the kinetic model of crystallization only applies if the transformation proceeds through long‐range diffusion. Amorphous alloys which have ...

132 citations


Patent
09 Dec 1985
TL;DR: A composite compact component made of a composite compact consisting of a diamond or BN powder bonded to a hard sintered alloy base during a sintering operation is described in this article.
Abstract: A composite compact component made of a composite compact consisting of a diamond or BN powder bonded to a hard sintered alloy base during a sintering operation, and a substrate composed of steel or a hard sintered alloy bonded to the base of the composite compact through a high strength filler metal or alloy having a melting point of at least the liquidus point of the hard sintered alloy base. A process of making set composite compact component is also disclosed as well as a drill bit containing said composite compact component and variations thereof.

122 citations


Journal ArticleDOI
TL;DR: In this article, the precipitation reactions responsible for age hardening in a highconductivity Cu-Cr-Zr-Mg alloy have been investigated by analytical transmission electron microscopy and compared briefly with the processes that occur in simpler Cu−Cr and CU-Cr -Mg alloys.
Abstract: The precipitation reactions responsible for age hardening in a high-conductivity Cu–Cr–Zr–Mg alloy have been investigated by analytical transmission electron microscopy and compared briefly with the processes that occur in simpler Cu–Cr and Cu–Cr–Mg alloys. Aging at low temperatures (400°C) results in the formation of Guinier–Preston zones. Peak hardness, obtained by aging for 24 h at 450°C, is found to be a result of the fine scale precipitation of an ordered compound, possibly of the Heusler type, with the suggested composition CrCu2(Zr, Mg). Overaging results in the formation of coarse precipitates of Cr and CU4Zr. The intergranular precipitate which forms in the Cu–Cr–Zr–Mg alloy is Cu4Zr. This phase precipitates both as discrete particles on the grain boundaries and as thin ( ~ 5 nm) continuous intergranular films.MST/89

109 citations


Journal ArticleDOI
TL;DR: In this paper, the dissociation plateau pressure at 20°C was obtained in a range from 0.01 MPa (for Ti 0.9 Zr 0.4 V 0.2 Cr 0.1 Mn 1.4 -H).

Journal ArticleDOI
TL;DR: In this article, the effect of magnetic field on the martensitic transformation in FeNi alloys was examined by carrying out magnetization measurements and optical microscopy for Fe-29.9 and −32.5 at.

Journal ArticleDOI
TL;DR: The microstructure of ZrO2-Y2O3 alloys prepared by arc-melting was examined mainly by electron microscopy as mentioned in this paper, and it was found that the micro-structure changed markedly with yttria content between 0 and 8·7 mol.
Abstract: The microstructure of ZrO2-Y2O3 alloys prepared by arc-melting was examined mainly by electron microscopy. It was found that the microstructure changed markedly with yttria content between 0 and 8·7 mol%. Pure zirconia was a single monoclinic phase, while ZrO2-8·7 mol% Y2O3 alloy was single cubic phase as expected from ZrO2-Y2O3 phase diagram. Tetragonal phase was found in alloys with 1 to 6 mol% Y2O3 together with monoclinic or cubic phase. The tetragonal phase found in present alloys normally had a lenticular shape with a length 1 to 5μm and a width 0.1 to 0.3μm, which is much larger than that formed by annealing. The phase with a herring-bone appearance was found in alloys with Y2O3 between 2 and 3 mol%, which was recognized to be a metastable rhombohedral phase. The structure of the present alloys is likely to be formed by martensitic or bainitic transformation during fairly rapid cooling from the melt temperature. The change in hardness and toughness with yttria content of the alloys is discussed on the basis of microstructural observations.

Journal ArticleDOI
TL;DR: In this paper, the effect on the nitriding behavior of an FeCrC alloy, as a model system for En40B (a classical gas-nitriding steel), was investigated by comparing the response of a hardened structure, a quenched and tempered structure and an annealed structure.
Abstract: The nitriding behaviour of an FeCrC (3.16 wt% Cr, 0.20 wt% C) alloy, as a model system for En40B (a classical gas-nitriding steel), was investigated. By comparing the response of a hardened structure, a quenched and tempered structure and an annealed structure, the effect on nitriding of different initial chromium and carbon disbributions over the phases present could be studied. The structure after nitriding was described employing metallographic methods (optical and scanning electron microscopy; hardness measurements), electron microprobe analysis (concentrationdepth profiles) and X-ray diffractometry (residual macrostress determination; phase identification). Further the weight and thickness increases of the specimens during nitriding were determined. During initial stages of nitriding, excess-nitrogen uptake and the development of grain-boundary carbides and a compressive residual surface macrostress took place. At later stages discontinuous precipitation, void formation, decarburization and relaxation of the compressive residual macrostress occurred. The observations lead to a model description for the nitriding of an FeCrC alloy.

Journal ArticleDOI
M.Y. Song1, E. I. Ivanov1, Bernard Darriet1, M. Pezat1, Paul Hagenmuller1 
TL;DR: In this article, the hydrogen properties of a mechanically alloyed 2Mg + Ni mixture have been investigated and compared with those of the Mg2Ni alloy prepared by melting and sintering.

Journal ArticleDOI
TL;DR: In this article, the formation of the passive films (or corrosion) occurred in deoxygenated 0.1 M NaCl solution (pH=5.6), from which the samples were transferred directly to the XPS chamber under controlled atmosphere (Ar).
Abstract: Five commercial steels ranging from the martensitic stainless steel containing 12% chromium to the superferrite containing 29% chromium, 4% molybdenum, and 2% nickel have been studied by XPS. In addition, a pure iron-chromium alloy containing 7% chromium has been investigated. Armco iron and pure chromium (99.99%) were included as references. The formation of the passive films (or corrosion) occurred in deoxygenated 0.1 M NaCl solution (pH=5.6), from which the samples were transferred directly to the XPS chamber under controlled atmosphere (Ar). Concentration profiles (at.-%) of the alloy constituents in their oxidized and metallic states have been determined separately from the measured XPS depth profiles. Forc≳= 12% chromium the passive films have the following structure: there is a depletion of Cr in the inner region, followed by an enrichment (concentration maximum) in the central region of the films. The height of this maximum increases, and its position shifts towards the surface with increasing chromium content in the alloy. The outermost monolayers are rich in water and hydroxyl groups. Various significant properties of the films change drastically at the critical chromium concentration of about 12%. This behaviour is rather independent of the other components (Mo, Ni, Cu) present in the alloys and is discussed in terms of a phase transition in the films which is controlled by the chromium concentration.

Journal ArticleDOI
01 Nov 1985-JOM
TL;DR: Zinc-aluminum (ZA) alloys are a relatively new family of zinc foundry alloys having superior melting and casting characteristics and attractive mechanical properties as mentioned in this paper, which can be sand cast, permanent molded and pressure die cast.
Abstract: Zinc-aluminum (ZA) alloys are a relatively new family of zinc foundry alloys having superior melting and casting characteristics and attractive mechanical properties. The ZA-8 and ZA-12 alloys are moderate to high strength materials while ZA-27 is a high-strength alloy. All can be sand cast, permanent molded and pressure die cast.

Journal ArticleDOI
TL;DR: In this paper, fine particles of hydrogen storage alloys such as LaNi5 and MmNi4 were encapsulated in a thin layer of copper 1-2 μm thick by means of a special chemical plating method.
Abstract: Fine particles of hydrogen storage alloys such as LaNi5 and MmNi4.5-Mn0.5 (Mm  misch metal) were encapsulated in a thin layer of copper 1–2 μm thick by means of a special chemical plating method. This treatment prevented further disintegration of the metal and improved the thermal conductivity. The alloy-copper microcapsules, which had dimensions of less than 30 μm, were able to absorb hydrogen easily without special activation and exhibited no decrease in hydrogen storage capacity. Pellets obtained by compressing the microencapsulated powder under a pressure of 5–10 tf cm−2 did not show any visible cracks after 1000 hydrogen sorption cycles.

Journal ArticleDOI
M. Landkof1, A.V. Levy1, D.H. Boone1, R. Gray1, E. Yaniv1 
TL;DR: In this paper, the influence of surface application of active elements on the composition, morphology, adherence, and growth rate of oxide scales formed during high temperature exposure has been investigated, and the active elements were applied as aqueous solutions of nitrate salts that were subsequently transformed into oxide.
Abstract: The influence of the surface application of active elements on the composition, morphology, adherence, and growth rate of oxide scales formed during high temperature exposure has been investigated. The active elements were applied as aqueous solutions of nitrate salts that were subsequently transformed into oxide. The active elements used were: Y, Ce, La, Hf, Ca, and Zr. The chromia-forming substrates used were AISI 304 and 310 stainless steels and IN 738, a nickel base alloy. To determine the effect of the minor alloying elements in stainless steels on the surface doping effect, Y was applied to three alloy modifications of AISI 304. The effect of the presence or absence of Mn and Si in the alloy on high temperature corrosion behavior was determined. Several different application techniques were used to determine which technique was most beneficial to the behavior of the oxide barrier scale. The application of Y, Ce, and La was found to enhance the oxidation resistance of the commercial stainles...

Journal ArticleDOI
TL;DR: In this paper, the authors used simultaneous vapor deposition of elements on unheated substrates to produce alloy films covering the complete composition range of those three binary alloy systems and characterized the films with the help of x-ray diffraction, transmission electron microscopy, and electron diffraction.
Abstract: The equilibrium phase diagrams of Cu–Cr, Cu–Mo, and Cu–W show no measurable solid solubility except for a small solubility of Cr in solid Cu at higher temperatures. Even in the liquid state, the mutual solubilities in these systems are very limited. Simultaneous vapor deposition of elements on unheated substrates was used to produce alloy films covering the complete composition range of those three binary alloy systems. The films were characterized with the help of x‐ray diffraction, transmission electron microscopy, and electron diffraction. In fcc Cu films, at least 10 at.% Cr, Mo, or W may be dissolved, whereas the bcc Cr, Mo, or W alloy films may accommodate at least 40 at.% Cu; the fcc and bcc solid solutions are separated by narrow two‐phase fields. We further measured the composition dependence of the internal stress and of the electrical resistivity. Discontinuities in the measured curves generally coincide with the presence of phase boundaries in the (metastable) alloy films.

Journal ArticleDOI
TL;DR: A semi-mechanistic model for predicting the flow behavior of a typical commercial dual-phase steel containing 20 vol pct of "as quenched" martensite and varying amounts of retained austenite has been developed in this article.
Abstract: A semi-mechanistic model for predicting the flow behavior of a typical commercial dual-phase steel containing 20 vol pct of ‘as quenched’ martensite and varying amounts of retained austenite has been developed in this paper. Assuming that up to 20 vol pct of austenite with different degrees of mechanical stability can be retained as a result of certain thermomechanical treatments in a steel of appropriate low carbon low alloy chemistry, expressions for composite flow stress and strain have been derived. The model takes into account the work hardening of the individual microconstituents(viz., ferrite-@#@ α, retained austenite- γr, and martensite -α′) and the extra hardening of ferrite caused by accommodation dislocations surrounding the ‘as quenched’ as well as the strain-induced(γr→ α′) martensite. Load transfer between the phases has been accounted for using an intermediate law of mixtures which also considers the relative hardness of the soft and the hard phases. From the derived expressions, the flow behavior of dual phase steels can be predicted if the properties of the individual microconstituents are known. Versatility of the model for application to other commercial steels containing a metastable phase is discussed.

Journal ArticleDOI
TL;DR: In this paper, the laser surface alloying of commercial purity (CP) Ti and Ti-6Al-4V alloy with carbon and of CP Ti andTi-15 Mo alloy with nitrogen was reported.
Abstract: Observations are reported on the laser surface alloying of commercial purity (CP) Ti and Ti–6Al–4V alloy with carbon and of CP Ti and Ti–15 Mo alloy with nitrogen. Repeated laser melting of substrates precoated with Dag graphite was used for carbon alloying, while alloying with nitrogen was done by laser melting in a nitrogen flow. Structural studies included X-ray diffraction and electron microscopy. Both alloying procedures produce hardened surface layers up to ∼650 HV using carbon and >∼ 1000 HV using nitrogen. This hardening resulted from the formation of TiC and TiN respectively, including primary dendritic carbide and nitride.

Patent
01 Mar 1985
TL;DR: Amorphous metal alloy powders may be synthesized by solid state reactions as discussed by the authors, where precursor components that include the elements of the amorphous alloy are chemically reduced to yield an intimate mixture.
Abstract: Amorphous metal alloy powders may be synthesized by solid state reactions. Precursor components that include the elements of the amorphous alloy are chemically reduced to yield an intimate mixture. The resultant intimate mixture, as obtained or after heat-treating, exhibits amorphous characteristics. These powders are suitable for forming solid amorphous shapes.

Patent
22 Nov 1985
TL;DR: In this paper, a novel iron-based alloy is disclosed which is characterized by high resistance to wear and corrosion, and is available in the form of a powder for thermal spraying, and coatings produced thereby may have an amorphous structure.
Abstract: A novel iron based alloy is disclosed which is characterized by high resistance to wear and corrosion. The alloy consists essentially of 0 to 40% chromium, 1 to 40% molybdenum, 1 to 15% copper, 0.2 to 5% boron, and 0.01 to 2% carbon; the balance being incidental impurities and at least 30% iron, with the molydenum being at least 10% if the boron is greater than 2%. The alloy is preferably in the form of a powder for thermal spraying, and coatings produced thereby may have an amorphous structure.

Patent
22 Jan 1985
TL;DR: The article is formed by beta-treating the alloy, initially deforming the same at a temperature below 650°C. and further deforming it through cold working stages also below 6°C as mentioned in this paper.
Abstract: Articles, such as tubing, which have excellent corrosion resistance to steam at elevated temperatures and to hydriding, are produced from zirconium alloys containing 0.5 to 2.0 percent niobium, up to 1.5 percent tin, and up to 0.25 percent of a third alloying element such as iron, chromium, molybdenum, vanadium, copper, nickel and tungsten. The articles are formed by beta-treating the alloy, initially deforming the same at a temperature below 650° C. and further deforming the same through cold working stages also below 650° C., annealing the material between the cold working stages at a temperature between 500°-650° C., and final annealing the same at a temperature below 650° C. to provide articles having a microstructure of fine precipitates of less than about 800 Å, homogeneously dispersed throughout the zirconium.

01 Jan 1985
TL;DR: The Materials Research Society Symposium on High-Temperature Ordered Intermetallic Alloys as mentioned in this paper provided a forum to discuss the alloy chemistry, physical metallurgy, and mechanical behavior of ordered intermetallic alloys which have potential to be used as new structural materials.
Abstract: : For several decades the special properties of ordered intermetallic alloys have intrigued alloy designers. In particular, the aluminides offered the potential for high temperature structural applications due to good strength combined with oxidation resistance. Attainment of this potential has been hampered by the brittle behavior and low fracture toughness of these materials. However, in recent years significant improvement in the ductility and toughness of, at first, titanium aluminides, then iron and nickel aluminides, has been achieved by metallurgical techniques such as processing control, grain refinement, and microalloying. These successes have stimulated new interest in ordered intermetallics - in particular the aluminides. The Materials Research Society symposium on High-Temperature Ordered Intermetallic Alloys provided a forum to discuss the alloy chemistry, physical metallurgy, and mechanical behavior of ordered intermetallic alloys which have potential to be used as new structural materials. The symposium contained presentations in the areas of theory of alloy ordering, microstructural features and phase transformation, mechanical behavior, alloy design, and physical properties.

Journal ArticleDOI
TL;DR: AES, ELS, LEED, AES and XPS investigations of the surface segregation of tin dissolved in a Fe-4wt%Sn alloy were performed in ultra-high vacuum at elevated temperatures as discussed by the authors.

Patent
05 Dec 1985
TL;DR: An electrode wire for wire electric discharge machining a workpiece at high speed and high accuracy and a process for preparing the same are provided in this article, where the electrode wire comprises a core wire made of a copper clad steel wire, 10 to 70% of the sectional area of the copper-clad steel wire being occupied by copper, and a copper-zinc alloy layer covering the core wire.
Abstract: An electrode wire for wire electric discharge machining a workpiece at high speed and high accuracy and a process for preparing the same are provided. The electrode wire comprises a core wire made of a copper clad steel wire, 10 to 70% of the sectional area of the copper clad steel wire being occupied by copper, and a copper-zinc alloy layer covering the core wire. The copper-zinc alloy layer is prepared by coating the core wire with zinc by electroplating or hot galvanizing, followed by heating to disperse copper in the zinc layer to convert the same into a copper-zinc alloy layer wherein the concentration of zinc is increased gradually along the radially outward direction. The preferable thickness of the copper-zinc alloy layer ranges from 0.1 to 15 microns and the average concentration of zinc in the copper-zinc alloy layer is preferably less than 50% by weight but not less than 10% by weight.

Journal ArticleDOI
TL;DR: In this article, the effect of thermal treatment and orientation on the fracture toughness of SiC whisker reinforced-6061 aluminium metal matrix composite material from an extruded tube has been determined.
Abstract: Mechanical, instrumented Charpy V-notch (CVN) energy and plane strain fracture toughness properties of SiC whisker reinforced-6061 aluminium metal matrix composite material from an extruded tube have been determined. The effect of thermal treatment and orientation have been studied. The mechanical strength properties are higher than wrought Al 6061 in the T6 condition. CVN energy values, however, were reduced by an order of magnitude.Klc fracture toughness of the as-received, T6 and degassed + T6 thermal treatments were 50% of the wrought Al 6061 alloy. The effect of orientation showed that the orientation with the least amount of SiC whisker in the crack plane (i.e. greatest mean free path between reinforcements) yields the highest toughness value.

Journal ArticleDOI
TL;DR: The galvanic current densities between gold, amalgam and cobalt-chromium, three different classes of dental alloys, were determined in vitro in artificial saliva kept at 35 degrees C.
Abstract: The galvanic current densities between gold, amalgam and cobalt-chromium, three different classes of dental alloys, were determined in vitro in artificial saliva kept at 35 degrees C. The maximum current density of 200 microA/dm2 was obtained between the conventional amalgam and a type III gold alloy. Galvanic currents of lesser magnitude could also be measured between amalgams high in copper and the other alloys. No measurable current densities were obtained between gold alloys and between gold and cobalt-chromium alloy with the exception of a casting and a solder gold alloy commonly used in combination.