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Showing papers on "Aluminium alloy published in 1987"


Journal ArticleDOI
TL;DR: In this paper, the authors reviewed the data and information available through March 1985 on the various thermodynamic properties of five binary aluminum alloy systems: AlFe, AlMn, AlNi, AlSi, and AlTi.
Abstract: This work reviews the data and information available through March 1985 on the various thermodynamic properties of five binary aluminum alloy systems: Al–Fe, Al–Mn, Al–Ni, Al–Si, and Al–Ti The thermodynamic properties covered in this work are heat capacity, Gibbs energy, enthalpy, and entropy of formation Existing data have been evaluated and analyzed The values for heat capacity and room‐temperature enthalpy of formation for a large number of alloys have been generated For each of the binary alloy systems, the recommended values for integral Gibbs energy, enthalpy, and entropy of formation as well as the partial quantities, activity, and activity coefficients for each component covering the entire composition range have been reported These values are reported for both solid and liquid alloys

164 citations


Journal ArticleDOI
TL;DR: In this paper, it is suggested that the S'-phase lattice-parameter measurements are only a slightly strained version of the Al2CuMg-S phase and need not be distinguished from it.
Abstract: The aluminium alloy considered in this paper has a Cu/Mg ratio of 1·94 with 1·53 wt% Cu and 0·79 wt% Mg. It has been observed that on ageing at 190°C, S' precipitates form and grow as rods parallel to M cubic matrix directions with a slight tendency to cluster in groups on {110}M f.c.c. matrix planes. These groups of precipitates did not however coalesce to form laths on the {110}M or {210}M planes as has been reported in alloys with similar Cu/Mg ratios. The accepted orientation relationship has been confirmed and used to simulate a detailed and complete S'-phase diffraction pattern and morphological structure which agrees with electron microscope observations. It is suggested that lath formation is dependent upon the (Cu + Mg) concentration, which is low enough in this alloy to prevent it. Based on S'-phase lattice-parameter measurements, it is suggested that the S' precipitates are only a slightly strained version of the Al2CuMg-S phase and need not be distinguished from it.

136 citations


Journal ArticleDOI
TL;DR: The effect of the alloy matrix on room-temperature strengthening in δ-alumina-reinforced aluminium alloys has been investigated in this paper, where it is shown that a simple Rule of Mixtures (ROM) strength analysis, modified to account for the discontinuous and random orientation of the reinforcement, can adequately explain these responses.
Abstract: The effect of the alloy matrix on room-temperature strengthening in δ-alumina-reinforced aluminium alloys has been investigated. Alloy matrices fell into two families exhibiting significantly different fibre-strengthening response. The first gave rise to little or no improvement in the room-temperature strength, while the second gave significant improvements by up to 300%. It is shown that a simple Rule of Mixtures (ROM) strength analysis, modified to account for the discontinuous and random orientation of the reinforcement, can adequately explain these responses. Little or no reinforcement occurs when the matrix properties result in a high value for the critical volume fraction VCRIT which must be exceeded to produce any increase in strength. However, by careful selection of the matrix alloyV CRIT can be reduced, thus giving significant reinforcement of the room-temperature strength. This analysis shows that for optimum room-temperature reinforcement the matrix alloys should exhibit a low rate of work-hardening. In certain alloys reinforcement levels were in excess of those predicted by the ROM analysis. It is proposed that this occurs in relatively low-strength matrices as a result of dispersion strengthening of the matrix due to the presence of the fibre array.

131 citations


Journal ArticleDOI
TL;DR: In this paper, the conditions in a simulated crevice have been studied for type 304 stainless steel and for 7475 T651 Al-ZnMg alloy in 0.6 M NaCl bulk solutions.

82 citations


Journal ArticleDOI
TL;DR: In this paper, the electrochemical response of Al alloys containing various concentrations of Mo in solid solution was studied using potentiodynamic polarization, and the evolution of the chemical composition of the passive film during exposure to deaerated O.1N KCl was analyzed using x-ray photoelectron spectroscopy.
Abstract: The electrochemical response of Al alloys containing various concentrations of Mo in solid solution was studied using potentiodynamic polarization. The evolution of the chemical composition of the passive film during exposure to deaerated O.1N KCl was analyzed using x-ray photoelectron spectroscopy. Exposure of Al-Mo alloys to the chloride solution results in an increase in the corrosion potential and a decrease in the cathodic Tafel slope. The breakdown potential is also found to increase with higher concentrations of Mo in the alloy. These results correlate with an increase in the amount of Mo in the oxide film during polarization, even though the concentration of Mo in the passive film is well below that in the alloy. This work suggests that the oxidized Mo in the passive film inhibits the nucleation of pits in the alloy by improving the integrity of the passive film.

57 citations


Journal ArticleDOI
TL;DR: In this paper, the authors examined the mechanisms causing crack growth retardation after an overload for BS4360 50B steel and 2014A-T4 aluminium alloy and found that plasticity-induced crack closure is the main cause of retardation when the pre-overload growth rate is in the mid-regime of the growth rate versus stress intensity range plot.
Abstract: The mechanisms causing crack growth retardation after an overload were examined for BS4360 50B steel. It was found that plasticity-induced crack closure is the main cause of retardation when the pre-overload growth rate is in the mid-regime of the growth rate versus stress intensity range plot. When the pre-overload growth rate is near threshold it is argued that retardation at the surface of the specimen is primarily due to strain hardening and to the build-up of a favourable residual stress distribution in the material ahead of the crack tip. Supporting evidence for this argument is provided by a preliminary test on 2014A-T4 aluminium alloy. Plasticity-induced crack closure may be a further cause of retardation in the bulk, plane strain regions of the specimens made from BS4360 50B steel and 2014A-T4 aluminium alloy, when the pre-overload growth rate is near threshold.

55 citations


Journal ArticleDOI
TL;DR: In this paper, the relative amounts of Ω and θ′ precipitate have been measured as a function of aging time, analysis of the data showing that growth is diffusion controlled with an activation energy of 136± 15 kJ mol−1.
Abstract: Adding small amounts (<1wt-%) of both magnesium and silver to an aluminium alloy containing about 4 wt-% Cu causes precipitates with a hexagonal structure (Ω-phase) to form on {111} planes of the aluminium lattice. Precipitation of θ′ on {100} planes may also occur, the relative proportions of the two types of precipitate being dependent on the levels of magnesium and silver, e.g. ~0·7 wt-% of each element almost entirely suppresses θ′ formation. Even when θ′ does form in parallel with Ω-phase, on prolonged aging it tends to dissolve in favour of Ω growth. Using an X-ray technique to establish foil thickness, the relative amounts of Ω and θ′ precipitate have been measured as a function of aging time, analysis of the data showing that growth is diffusion controlled with an activation energy of 136± 15 kJ mol−1.MST/648

53 citations


Journal ArticleDOI
TL;DR: In this article, cyclic mechanical tests were carried out on specimens of an Al-Mg-Si alloy, 6351, in the solution treated condition and the behaviour compared to that of a non-precipitation hardened aluminium alloy, 5182.

40 citations


Journal ArticleDOI
TL;DR: In this article, the authors studied the interaction between Al-Si, Al-Ge, and Zn-Al eutectic alloys with SiC whisker-reinforced aluminium metal matrix composites.
Abstract: Interactions between Al-Si, Al-Ge, and Zn-Al eutectic alloys with SiC whisker-reinforced aluminium metal matrix composites were studied as a function of temperature above the eutectic melting temperature. Penetration extended several millimetres into the composite for the Al-Si and Al-Ge alloys but was restricted to a thin surface layer (50 μm) for the Zn-Al alloy. The extent of the penetration zone for the aluminium alloys containing silicon and germanium was also affected by the thermal-mechanical treatment of the composite: limited penetration was observed for hot-pressed material whereas extensive penetration was observed for mechanically worked material. Mechanisms for the observed phenomena are discussed in terms of the wettability of the SiC whiskers by the eutectic alloys, the formation of channels during mechanical working as well as the fine grain size of the composite.

38 citations


Journal ArticleDOI
TL;DR: In this article, the melt-quenching technique has been used to obtain aluminium-based superconducting alloys including finely dispersed lead or Pb-Bi particles, which has been found to result in the preparation of materials consisting of fcc Pb or h c p e(Pb-bi) particles dispersed finely and densely in the aluminum-based matrix in each composition range below about 2 at % Pb for Al-Pb alloys and 5 at % pb or (Pb + Bi) for (Al0.9 Si 0.4
Abstract: In order to obtain aluminium-based superconducting alloys including finely dispersed lead or Pb-Bi particles, the application of the melt-quenching technique has been tried for Al-Pb, Al-Si-Pb and Al-Si-Pb-Bi alloys containing immiscible elements such as lead and bismuth. It has been found to result in the preparation of superconducting materials consisting of fcc Pb or h c p e(Pb-Bi) particles dispersed finely and densely in the aluminium-based matrix in each composition range below about 2 at % Pb for Al-Pb alloys and 5 at % Pb or (Pb + Bi) for (Al0.9 Si0.1)100−x Pbx and (Al0.9Si0.1)100−x (Pb0.6Bi0.4)x alloys. The particle size and interparticle distance were ∼ 40 nm and 40 to 100 nm, respectively, within the grains, and ∼ 100 nm and below ∼ 30 nm, respectively, at the grain boundaries for the lead phase in Al98 Pb2 alloy. Particle size was ∼ 15 to 60 nm and interpartide distance 30 to 60 nm for the Pb- Bi phase in (Al0.9 Si0.1)95(Pb0.6 Bi0.4)5 Transition temperature,Tc was 4.16 K for Al98Pb2, 3.94K for (Al0.9Si0.1)95 Pb5 and 7.75 K for (Al0.9Si0.1)95(Pb0.6Bi0.4)5. The upper critical magnetic field,Hc2, and critical current density,Jc, for (Al0.9Si0.1)95(Pb0.6Bi0.4)5 were 0.22 T at 4.2 K and 1.67 × 107 Am−2atzeroappliedheld and 4.2 K. The appearance of the superconductivity for the aluminium -based alloys was interpreted as due to the formation of superconducting percolation path along the tangled dislocations, sub-boundaries and/or grain boundaries where Pb and Pb-Bi phases precipitated preferentially.

38 citations


Journal ArticleDOI
TL;DR: In this paper, single lap joints of aluminium alloy bonded with three phenol-based and one modified epoxide adhesive have been aged at 100% relative humidity (r.h) or at 50% r.h. for up to 10,000 hours at 50°C.
Abstract: Single lap joints of aluminium alloy bonded with three phenol-based and one modified epoxide adhesive have been aged at 100% relative humidity (r.h) or at 50% r.h. for up to 10,000 hours at 50°C. Whilst joints are not significantly weakened on exposure at 50% r.h., at 100% r.h. strength falls over about 2000 h and then tends to remain steady. This fall in strength is controlled by the rate at which water enters the adhesive layer. Some joints were exposed firstly at 100% r.h. for 5000 h., and then at 50% r.h. for a further 5000 h whereupon some recovery of strength took place. The effect of moisture on joint strengths can be interpreted in terms of water, by virtue of its high permittivity, weakening ion-pairs at the interface. X-ray photoelectron spectroscopy has been used to examine fracture surfaces at all stages, showing that visual inspection can lead to false conclusions about the mode of failure.

Patent
27 May 1987
TL;DR: In this article, the photo resist stripping process following the etching process is carried out by a downstream stripping process using a conventional etching gas, such as CF₄ + O₂, at room temperature, and, before the resist-stripped substrate is exposed to the atmosphere, the substrate is heated in a vacuum at higher than 100°C, thus the residual chlorine component is removed.
Abstract: An interconnection pattern made of aluminum alloy, such as Al-Cu, on a semiconductor IC is dry etched in an etching gas. When an etching gas containing chlorine is used, residual chlorine on the substrate is difficult to remove, and causes corrosion of the patterned aluminum alloy layer. According to the present invention, the photo resist stripping process following the etching process is carried out by a downstream stripping process using a conventional etching gas, such as CF₄ + O₂, at room temperature, and, before the resist-stripped substrate is exposed to the atmosphere, the substrate is heated in a vacuum at higher than 100°C, thus the residual chlorine component is removed. The heating process can be carried out concurrently during the resist stripping process. By this means corrosion of the aluminum alloy interconnection is prevented.


Journal ArticleDOI
TL;DR: The radiographic density of a typical age-hardening aluminium alloy containing 4 per cent copper was found to exceed significantly that of aluminium of 99·5 per cent purity, and the radiopacity of materials when expressed in terms of ‘equivalent thickness of metal’ is greater relative to pure aluminium than with this type of aluminium alloy.

Journal ArticleDOI
TL;DR: Etude de la vitesse de refroidissement et de rotation sur la structure des alliages. Caracterisation par microscopie optique as mentioned in this paper, et al.
Abstract: Etude de la vitesse de refroidissement et de rotation sur la structure des alliages. Caracterisation par microscopie optique

Journal ArticleDOI
TL;DR: In this article, a fabrication process for SiC whisker reinforced aluminium composites is developed, where the first step involves preforming the SiC Whisker and squeeze-infiltrating the molten metal into the preform.
Abstract: A fabrication process for SiC whisker reinforced aluminium composites is being developed. Theftrst step involves preforming the SiC whisker and squeeze-infiltrating the molten metal into the preform. Secondary fabrication can involve a conventional hot metal working practice such as extrusion. Microscopic observations indicate that the distribution of whiskers is very homogeneous. In an aluminium alloy (AA 6061) matrix composite containing 17 vol.-% SiC whiskers, the Young's modulus is > 100 GPa and the tensile strength increases by ~ 50–70% above that of the matrix to 460 and 529 MN m−2 in the cast and extruded products, respectively. The strength at elevated temperature and the wear resistance are also improved. These enhanced properties make the composite potentially suitable for a number of automotive applications.MST/574

Journal ArticleDOI
TL;DR: In this paper, cooling rate during solidification of the aluminium-silicon alloy A-356 was found to have a pronounced effect not only on the structure and mechanical properties, but also on the modification process using Al-5 mass% Sr master alloy.
Abstract: The cooling rate during solidification of the aluminium-silicon alloy A-356 was found to have a pronounced effect not only on the structure and mechanical properties, but also on the modification process using Al-5 mass% Sr master alloy. Cooling rates in the range of 0.2 to 5 K sec−1 were conducted using different types of moulds. Decreasing the cooling rate increases the degree of modification obtained, and a cooling rate of 0.2 K sec−1 showed the optimum modification in the present study. The mechanical properties were significantly improved by modification. Ductility of the modified alloy was eight times greater than that for the non-modified one. Moreover, the mechanical properties of the modified alloys, in the present study, were higher than those modified with sodium, and additionally the ductility of the present modified alloy was higher than that for alloys modified with strontium. A tendency towards ductile rupture was observed. The transgranular type of fracture was optically detected, and a dimple-pattern was observed on the fracture surface by scanning electron microscopy.

Patent
12 Nov 1987
TL;DR: In this article, the main constituent phase is an intermetallic compound, TiAl and the balance being Ti and inevitable impurities, which is suitable as materials for mechanical parts of rotating or reciprocating systems where high heat-resistance and high specific strength are required.
Abstract: Disclosed are Ti-Al alloys having increased ductility and Ti-Al alloys having increased ductility and lowered melting points, in both of which the main constituent phase is an intermetallic compound, TiAl. The Ti-Al alloys having increased ductility essentially consisting of Al: 28-38%, and B: 0.005-0.3%, the balance being Ti and inevitable impurities. Since the alloys of this type have good proces­sability, they are suitable as materials for mechanical parts of rotating or reciprocating systems, where high heat-resistance and high specific strength are required. The Ti-Al alloys having increased ductility as well as lowered melting points essentially consisting of Al: 28-38%, one or two of Ni: 0.05-3.0% and Si: 0.05-3.0%, and the balance being Ti and inevitable impurities. Optionally, this alloy further contains B: 0.005-0.3%. The alloy of this type is, in addition to the above use, suitable for producing machine parts made by precision casting technology.

Journal ArticleDOI
TL;DR: In this article, the behavior of a few Al-Mg alloys (up to 7.1 wt% Mg) has been studied on heating in air at 500°C for 8 h or more.
Abstract: The behaviour of a few Al-Mg alloys (up to 7.1 wt% Mg) has been studied on heating in air at 500°C for 8 h or more. The precipitation of a spinel phase, MgAl2O4, is found to take place on the surface and along the transverse section (depth) of the specimen. The alloys seem to be resistant to internal oxidation below 4.5% Mg and thereafter prone to it. Beryllium modification does not suppress the progress of internal oxidation taking place in the Al-Mg alloys. The results have been interpreted on the basis of anodized photomicrographs and X-ray diffraction data.

Patent
17 Jun 1987
TL;DR: In this paper, a method of making aluminium alloy is described, whereby the alloy contains Zr and from 0 to 1% of one or more of the elements Mg, Si, Ag, Ni and Cu, the balance being mainly Al.
Abstract: Aluminium alloy and a method of making it, whereby the alloy contains Zr and from 0 to 1% of one or more of the elements Mg, Si, Ag, Ni and Cu, the balance being mainly Al, the alloy being made on the basis of a melt which contains 0.5 to 2% by weight of Zr and which has been cast into particles by being cooled with such a high velocity that the Zr mainly is present in a supersaturated solution. The particles are consolidated and the Zr is precipitated as finely distributed dispersoids after a heat treatment at 300° to 450° C., and the alloy has an electrical conductivity of at least 58% IACS and a 10% softening temperature of at least 400° C. The consolidation may for instance be carried out by extrusion.

Journal ArticleDOI
TL;DR: In this article, the structural inhomogeneities and substructure evolution of can aluminium alloy 3004 after cold rolling by amounts ranging from 10% to 90% reduction has been examined by optical and transmission electron microscopy.

Journal ArticleDOI
TL;DR: In this paper, a procede d'extrusion semi-solide is described, a propositional et avantages du procede, des materiaux obtenus et avants du procedure.
Abstract: Description du procede d'extrusion semi-solide. Proprietes des materiaux obtenus et avantages du procede

Journal ArticleDOI
TL;DR: In this article, a planar Al-1%Si and Al-4%Cu films have been deposited over periodic oxide lines 1μm thick and valleys of 2 μm pitch.

Patent
23 Dec 1987
TL;DR: In this article, a metal layer is formed by sputtering while the wafer is heated to a temperature higher than that which produces a solid solution in the aluminium-based alloy.
Abstract: A method for forming a metal layer includes the steps of forming an insulation layer (62) having at least one step portion on a wafer (48, 61); and forming the metal layer (63) over the insulation layer. The metal layer is formed by depositing aluminium-based alloy by sputtering while the wafer is heated to a temperature higher than that which produces a solid solution in the aluminium-based alloy. As a result at the step portion, a good step coverage can be obtained and the surface of the aluminium alloy layer is planarized. At the same time, the method according to the present invention contributes to a prevention of deterioration in the quality of the layer by preventing the formation of a silicon rich layer adjacent the insulating layer with interferes with a subsequent patterning process. The method also enables the deposition process to be carried out at a later stage.

Journal ArticleDOI
TL;DR: In this paper, the tensile properties and wear resistance of SiC whisker-reinforced Al alloy 4032 composites were investigated, and the elastic modulus of T 6 heat treated SiC/4032 composite can be expressed as E(GPa) = 180Vf(vol pct) + 85.
Abstract: The tensile properties and wear resistance of SiC whisker-reinforced Al alloy 4032 composites were investigated. The elastic modulus of T 6 heat treated SiC/4032 composites can be expressed as E(GPa) = 180Vf(vol pct) + 85. The wear loss of SiC/4032 composites decreases rapidly with an increase in the volume fraction of SiC whisker up to 14 percent, beyond which it remains unchanged. The addition of BN gives rise to the degradation of the mechanical properties and of the coefficient of friction, which improves the wear resistance of the composites. The wear resistance of SiC/4032 composites depends remarkably on the size and distribution of Si particles in the Al alloy 4032 matrix. 20 references.

Proceedings ArticleDOI
TL;DR: In this article, the monotonic and cyclic strain-controlled fatigue tests were conducted at room temperature on several heat-treatable and non-heat-treating aluminum alloys of interest to the transportation industry.
Abstract: Monotonic and cyclic strain-controlled fatigue tests were conducted at room temperature on several heat-treatable and non-heat-treatable aluminum alloys of interest to the transportation industry. Extrusion, forging, plate, and sheet product-forms were tested. Various monotonic and cyclic fatigue properties are furnished, and the respective strain-life curves are compared. In general, materials with strong monotonic strain-hardening tendencies are also shown to exhibit marked cyclic hardening.

Journal ArticleDOI
TL;DR: In this article, the superplasticity of aluminium alloys containing magnesium, oint, iron and manganese as well as zirconium as a grain-refining addition element was investigated by high-temperature tensile tests.
Abstract: The superplasticity of aluminium alloys containing magnesium, oint, iron and manganese as well as zirconium as a grain-refining addition element was investigated by high-temperature tensile tests. The tool elongation and the strain rate sensitivity as a function of strain rate and temperature were determined. The activation enthalpy and activation volume were also determined in the superlastic region of the deformation. !n addition to the tensile tests metallo-graphic investigations were also made. The results obtained show that the superplasticity of the alloys investigated is increasing by the addition of iron but it is decreasing by the simultaneous addition of iron and manganese.

Journal ArticleDOI
TL;DR: In this article, solid-state diffusion bonded joints were produced between silver-coated clad Al-alloy sheets, based upon the systems Al-Zn-Mg (7010 alloy) and Al-Cu (2024 and Supral 220 alloys).
Abstract: Solid-state diffusion bonded joints were produced between silver-coated clad Al-alloy sheets. The alloys were based upon the systems Al-Zn-Mg (7010 alloy) and Al-Cu (2024 and Supral 220 alloys). The corresponding peel strengths of the joints in these alloys were 61, 45 and 42 N mm−1 in the solution heat treated state and 34, 12 and 48 N mm−1 in the aged state. At 480° C corresponding peel strengths were 2.4, 2.5 and 1.7 N mm−1. The mechanism of peel fracture in the peel test and the possibility of combining diffusion bonding with superplastic forming are discussed.

Journal ArticleDOI
TL;DR: In this article, a suspension of mica particles (40μm diameter and 3.7μ thick) obtained in a mechanically stirred Al-4 wt % Cu-1.5wt % Mg melt was poured and solidified in a variety of moulds under different heat flow configurations.
Abstract: A suspension of mica particles (40μm diameter and 3.7μ thick) obtained in a mechanically stirred Al-4 wt % Cu-1.5 wt % Mg melt was poured and solidified in a variety of moulds under different heat flow configurations. The resulting cast structure showed a non-uniform distribution of dispersed mica particles with mica-depleted and segregated zones due to their flotation before and during solidification. The experimentally observed profiles of mica-free regions deviate significantly from those computed on the basis of Stokes's law and freezing-time computations. In relatively thick castings, segregation of mica could be minimized by using low pouring temperatures and/or side as well as bottom chilling. It was found, however, that thin castings (12.5 mm) could easily be produced with a homogeneous distribution of mica particles.

Journal ArticleDOI
TL;DR: The high signal-to-noise ratio of the positive secondary lithium ion opens up the possibility of both high resolution imaging and microanalysis of lithium distributions in aluminium and other materials as discussed by the authors.
Abstract: SUMMARY Samples of aluminium-lithium alloys have been observed by scanning ion microscopy and analysed by secondary ion mass spectrometry. The high signal-to-noise ratio of the positive secondary lithium ion opens up the possibility of both high resolution imaging and microanalysis of lithium distributions in aluminium and other materials. Some of the problems encountered due to sample preparation are discussed and ion images of both the artefacts and the true lithium distribution are shown.