Showing papers on "Aluminium alloy published in 1980"

Deformation of fine-grained aluminium alloys

Abstract: The deformation of an ultrafine-grained aluminium alloy has been examined in tension and torsion. At grain sizes below about 3 μm the alloy exhibits inhomogeneous yielding but this is absent at larger grain sizes. If the lower yield strength values are plotted versus grain size the strengths are inversely dependent on grain size whereas the usual plot versus d −½ is non-linear and shows an enhanced strength at the finer grain sizes. However, if the inhomogeneous yielding region is avoided by extrapolating the work-hardening portion of the curve back to the elastic line, all the data can be well represented by the Hall–Petch relationship. Torsion tests, which allow the investigation of a large strain range, show that. the gredient of the grain size plots decreases slowly wIth strain but that the grain boundaries remain effective barriers to flow at strains up to at least 1.0. The deformation behaviour does not appear to agree with the current models for the influence of grain size on the flow stre...

Preparation of cast aluminium alloy-mica particle composites

Abstract: The optimum conditions for producing cast aluminium alloy-mica particle composites, by stirring mica particles (40 to 120 μm) in molten aluminium alloys (above their liquidus temperatures), followed by casting in permanent moulds, are described. Addition of magnesium either as pieces along with mica particles on the surface of the melts or as a previously added alloying element was found to be necessary to disperse appreciable quantities (1.5 to 2 wt.%) of mica particles in the melts and retain them as uniform dispersions in castings under the conditions of present investigation. These castings can be remelted and degassed with nitrogen at least once with the retention of about 80% mica particles in the castings. Electron probe micro-analysis of these cast composites showed that magnesium added to the surface of the melt along with mica has a tendency to segregate around the mica particles, apparently improving the dispersability for mica particles in liquid aluminium alloys.

Development of duplex deformation substructure during extrusion of a commercial Al-5Mg-0.8Mn alloy

Abstract: The microstructural changes which occur during the extrusion of a commercial aluminium alloy (AA 5456) have been investigated at macroscopic, microscopic, and substructural magnifications. Light microscopy has established that the deformation zone is not fully established until a short time after the peak or breakthrough pressure has occurred and that thereafter cylinder wall/billet shear is important in determining deformation. Light microscopy also reveals that recrystallized grains are present both at original grain boundaries and within grains when the deformation is advanced. Electron microscopy reveals that those grains contain a substructure and are thus dynamically recrystallized grains. The bulk of the material continues to deform with dynamic recovery as the operative mechanism. The deformation is thus duplex with dynamic recrystallization considerably modifying the structure normally observed in aluminium alloys. It is concluded that this occurs primarily because of the high solute addi...

Piston for an internal combustion engine and method for producing same

Abstract: The invention provides a piston formed by casting a metal piston body under pressure around an insert, the body being made of aluminium or aluminium alloy and the insert being made of a porous layer having a thickness 20 to 50 times the pore diameter and completely filled with the piston body metal which projects from the body into the pores of the insert.

Electrical inter-connection method

Abstract: To permit ball-bonding of wires of aluminium or aluminium alloy to small electrical circuits or components, a spark discharge is created between the end of the wire and an electrode in a shielding atmosphere with a peak current density in the wire section which is from 40 to 450 times that used for ball-bonding gold wire. In this way oxidation of the ball is prevented.

Fluidity of mica particle dispersed aluminium alloy

Abstract: Cast aluminium alloy-mica particle composites were made by dispersing mica particles in a vortex produced by stirring the liquid Al-4 wt% Cu-1.5 wt% Mg alloy and then casting the melt containing the suspended particles into permanent moulds. Spiral fluidity and casting fluidity of the alloy containing mica particles in suspension were determined. Both the spiral fluidity and the casting fluidity of the base alloy were found to decrease with an increase in volume or weight percent of mica particles (of a given size), and with a decrease in particle size (for a given amount of particles). The fluidities of Al-4 wt% Cu-1.5 wt% Mg alloys containing suspended mica particles were found to correlate very well with the surface area of suspended mica particles. The regression equation for spiral fluidity Y (cm) as a function of surface area of mica particles per gram of spiral X (cm2 g−1) at 700° C was found to be Y=42.62−0.42X with a correlation coefficient of 0.9634. The regression equations for casting fluidity Y′ (cm) as a functiono of surface area of mica particles per gram of fluidity test piece X′ (cm2 g−1) at 710 and 670° C were found to be Y′=19.71−0.17X′ and Y′=13.52−0.105X′ with correlation coefficients of 0.9194 and 0.9612 respectively. The percentage decrease in casting fluidity of composite melts containing up to 2.5 wt% mica with a drop in temperature is quite similar to the corresponding decrease in the casting fluidity of base alloy melts (without mica). The change in fluidity due to mica dispersions has been discussed in terms of changes in viscosity of the composite melts. However, the fluidities of these composite alloys containing up to 2.5 wt% mica are adequate for making a variety of simple castings including bearings for which these alloys have been developed.

Electrodeposition on Aluminium Alloys

Abstract: The technical requirements of electroplating on aluminium have been evaluated qualitatively by other authors for commercial purity aluminium only. Extension of these requirements to aluminium alloy...

Annealing behaviour of ion-implanted nickel-aluminium alloy

Abstract: The time evolution of the aluminium concentration profiles in ion-implanted nickel-aluminium alloys during annealing has been studied in the temperature range 550–800°C using the (p, γ) resonance broadening method. The surface enrichment of aluminium has been found to be balanced by a corresponding uniform decrease in the bulk concentration and hence the bulk concentration profiles can be described by the modified solution of the second diffusion equation, when the implanted concentration does not exceed the solubility limit. When the solubility limit is exceeded the time evolution follows the solubility controlled flow of the solutes. The dependence of the degree of surface enrichment on the extra irradiation of58Ni+ before and after the aluminium implantation is demonstrated and is found to be significant only in the post-irradiation cases. This is taken as evidence of the importance of interstitials in the development of the bulk concentration profiles. The linear Arrhenius plot extracted from the measurements indicates that the diffusion of A 1 in Ni can be described by the activation energyE=2.69 eV and the pre-exponential factorD0=0.6 cm2/s. Solid solubilities of aluminium in nickel from the implanted distribution are found to agree with those obtained using conventional metallographical methods.

Aluminium-magnesium-silicon alloy - esp. for use in mfg. aerosol containers by impact extrusion

Abstract: The alloy contains by wt 015-035% Si, 015-035% Mg, and less than, in each case:- 04% Fe; 001% Cu; 02%, esp 001% Cr; 02%, esp 01% Mn; 01%, esp 001% Zr; 005 each other element (OE) with a total of elements (OE) below 015% The alloy is used esp for mfg aerosol containers This alloy has a better combination of strength and ductility than the conventional A5 aluminium alloy when made into a container by impact extrusion of an annealed blank, eg a container 203 mm high with a wall thickness of 04 mm In an example, the alloy covered by the invention contained 03% Si, 034% Mg, 019% Fe, and 0017% Ti

Fatigue thereshold in a 2618a aluminium alloy

Abstract: — This work is concerned with the determination of the fatigue threshold ΔKth for an aluminium alloy. No dependency of ΔKth with grain size was observed. Crack closure concepts were applied in order to explain the effect of mean stress and environment. The opening load Pop was determined by the compliance method. Results show no significant variation of Pop with environment (air or vacuum) but partially explain the influence of mean stress on crack growth rates. Fractographic analysis (SEM) of fracture surfaces and evolution of compliance diagrams suggest that a change of mechanism in crack propagation occurs when stage I changes to stage II growth.

Method of manufacturing products from a copper containing aluminium alloy

Abstract: A 2000 series aluminum alloy characterized by high strength, high fatigue resistance, and high fracture toughness consists essentially of 4.2 to 4.7 percent copper, 1.3 to 1.8 percent magnesium, 0.8 to 1.3 percent manganese, 0.08 to 0.15 percent zirconium, maximums of 0.15 percent iron, 0.12 percent silicon, 0.25 percent zinc, 0.15 percent titanium, 0.10 percent chromium, 0.05 percent of each of any other trace elements present, and a maximum total of such other trace elements of 0.15 percent, the balance of the alloy being aluminum. The foregoing alloy is hot-worked and heat-treated to yield a final wrought product having a highly elongated and substantially unrecrystallized microstructure.

Process for the preparation of aluminium alloys

Abstract: Strontium-modified aluminium alloys may be produced by using strontium peroxide as the source of strontium. The strontium peroxide may be mixed with molten aluminium or molten aluminium alloy in a quantity sufficient to give the desired strontium metal content in the alloy being produced. The temperature of the molten aluminium or aluminium alloy with which the strontium peroxide is mixed is preferably at least 1000° C. The strontium peroxide alloys produced may be master alloys for use in the production of casting alloys, or may be casting alloys. Strontium acts as a grain refiner in such alloys.

Manufacturing method of cylinder made of aluminium alloy

Abstract: PURPOSE:To improve the function and quality of cylinders and improve productivity by sintering sintered powder integrally on the inner surface of thin steel plate from which cylinder liners are formed, and by manufacturing cylinders through setting a core in the hollow inside. CONSTITUTION:On the inner surface of thin steel plate 1, a sintered body 3 having sintered powder integrally is formed, and an opening 2 is formed which is to form an intake-exhaust scavenging port. The thin plate is formed into cylinder form by rolling shaping, and seam 5 is joined. Then, a core 7 is inserted into the cylinder- shaped body, and a core 8 which serves as an intake-exhaust scavenging port is arranged. After that, they are set in a metal mold not shown in the figure, and the molten alluminium alloy is poured into the mold, and aluminium alloy which is to form cylinder block 9 is fused into one.

Casting method of core material made of fiber to aluminium casting

Abstract: PURPOSE:To facilitate permeation of molten metal between fibers and improve the strength of products by generating heat in a core material through generation of induction current simultaneously making pouring while vibrating the core and thereby eliminating temperature difference between the surface of the core material and molten metal. CONSTITUTION:A core material 4 made of conductive fibrous material is positioned with a hanging wire 5 etc. at a specified position in a cavity 3 formed between two molds 1 and 2. A high frequency electromagnetic field is formed by connecting a coil 6 provided round the cavity 4 to an a.c. electric power source and energizing. Then, induced current is generated in the core material 4, and the core material 4 generates heat and vibrates. When molten aluminium alloy is poured under this condition, the core material 4 is cast firmly in the aluminium casting to increase the strength of the product.

Wear resistant aluminium alloy

Abstract: A wear resistant alloy of aluminium and an iron-based material. The alloy contains from 10% to 60% by volume of the iron-based material. The alloy has been created by very rapid surface heating of powder particles causing melting of the surface of the aluminium particles. The heating is produced by a shock wave pressure pulse. These surface regions are then very rapidly cooled by the rest of the particles so as to avoid chemical reactions between the aluminium particles and the particles of the iron-based material. The time at high temperature is of the order of a few microseconds at most.

Self load bearing roof element for buildings - has layer of insulating material sandwiched between pair of thin aluminium skins

Abstract: The element has an exterior skin resistant to corrosion and an interior skin or ceiling having the same transverse section, parallel to, and under the exterior skin. Both skins are made of precoated aluminium or aluminium alloy. Between the skins there is a continuous framework of metal profiles or plates extending from element edge to edge giving the element self load bearing properties. A pad of injected insulation material fills the space between the skins, and surrounds the frame, developing good qualities of adhesion and fire resistance.

Metal powder and process for its production

Abstract: The object is to provide a metal powder from which dense, compact and heat-resistant semi-finished products can be produced. For this purpose, sheets or sheet-like granules of an aluminium alloy whose alloying constituents are converted into a solid supersaturated solution by a high solidification rate in the order of magnitude of 10 to 10 DEG C are comminuted to a particle size below 100 mu m.

Mechanical Properties of Al-Mica Particulate Composite Material

Abstract: Cast aluminium alloy mica particle composites of varying mica content were tested in tension, compression, and impact. With 2.2 percent mica (size range 40µm – 120µm) the tensile and compression strengths of aluminium alloy decreased by 56 and 22 percent, respectively. The corresponding decreases in percent elongation and percent reduction are 49 and 39 percent. Previous work [2] shows that despite this decrease in strength the composite with 2.5 percent mica and having an UTS of 15 kg/mm2 and compression strength of 28 kg/mm2 performs well as a bearing material under severe running conditions. The differences in strength characteristics of cast aluminium-mica particle composites between tension and compression suggests that, as in cast iron, expansion of voids at the matrix particle interface may be the guiding mechanism of the deformation. SEM studies show that on the tensile fractured specimen surface, there are large voids at the particle matrix interface.

Formable aluminium alloy sheet product

Abstract: An aluminium sheet product is formed from an alloy containing Fe 0.6 - 1.0%, Si 0.5 - 0.9% and Cu 0.3 - 0.5% and incl ies Ti and B in conventional grain refining amount. Mn is permissible in amount up to 0.2 - 0.3% but is preferably held below 0.1%. The Mg impurity content is preferably held at a very low value so as to avoid difficulties with adhesion of lacquer. The principle use of the sheet product is for the production of bottle closures and for that purpose it is preferably produced in a thickness of 0.15 - 0.25 mm. and in a quality having a low percentage earing and fine grain size. For this purpose the sheet is subjected to a temper cold rolling reduction of 30 - 60% after the last inter-annealing treatment. No homogenisation treatment is required before hot reduction of the cast ingot and no precipitation heat-treatment is applied to the hot-rolled product before cold rolling.

Influence of Loading Direction and Environment on the SCC Susceptibility of Aluminium 7075–T651

Abstract: The influence of the loading direciion on the SCC susceptibility of aluminium alloy 7075–T611 has been investigated, the specimens having been tested by the constant strain rate method. The influence of the strain rate on the mechanical properties of the material was also investigated.The results confirm that this material is very susceptible to SCC when it is loaded in the ST-direction. In the LT- and L-directions it is susceptible only in acid environments (in the particular conditions of these tests). The influence of the environment (acidity, and chloride ion concentration) was also investigated, and a comparison made between several failure criteria which can be used to describe the SCC susceptibility in various environments.

Flow stress analysis of thermomechanically treated 2036 aluminium alloy

Abstract: The structure and mechanical properties of 2036 alloy deformed 30% at 423 and 473 K and aged at 423 K have been studied. The main precipitating phase was θ′; however, θ-phase was also observed in specimens deformed at 473 K and aged to peak at 423 K which results in a lower level of strength. A model developed by Kocks and Mulford using thermal activation theory to identify strengthening mechanisms in alloys was used to establish obstacles to flow in this alloy. It was found that in solution-treated and aged-to-peak specimens, the obstacles are θ′ precipitate particles which are athermal in nature. In thermomechanically treated specimens, they were uniformly distributed dislocations and θ′ precipitates. Since dislocations were stabilized by the precipitates, they also acted as athermal obstacles.