AI Alloy Research Articles

PENGARUH TEMPERATUR TUANG DENGAN JENIS MATERIAL PADUAN Al RONGSOK (KAMPAS REM PANCI) TERHADAP POROSITAS, KEKERASAN DAN STRUKTUR MIKRO HASIL PENGECORAN EVAPORATIVE

Recycling is a way of processing used materials that is started with selection, collection, then the process of foundry to create a new product that is more valuable economical. The objective of this research is to know the effect of casting temperature with the kind of guide material AI alloy junk from brake shoe and pan on porosity, hardness, microstructure (the evaporative foundry result). The recycling of used aluminum is an alternative to reduce the waste material from aluminum. Casting temperature is an variable that can effect the result of foundry where if the casting temperature is low, then there will be a quick freeze before the mold is completely filled. And if the casting temperature is too high, then shrinkage can occur and the porosity value may increase. This research used four casting temperature variations, namely: 650°C, 700°C, 750°C, and 800°C. The evaporative foundry method uses styrofoam pattern that is piled up into sand mold. The metal that is casted will form like styrofoam pattern. The result of casting temperature testing can effect on porosity, hardness, and microstructure.

PENGARUH TEMPERATUR TUANG DENGAN JENIS MATERIAL Al PADUAN (RONGSOK WAJAN) TERHADAP KEKERASAN HASIL PENGECORAN EVAPORATIVE

The objective of this research is to know the effect of casting temperature with the kind of guide material AI alloy junk from pan on hardness (the evaporative foundry result). The recycling of used aluminum is an alternative to reduce the waste material from aluminum. Recycling is a way of processing used materials that is started with selection, collection, then the process of foundry to create a new product that is more valuable economical. Casting temperature is an variable that can effect the result of foundry where if the casting temperature is low, then there will be a quick freeze before the mold is completely filled. And if the casting temperature is too high, then shrinkage can occur anditheiporosity value may increase. This research used four casting temperature variations, namely: 650°C, 700°C, 750°C, and 800°C. The evaporative foundry method uses styrofoam pattern that is piled up into sand mold. The metal that is casted will form like styrofoam pattern. The resultiof casting temperature testing can effect on hardness.

Growth of AlN by Reactive Gas Injection of Nitrogen in an AlMg Matrix

The primary objective of the present research was to provide a fundamental understanding of the processing science necessary to fabricate the Aluminum Nitride (AIN) reinforced Aluminum-Magnesium (AIMg) composites via Reactive Gas (N2) Injection in the AIMg alloy melt. Aluminum nitride (AlN) matrix composites were prepared by a novel approach. It was possible to produce a considerable amount of AIN particles in the AI alloy matrix at a reaction temperature as low as 900 °C utilizing the in-situ nitration reaction process developed in the present study. The volume fraction of AIN increases almost linearly with increasing the magnesium (Mg) content in the alloy and the reaction time. The shapes of AIN particles were found to have different forms, whose sizes were in the range from submicron to a few microns. From the present study, it is concluded that the new innovative in-situ nitridation process developed in the present study can be successfully applied for processing of high strength AIMg/AIN composites. For particles and composite structure characterization some methods were used, including: scanning microscopy, quantitative analysis of selected composite regions and XRD analyses. Composite structure and reinforcement distribution was compared with use of quantitative analysis. Morphology and diffraction pattern of aluminum nitride particles was shown. Typical structure of studied composites with microanalysis results was indicated. Aluminum nitride dispersion change was represented.

Surface Integrity Investigations in Ball Burnishing of 6063 AI Alloy

The paper reports an experimental investigation on surface roughness and degree of work hardening beneath the burnished surface of 6063 Al alloy. The experiments were conducted using Taguchi design with an L18 (2 1 x3 7 ) orthogonal array (OA). ANOVA of the experimental result shows that the ball material is the significant factor influencing surface roughness. HCHC ball was influential in reducing surface roughness significantly. It is found that surface roughness decreases with an increase in burnishing feed and at moderate depth of penetration. Coconut oil as a lubricant improved the surface finish compared to other lubricants. Percentage degree of work hardening was low at 100 m m depth. Feed is the significant parameter influencing percent degree of work hardening. Next influencing parameter is speed. Stainless steel ball is more influential in reducing percent degree of work hardening of the burnished specimen.

Friction Stir Welding of Al Alloy Thin Plate by Rotational Tool without Pin

For friction stir welding (FSW), a new idea is put forward in this paper to weld the thin plate of AI alloy by using the rotational tool without pin. The experiments of FSW are carried out by using the tools with inner-concave-flute shoulder, concentric-circles -flute shoulder and three-spiral-flute shoulder, respectively. The experimental results show that the grain size in weld nugget zone attained by the tool with three-spiral-flute shoulder is nearly the same while the grain sizes decrease with the decrease of welding velocity. The displacement of material flow in the heat-mechanical affected zone by the tool with three-spiral-flute shoulder is much larger than that by the tool with inner-concave-flute shoulder or concentric-circles-flute shoulder. The above-mentioned results are verified by numerical simulation. For the tool with three-spiral-flute shoulder, the tensile strength of FSW joint increases with the decrease of welding velocity while the value of tensile strength attained by the welding velocity of 20 mm/min and the rotation speed of 1800 r/min is about 398 MPa, which is 80% more than that of parent mental tensile strength. Those verify that the tool with three-spiral-flute shoulder can be used to join the thin plate of AI alloy.

Raney Ni–Al alloy-mediated reduction of benzils in water

Raney Ni–AI alloy in a dilute aqueous alkaline solution has been shown to be a powerful reducing agent and is highly effective for the reduction of alkylbenzils and alkoxybenzils to afford the corresponding 1,2-diarylethers at 90°C, in the absence of organic solvents. 4,4′-Dinitrobenzil was transformed selectively to 1,2-bis(4-aminophenyl)-ethane.

Effect of process parameters on bond formation during ultrasonic consolidation of aluminum alloy 3003

Ultrasonic consolidation (UC) is a novel additive manufacturing process wherein three-dimensional metallic objects are fabricated layer by layer in an automated fashion from thin metal foils. The process has immense potential for fabrication of injection molding tooling with conformai cooling channels, fiber-reinforced composites, multi-material structures, smart structures, and others. The proportion of bonded area in relation to the total interface length, termed linear weld density (LWD), is perhaps the most important quality attribute of UC parts. A high level of LWD is desirable in parts intended for load-bearing structural applications. It is therefore necessary to understand what factors influence LWD and devise methods to enhance bond formation during ultrasonic consolidation. The current work elucidates the effects of process parameters on LWD in AI alloy 3003 UC parts. A set of optimum parameters for AI 3003 part fabrication using UC has been obtained, which may vary, however, for different foil materials and sonotrode/foil fric-tional conditions. The beneficial effects of using elevated substrate temperatures and its implications on overall manufacturing flexibility and the trade-offs between part quality and build time are discussed. The mechanism of ultrasonic welding is discussed based on oxide layer removal and plastic deformation at the weld interface. A preliminary understanding of defect formation during UC is presented, based on which a method (involving surface machining) for obtaining near-100% LWD is demonstrated. The findings of the current work encourage wider utilization of the UC process and could stimulate further research in the areas of UC process development and modeling.

방열판 직접압출공정의 성형성 향상에 관한 연구

At present, the design of extrusion dies and operation in extrusion companies are primarily based on trial and error. The experience of the die designer, the press operator and the die corrector determine the performance of the extrusion die and the efficiency of the process. In order to produce defect-free products of desirable quality in terms of strength, surface quality and geometrical dimensions, it is important to obtain more knowledge of the processes that occur during extrusion. Recently, to reduce the costs of designing and manufacturing of extrusion dies, and to ensure the quality of the extruded products, numerical simulation for extrusion processes such as FEM (finite element method) is applied increasingly and becomes a very important tool for the design and development of new products. However, most of the studies about FE simulation have been accomplished for simple geometry and low extrusion ratio in the filed of steady metal flow conditions. The extruded products of AI alloy in industrial practice involve complicated sectional geometry. This study was designed to reduce the time of die design and manufacturing in the extrusion process using FEM simulation. FEM simulations of extrusion process were performed in non-steady states conditions by changing weld plate included in extrusion die set. Product which was employed in this study is heat sink that has been used in the parts of heat exchanger of electric circuits. It is generally applied for aluminum or its alloys due to heat efficiency and easy production of complicated shapes, and manufactured by extrusion process. The simulated results showed that weld plate shape in extrusion dies influences meta] flow and dimensional accuracy of products.

Wear mechanism maps for metal matrix composites

Empirical wear transition maps have been constructed to delineate the load velocity conditions under which wear transitions occurred in an A356 AI alloy and an A356 Al20%SiC composite. Experiments were performed in dry sliding conditions, using a block-on-ring (SAE 52100) configuration, within a load range of 0.2–400 N and a sliding velocity range of 0.2–5.0 m s −1. Both materials displayed transitions from mild to severe wear at specific load and sliding velocity combinations. The mild wear regime for the composite was expanded to a higher range of sliding speeds and loads by comparison with unreinforced A356 Al. Within the mild regime, two sub-regimes existed for both materials, namely where mixing/oxidation occurred at low sliding speeds to produce a thermally insulating surface layer, and another at higher speeds where this layer was removed. In the composite an additional wear transition, i.e. from mild to ultra-mild regime, occurred at low loads and velocities where the wear rates of the composite were at least two orders of magnitude lower than unreinforced A356 Al, due to the load supporting effect of the particles at the contact surfaces. In both materials, the transition from mild to severe wear occurred at conditions where the surface (bulk) temperature exceeded a critical value of approximately 125 °C in the A356 Al and 338 °C for the composite. The temperature data were summarised in the form of surface temperature maps on log load versus log velocity axes. Wear mechanisms in each regime were determined using scanning electron microscopy, and energy dispersive spectroscopy techniques that were used to analyse morphologies, microstructures and chemical compositions of worm surfaces and wear debris. The dominant mechanisms in each regime were identified and correlated with wear rate and temperature map data to summarise the effects of reinforcement on wear rates and transitions.

放電プラズマ焼結法による高Ｓｉ‐Ａｌ粉末の焼結過程と機械的性質

Spark plasma sintering (SPS) method has been applied for the consolidation and sintering of argon gas atomized powder of Al-25mass%Si-3.5%Fe-3.5%Ni-1%Mg alloy. Through this experiments, firstly, we investigated the sintering process of SPS method for Al alloy powder by means of optical microscopy, scanning electron microscopy and X-ray diffraction. Secondly, we investigated the mechanical properties of near-net-shape formed AI alloy powder by SPS method. Results obtained were as follows:(1) At the sintering process of SPS, the sample temperature rose faster and it was kept 10 K higher than the temperature of die. After shut off the electric power, sample temperature goes down faster than that of die.(2) At the very early step of SPS process, each particle of Al alloy gather to dense by slipping and deformation. When sample temperature is up to 650-660 K, necking of particles is formed.(3) Tensile strength of SPSed compacts is 235 N/mm2, however, this value is increased up to 285 N/mm2 by heat treatment.

Superplastic Deformation of Zn-2wt%AI Alloy under Cyclic Complex Loading Conditions

Superplastic Deformation of Zn-2wt%AI Alloy under Cyclic Complex Loading Conditions

Ni3Al and Ni3Si-based intermetallics produced by the Osprey process

Four NiAlbased and two NiSiTibased intermetallic compounds were spray-deposited using a nitrogen gas for atomization. The impurity contents, relative densities and microstructures of the alloys were investigated in the as-deposited condition.The oxygen content of the alloys varied from 20 to 90 ppm, and the nitrogen content ranged from 10 ppm in a binary Ni 3 AI compound to 90 ppm in NiAlCrFe alloy and to 150 ppm in the case of NiSiTi. No sign of nitrides or oxides was observed. The relative density of the alloys was higher than 99% and the majority of pores located at grain boundaries. The chromium free NiAI alloy had a single-phase, equiaxed and recrystallized structure (γ′), while the chromium containing NiAI alloys had a γ γ′ multiphase structure with 5–20% volume fraction of the disordered γ phase. The γ phase formed a network or a bimodal mixture of network and lamellar structures in the ordered γ′ matrix. The NiSiTi alloys showed a cell structure with cell interiors consisting of γ γ′ network structure and cell borders of the ordered γ′ phase. The mechanical properties were comparable with those of the previously spray-deposited Ni 3 Al-based alloys or with those of the NiSiTi based alloys of the present type.

Characterization of microstructural damage during plastic strain of a particulate-reinforced metal matrix composite at elevated temperature

The evolution of damage in a SiC-reinforced 2618 AI alloy during plastic strain has been investigated by elastic modulus reduction and direct observations of the microstructure at room temperature and temperatures up to 220 °C. Particle fracture increases as a function of strain at all temperatures but the total number of fractured particles at any given strain is lower at higher test temperatures. The dependence of fracture on particle size and aspect ratio was recorded. Normalized elastic modulus measurements decrease as a function of strain at the same rate for tests at 25,110 and 220 °C with an anomalous set of measurements at 165 °C showing a reduced damage rate. There is no universal correlation between the number of damaged particles and reduced modulus with each test temperature showing a different relation. This indicates the different temperature dependence of void nucleation and subsequent growth. The results are used to interpret different models of load sharing between reinforcement and matrix during straining.[/p]

Effect of prestrain on the superplastic behaviour of a fine grained 7475 AI alloy

The effect of prestraining at a fast strain rate (region III) on the subsequent superplastic behaviour (region II) of a 7475 AI alloy has been studied. The results show that prestraining causes a decrease in the elongation to failure as compared to the non-prestrained (as-received) samples. This decrease in elongation is postulated to be associated with the growth of cavities formed during prestraining as well as grain growth during deformation in region II. Prestraining in region III did not lead to any observable inhomogeneities in strain distribution during subsequent deformation.

Crystal structure and morphology of AIN precipitating on nitriding of an Fe-2at.% Al alloy

Abstract The crystallography of aluminium nitride precipitating on nitriding of an Fe-2at.% AI alloy has been investigated by electron microscopy and by X-ray diffraction. The precipitation of AIN can be described as a classical nucleation and growth process; no evidence has been obtained for clustering of alloying element atoms or other pre-precipitation phenomena. Two modes of AIN precipitation have been observed depending on the initial deformation state of the specimens: (i) in cold-rolled specimens, precipitation of cubic (rock salt) AIN particles with platelet-type morphology exhibiting a Bain orientation relationship with the α-Fe matrix, and (ii) in recrystallized specimens, precipitation of hexagonal (wurtzite) AIN particles without specific morphology and, for a significant part exhibiting a Pitsch-Schrader orientation relationship with the α-Fe matrix. A small fraction of cubic (rock salt) AIN also occurs in the recrystallized specimens. Although the hexagonal (wurtzite) crystal structure of AI...

Damping behavior of discontinuously reinforced ai alloy metal-matrix composites

High damping materials allow undesirable mechanical vibration and wave propagation to be passively suppressed. This proves valuable in the control of noise and the enhancement of vehicle and instrument stability. Accordingly, the scientific community is continually working toward the development of high damping metals (hidamets) and high damping metal-matrix composites (MMCs). The MMCs are particularly attractive in weight-critical applications when the matrix and reinforcement phases are combined to provide desirable property combinations, such as high damping and low density. Inspection of the available scientific literature, however, reveals that an understanding of the precise correlation between the presence of secondary phases (either reinforcements or precipitates) and material damping has eluded investigators, partly as a result of the superposition of multiple mechanisms. As a step toward the clarification of damping phenomena in discontinuously reinforced MMCs, this article describes the damping behavior and mechanisms that are present in discontinuously reinforced MMCs, with particular emphasis on particulate-reinforced Al alloy MMCs processed using spray atomization and deposition. The operative damping mechanisms in the particulate-rein-forced MMCs are discussed in light of the data obtained from microstructural studies and damping capacity measurements.

Dry sliding wear of Al alloy 2024-Al 20 3 particle metal matrix composites

In the present investigation, Al 2024-15vol.%Al 20 3 particulate (average size, 18 μm) composites were fabricated using the liquid metallurgy route. The wear and friction characteristics of AI alloy 2024 and Al 2024-15vol.%Al 20 3p composite in the as-extruded and peak-aged conditions were studied using a pin-on-disc machine (with a steel disc as the counterface material). The worn surfaces, subsurfaces and the debris were analysed in a scanning electron microscope. The performance of the composite in the as-extruded condition is slightly inferior to that of the unreinforced alloy. However, in the T6 condition, although the wear rates of two materials are initially comparable, the unreinforced alloy seizes while the composite does not within the tested range employed. In the as-extruded condition, the presence of A1 20 3 particles is not particularly beneficial as they fracture and result in extensive localized cracking and removal of material from the surface. In the peak-aged condition, however, while the unreinforced alloy exhibits severe plastic deformation and undergoes seizure, there is no significant change in the mechanism in the case of the composite. Except in the case of the peak-aged unreinforced alloy, worn surfaces of all other materials show the presence of an iron-rich layer.

Microstructural Characterization of Al-.5Cu AND Al-1Si ON 0.6nm TCA-SiO2/Si Following Heat Treatment at 400°C in N2 - Mechanisms Providing Stability and A High Break Down Voltage for The Al-.5Cu Mos Device

ABSTRACTAl-.5Cu is used as an interconnect conductor in ultra large scale integration (ULSI) devices. The specific use investigated in this study is as a gate electrode deposited directly on extremely thin 6 nm TCA SiO2. Changes in microstructure and reactions between the AI-.5Cu and SiO2 following heat treatment were characterized using analytical electron microscopy. When Al-iSi or AI-.5Cu are used as gate electrodes in a metal oxide Si field effect transistor (MOSFET) a conducting diffusion barrier layer of TiN or heavily doped poly-Si is usually deposited between the AI alloy and the SiO2. The addition of this relatively high resistivity barrier layer increases the power consumption of a MOSFET constructed with this gate electrode, increases the operating voltage necessary and decreases the frequency at which the MOSFET can be switched.1 An Al-.5Cu metal oxide silicon (MOS) device maintained a high break down voltage without a diffusion barrier following heat treatment by forming an Al-Cu intermetallic at the silica/metal interface.

On the failure mode in a 7475 AI alloy

On the failure mode in a 7475 AI alloy

Ｆｅ‐Ａｌ合金を結合相にした超硬合金の作製

WC-8.6mass%Fe-1.4mass%Al and WC-6.7mass%Fe-3.3mass%Al alloys were prepared by sintering of wet-mixed powder of WC, Fe and AI at 1713K for 2.4ksec in a vacuum and then their hot isostatic pressing.The evaporation of 13% Al from WC-Fe-Al alloys have been observed in the fabricating process. The sintered WC-Fe-Al alloys have a fine microstructure. Especially, the WC-8.6mass%Fe-1.4mass%AI alloy, which has a few pores after sintering at 1713K, has 1.8GPa of TRS and 92.5HRA of hardness. Furthermore, the increase in weight due to oxidation in this alloy is about one half that of the conventional WC-12mass%Co alloy.