Top PDF THE APPLICATION OF Ni FOR IMPROVEMENT OF Al-Si-Fe ALLOYS

THE APPLICATION OF Ni FOR IMPROVEMENT OF Al-Si-Fe ALLOYS

THE APPLICATION OF Ni FOR IMPROVEMENT OF Al-Si-Fe ALLOYS

Life Cycle Assessment (LCA) is a scientific tool for the systematic evaluation of the environmental impacts of a product or service system through all stages of its life cycle “from cradle to grave“ (mining and extraction of raw materials, fabrication, transportation, use and recycling/ /disposal). The purpose of life cycle assessment is to define the scope of all environmental impacts associated with the product during its life cycle and to identify and reduce aspects with the most significant environmental impacts. Life Cycle Assessment is intended for broad use throughout the industry with a view to assess and stimulate environmental improvement in production processes and product development. Today, life cycle assessment is increasingly developed in metallurgy. It is related to new recycling technology, metal extraction from secondary materials and to fact, that metal production belongs mostly to large environmental pollution sources [1].
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Semisolid casting with ultrasonically melt-treated billets of Al-7mass%Si alloys

Semisolid casting with ultrasonically melt-treated billets of Al-7mass%Si alloys

to be more globular, which is convenient for thixocasting. After thixocasting with preheated billets, eutectic silicon plates are extremely refined due to the rapid solidification arising from low casting temperature. The tensile strength of thixocast samples with different iron contents does not change much even at 2mass% of iron, when thixocast with ultrasonically melt-treated billets. However, thixocast Al-7mass%Si-2mass%Fe alloy with non-treated billets exhibits an inferior strength of 80 MPa, compared with 180 MPa with ultrasonically melt-treated billets. The elongation is also improved by about a factor of two in thixocastings with ultrasonically melt-treated billets for all iron contents of Al-7mass%Si alloys, for example, the elongation of 11% in thixocast of Al-7mass%Si-0.5mass%Fe alloy with ultrasonically melt-treated billets, 5% in that with non-treated billets.
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Mat. Res.  vol.4 número1

Mat. Res. vol.4 número1

DSC analysis showed for the Fe-B-Zr-Cu a crystal- lization process that involves two clearly distinct phase transformations, for all the studied heating rates. Otherwise crystallization of Fe-B-Si-Ni-Mo samples followed differ- ent kinetics according to the applied heating rate: it exhibits multiple peaks for slow heating, and a single exothermal peak for heating rates equal or superior to 10 K/min. The obtained activation energies for the Fe-B-Zr-Cu alloy (362 and 301 kJ/mol) and for the Fe-B-Si-Ni-Mo alloy (323 kJ/mol) are comparable to reported values for amor- phous iron alloys. The values of the Avrami exponents for Fe-B-Zr-Cu (n = 1.0 and 1.2) and for Fe-B-Si-Ni-Mo (n = 1.0) are consistent with diffusion controlled crystal- lization processes with nucleation rates close to zero.
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Study of Mechanical and Wear Behaviour of Hyper-Eutectic Al-Si Automotive Alloy Through Fe, Ni and Cr Addition

Study of Mechanical and Wear Behaviour of Hyper-Eutectic Al-Si Automotive Alloy Through Fe, Ni and Cr Addition

base alloy increases the wear rate due to the formation of needle beta intermetallics. Ni addition to the alloy does not impede formation of needle-like intermetallic compounds and has no positive effect on the modification of microstructure. Introducing of Cr to the iron-rich alloy changes the beta intermetallics into the modified alpha phases and therefore reduced the detrimental effect of iron. As a result it recovers the strength and wear properties of the experimental alloy. Wear test surfaces were examined by SEM and have shown that Cr added alloy improves wear resistance through mild and smooth abrasive grooves filled with oxides.
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Development of environmentally friendly cast alloys and composites. High zinc Al-base cast alloys

Development of environmentally friendly cast alloys and composites. High zinc Al-base cast alloys

The castings production in Poland from M g-based and AlZn-based alloys is still very small as compared to the Fe ones, though Poland produces significant amount of pure zinc – Fig. 1, [3 – 7]. Recent efforts of the European Community are aimed, among others, at energy saving and improving environ- mental protection at the same time. From this point of view, foun- dry industry production should be focused on wider application of the alloys, which are less energy consumable during their melting process. Replacing some amount of Fe-based castings with the AlZn-based ones is very important for environmental protection, because they are relatively cheaper according to lower melting temperatures – Fig. 2, which allows saving energetic expenses.
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Statistical Assessment of the Effect of Chemical Composition on Mechanical Properties of Hypereutectic AlSi17CuNiMg Silumin

Statistical Assessment of the Effect of Chemical Composition on Mechanical Properties of Hypereutectic AlSi17CuNiMg Silumin

The above mentioned alloys were fabricated from the following starting materials (Table 1): aluminium in grade AR1 (99,96% Al), silicon of 98,5% purity (rest Fe and other elements), copper (99, 98% Cu), nickel (99, 98% Ni) and cast AG10 alloy (about 10 wt.% Mg). Melts were conducted in a Leybold-Heraeus IS5/III induction furnace with crucible of 0,7kg capacity made from magnesite refractory material. A protective coating of 2NaF and KCl was used. When the furnace temperature of ~ 820 o C had been reached, the melt was subjected to refining treatment with Rafglin-3 in an amount of 0,3 wt.%, followed by modification with Cu-P (~9,95%P). The temperature of pouring was controlled by a NiCr-NiAl TP-202K-800-1 thermocouple immersed in the bath of molten metal.
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Analytical Determining Of The Steinmetz Equivalent Diagram Elements Of Single-Phase Transformer

Analytical Determining Of The Steinmetz Equivalent Diagram Elements Of Single-Phase Transformer

Abstract: This article presents to an analytical calculation methodology of the Steinmetz Equivalent Diagram Elements applied to the prediction of Eddy current loss in a single-phase transformer. Based on the electrical circuit theory, the active and reactive powers consumed by the core are expressed analytically in function of the electromagnetic parameters as resistivity, permeability and the geometrical dimensions of the core. The proposed modeling approach is established with the duality parallel series. The equivalent diagram elements, empirically determined by Steinmetz, are analytically expressed using the expressions of the no loaded transformer consumptions. To verify the relevance of the model, validations both by simulations with different powers and measurements were carried out to determine the resistance and reactance of the core. The obtained results are in good agreement with the theoretical approach and the practical results.
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Braz. J. Phys.  vol.35 número3A

Braz. J. Phys. vol.35 número3A

The category of iron meteorites corresponds to about 5 % of the modern meteorite falls. In the study of Fe-Ni-bearing meteorites, there is a recent discussion about the formation of a low-moment Fe-rich γ phase which differs from the ordinary high-spin γ phase in the electronic structure and a lower lat- tice parameter, but has the same crystal structure, same degree of atomic order and same composition of ordinary taenite. In fact, this has been claimed to be a new mineral called anti- taenite which is common in slowly cooled meteorites [12-14]. This low-spin phase is proposed to occur in a thin epitaxial in- tergrowth with tetrataenite (ferromagnetic atomically ordered FeNi). Actually, metastable precipitates of this low-spin phase in a matrix of high-spin Fe-Ni phase of the same controlled composition have been synthetically produced near the Invar composition (≈ 35 at% Ni).
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The Current State of Neoadjuvant Chemotherapy for Muscle-Invasive Bladder Cancer

The Current State of Neoadjuvant Chemotherapy for Muscle-Invasive Bladder Cancer

NAC in patients with MIBC and the outcomes of randomised trials, the rate of patients receiving NAC has seen little increase. The reason for this low rate might be due to some concerns from urologists, such as delayed curative surgery treatment, and negative impact on peri and post- operative mortality and morbidity of chemotherapy. However, there is much evidence in the literature that show that NAC is not associated with these negative outcomes. Therefore, the rate of the use of NAC in patients with MIBC may increase in future.
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Modeling of Two-Stage Solidification: Part II Computational Verification of the Model

Modeling of Two-Stage Solidification: Part II Computational Verification of the Model

As we have already mentioned, the first stage is identical for both eutectic transformation modes. When the temperature drops below liquidus temperature, dendritic grains nucleate and grow. Computed solute distribution corresponding to this stage, for two macroscopic elements has been presented in Figure 1. It can be seen that diffusion layers of neighboring grains overlap in various time steps, depending on their mutual position. The contact of layers causes a decrease in growth velocity of envelopes. Thus, in these areas where solute diffusion layers do not overlap, envelopes are close to a sphere, whereas in the opposite situation, envelope segments are similar to Voronoi diagram. This reflects the two growth types introduced in the growth algorithm of dendritic envelopes.
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Evaluation of susceptibility of the ZRE1 alloy to hot cracking in conditions of forced strain

Evaluation of susceptibility of the ZRE1 alloy to hot cracking in conditions of forced strain

This work in combination with industrial tests of casting welding show that the causes of high-temperature brittleness are the partial tears of the structure and the hot cracks of both the castings and the welded and padded joints. Such phenomena should be treated as irreversible failures caused by the process of crystallisation that is in the area of co-existence of the solid and liquid structural constituent. The assessment of the resistance to hot fractures was conducted on the basis of the transvarestriant trial. The transvarestriant trial consists in changing of strain during welding It was stated that the range of the high-temperature brittleness is very broad, which significantly limits the application of the welding techniques to join or mend the elements made of alloy ZRE-1. The brittleness is caused mainly by metallurgical factors, i.e., precipitation of inter-metal phases from the solid solution.
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Evaluating the influence of selected parameters on sensitivity of a numerical model of solidification

Evaluating the influence of selected parameters on sensitivity of a numerical model of solidification

For every analyzed case it was assumed that in the range of variability of each parameter there are 4 points (p=4). The number of simulation needed to be conducted depends on the number of the studied physical model parameters k, as well as on how many times the matrix B* was created, and it is equal to r (k+1). Hence the number of computer simulations ranged between 80 for cases shown in Figures 3, 7, 8 and 9 through 128 and 320 for Figures 4 and 5 respectively, up to 640 for the case from Figure 6.

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Influence of tungsten and titanium on the structure of chromium cast iron

Influence of tungsten and titanium on the structure of chromium cast iron

The paper analyses the as-cast state structure of chromium cast iron designed for operation under harsh impact-abrasive conditions. In the process of chromium iron castings manufacture, very strong influence on the structure of this material have the parameters of the technological process. Among others, adding to the Fe-Cr-C alloy the alloying elements like tungsten and titanium leads to the formation of additional carbides in the structure of this cast iron, which may favourably affect the casting properties, including the resistance to abrasive wear.
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A Method To Find The Area Of Sector Without The Usage Of Angle Made By The Chord

A Method To Find The Area Of Sector Without The Usage Of Angle Made By The Chord

As we know that to find the area of sector the angle made by the chord (that is chord which divides the circle) is required. But in the below method we find the ratio of the segments of the circle. Thus by relating the area of segment to the area of sector the area of sector could be found. The ratio of area of segments is related to tangents that are drawn through diameter on either side.

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NICKEL INCORPORATION IN Fe(II, III) HYDROXYSULFATE GREEN RUST: EFFECT ON CRYSTAL LATTICE SPACING AND OXIDATION PRODUCTS

NICKEL INCORPORATION IN Fe(II, III) HYDROXYSULFATE GREEN RUST: EFFECT ON CRYSTAL LATTICE SPACING AND OXIDATION PRODUCTS

composition, oxidant, oxidation rate, and the dehydration degree and rate (Lin et al., 1996; Loyaux- Lawniczak et al., 2000). Refait & Génin (1997) prepared Ni(II)-Fe(II)-Fe(III) hydroxychloride LDHs by aerial oxidation of mixed Ni(II)-Fe(II)-hydroxides. They found that the final oxidation products depended on the initial Fe/Ni ratio. In the absence of Ni, green rust oxidized to lepidocrocite and the LDH structure was lost. For Fe/Ni > 5/3 both lepidocrocite and some Ni(II)-Fe(III) hydroxychloride were detected by X ray diffraction. For Fe/Ni between 1/3 and 5/3, only the hydroxychloride LDH was obtained. Since LDHs contain a mixture of divalent and trivalent cations in a brucite-like sheet, if enough Ni is present in divalent sites, the LDH structure is preserved on oxidation of structural Fe(II). In the current study we further investigated substitution of Ni(II) in sulfate GR2 and the oxidation products from exposure to air. The specific research objective is to determine the effect of Ni(II) incorporation on the GR2 crystal structure and to determine how Ni(II) affects the oxidation products by directly precipitating nickelous-GR2 from a mixture of Fe(II), Ni(II) and Fe(III) sulfate salts in anoxic conditions followed by aerial oxidation of the dried samples.
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CONTINUOUS CREATION IN THE PROBABILISTIC WORLD OF THE THEOLOGY OF CHANCE

CONTINUOUS CREATION IN THE PROBABILISTIC WORLD OF THE THEOLOGY OF CHANCE

The principle of divine control is very important in discussions con- cerning the relation between the Creator and His creatures. These seem to be based on two assumptions. The irst assumption is that God can achieve all His purposes in the created world (divine providence) if and only if He controls every existing being. Therefore, divine control must be perfect and unrestricted (divine volitions must be determined in every respect). Maximal possible control consists in the fact that God creates ex nihilo every being and subsequently conserves them. The second assumption is Anselmian: God is the greatest possible being one can conceive. A perfect being has everything under its control and a perfect being controls everything in the most perfect way possible. Furthermore, the best way to control everything is to create every being out of nothing and to create it as absolutely depen- dent in existence and nature upon God’s will. Omnipotence thus means to conserve continuously all created beings. Continuous creation is the best way to express divine perfection: perfect power and perfect will. Therefore, all contingent beings exist this or that way as long as divine power is acting and divine will wills itself to act upon a given being.
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Effect of heat treatment parameters on the properties of low-alloy cast steel with microadditions of vanadium

Effect of heat treatment parameters on the properties of low-alloy cast steel with microadditions of vanadium

This article examines the effect of prolonged time of holding at the temperature of 620 0 C on the processes of secondary phase precipitation and mechanical properties of low-alloy cast steel with an addition of vanadium subjected to two variants of heat treatment, i.e. U:1150 0 C+H:950 0 C+O:620 0 C and H:950 0 C+O:620 0 C. To determine an impact of the applied heat treatment operations, testing of mechanical properties and microstructural examinations of the cast steel with 0,21 and 0,27%C were carried out.
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Filtration of aluminum alloys and its influence on mechanical properties and shape of eutectical silicium

Filtration of aluminum alloys and its influence on mechanical properties and shape of eutectical silicium

Filtration during casting of high quality aluminum alloys belongs to main refining methods. Even when there are many years of experiences and experimental works on this subject, there are still some specific anomalies. While using ceramic filtration media during casting of aluminum alloys, almost in all experiments occurred increase of strength limit and atypical increase of extension. This anomaly was not explained with classical metallurgical methods, black-white contrast after surface etching neither with color surface etching. For that reason was used deep etching on REM. By using pressed ceramic filters, by studying morphology eutectical silicon was observed modification morphology of eutectical silicon, this explains increase extension after filtration. Pressed ceramic filters were used on experimental works. Casting was executed on hardenable alloy AlSi10MgMn.
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Buying Behavior Of Organic Vegetables Product The Effects Of Perceptions Of Quality And Risk

Buying Behavior Of Organic Vegetables Product The Effects Of Perceptions Of Quality And Risk

Quality is defined as the degree of excellence or superiority that an organization’s product possesses (Khan, 2005:28). Consumers judge or perceive the quality of the products and it also called perception of quality, because perception of quality derived from the analysis of consumers on product quality (Sanyal & Datta, 2011:605). Customer perceived value of product quality is a consumer opinion as ability of the product who suitable with expectation of consumer (Terenggana et al., 2013:326). Perception of quality is formed on consumers can be affected by several things including past experience, education, purchasing and consumer community (Yaseen et al., 2011:834), and perception of quality is important in improving the quality of products in the view of consumers (Parrol et al., 2013:603). Since knowledge and consumer needs change time by time, it taken an understanding related consumer perception of quality in evaluated to be known how big influence on purchase intention (Sanyal & Datta, 2011:607). Reviewing consumer behavior in foods, in previous research is often studied through perception of quality (Carrasco et al., 2012:1414). On last studied, perceived quality is the consumer’s judgment about a product’s overall excellence or superiority (Zeithaml, 1988). Meanwhile perceived quality is the judgment a consumer of product which refers to the physical characteristics of the product, and is related more to engineering and food technology (Carrasco et al., 2012). Several things that concern on perception of quality, first are spoke on the advantages related to the assessment of consumer products and the second on the technology applied to products that are both better than similar products. That matter is a critical element for consumer decision making, consequently, consumers will compare the
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The analysis of solidification process of ferritic-austenitic cast steel

The analysis of solidification process of ferritic-austenitic cast steel

It should be stressed that, according to the relationships given in Table 1, the solidification character of both of examined duplex cast steel compositions should be pure ferritic. The degree of segregation of the alloying elements resulting from the partition coefficients and empirically determined by EDX method [14], has confirmed the change of the solidification mechanism from pure ferritic to the ferritic-austenitic one only if the relationship (2) is employed. An addition of copper results in occurring the structural constituent of different morphology, which is Ȗ’ phase.
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