The Structure, Phase Composition and Rheological Properties of Powders Obtained by Chemical Dispersion of Al Alloys with Mo, V and Zr

2018 ◽  
Vol 284 ◽  
pp. 167-175
Author(s):  
A.Yu. Omarov ◽  
A.D. Shlyapin
Keyword(s):  
Heat Treatment ◽  
Phase Composition ◽  
Rheological Properties ◽  
Sodium Hydroxide Solution ◽  
Aqueous Sodium Hydroxide ◽  
Alkaline Solutions ◽  
Refractory Element ◽  
Alumina Ceramics ◽  
Chemical Dispersion ◽  
The Impact

Introduction of refractory elements into alumina ceramics to improve its properties, is usually carried out by mixing the alumina with oxides of refractory metals. In this work this problem has been solved by pre-alloying refractory element with aluminum and subsequent dispersion of alloy in aqueous alkaline solutions. Characteristics of microstructure, phase composition and rheological properties of powders obtained by chemical dispersion of alloys Al-Mo, Al-V and Al-Zr with 10 wt.% refractory element in 20% aqueous sodium hydroxide solution, as well as the impact of heat treatment at 1250 oC on these properties, have been discussed. On the basis of X-Ray analysis (XRA) and electron microscopy the conclusion was adopted that heat treatment of powder leads to significant phase and structural transformations of such powders and is a necessary stage of preparation for sintering.

Investigation of the Diffusion Processes at the Interface of the Cu/Ti Metal Composite

2016 ◽  
Vol 870 ◽  
pp. 239-242 ◽  
Author(s):  
Victor Georgievich Shmorgun ◽  
D.A. Evstropov ◽  
M.D. Trunov
Keyword(s):  
Heat Treatment ◽  
Phase Composition ◽  
Treatment Duration ◽  
Diffusion Processes ◽  
Explosion Welding ◽  
Metal Composite ◽  
Heat Treatment Duration ◽  
Hot Rolled ◽  
The Impact

In this study the impact of heat treatment on the structure of Ti/Cu laminated metal composite was investigated. The composite was fabricated via explosion welding and was subsequently hot rolled. Optical tests, SEM microscopy and microhardness tests were utilized to identify the phase composition and the structure of diffusion zones formed at the interface between metals during heat treatment. Heat treatment of the composite for less than 1 hour results in the formation of two interlayers with the Tiα+Ti2Cu and TiCu phase composition respectively. The increase in the heat treatment duration up to 10 hours results in the formation of two additional interlayers with the Ti3Cu4 and Cuα + βTiCu4 phase composition.

Microstructural and Mechanical Behaviour Evaluation of Mg-Al-Zn Alloy Friction Stir Welded Joint

2020 ◽  
Vol 17 (3) ◽  
pp. 8150-8159
Author(s):  
Kulwant Singh ◽  
Gurbhinder Singh ◽  
Harmeet Singh
Keyword(s):  
Heat Treatment ◽  
Friction Stir Welding ◽  
Magnesium Alloys ◽  
Mechanical Performance ◽  
Fuel Efficiency ◽  
Research Work ◽  
Grain Structure ◽  
Tensile Fracture ◽  
Friction Stir ◽  
The Impact

The weight reduction concept is most effective to reduce the emissions of greenhouse gases from vehicles, which also improves fuel efficiency. Amongst lightweight materials, magnesium alloys are attractive to the automotive sector as a structural material. Welding feasibility of magnesium alloys acts as an influential role in its usage for lightweight prospects. Friction stir welding (FSW) is an appropriate technique as compared to other welding techniques to join magnesium alloys. Field of friction stir welding is emerging in the current scenario. The friction stir welding technique has been selected to weld AZ91 magnesium alloys in the current research work. The microstructure and mechanical characteristics of the produced FSW butt joints have been investigated. Further, the influence of post welding heat treatment (at 260 °C for 1 h) on these properties has also been examined. Post welding heat treatment (PWHT) resulted in the improvement of the grain structure of weld zones which affected the mechanical performance of the joints. After heat treatment, the tensile strength and elongation of the joint increased by 12.6 % and 31.9 % respectively. It is proven that after PWHT, the microhardness of the stir zone reduced and a comparatively smoothened microhardness profile of the FSW joint obtained. No considerable variation in the location of the tensile fracture was witnessed after PWHT. The results show that the impact toughness of the weld joints further decreases after post welding heat treatment.

A Contribution to the Structure Characteristics and Phase Composition of Vanadium-Phosphorus Catalysts Prepared from the VOPO4.xH2O.yH3PO4 Precursor

1992 ◽  
Vol 57 (12) ◽  
pp. 2475-2480 ◽  
Author(s):  
Milan Brutovský ◽  
Štefan Gerej ◽  
Ján Novák ◽  
Lucia Ferdinandyová
Keyword(s):  
Heat Treatment ◽  
Phase Composition ◽  
Ir Spectra ◽  
Metal Cations ◽  
Preparation Procedure ◽  
Final Temperature ◽  
Structure Characteristics ◽  
Heat Treatment Regime ◽  
Condensed Phosphates ◽  
Defective Crystals

Catalysts were prepared from VOPO4.xH2O.yH3PO4 (x = 0.3-2, y = 0.2-0.85) by reduction with SO2 up to a final temperature of 750-800 °C, and activated in a reaction mixture of 1.0-1.4% butane in air up to 500 °C. The structure characteristics and phase composition of the catalysts were found to be affected by the preparation procedure and heat treatment regime. Their diffraction lines and IR spectra revealed that the catalysts from larger and less defective crystals than catalysts which were obtained from the VOHPO4.xH2O.yH3PO4 precursor and activated in the reaction mixture at temperatures up to 500 °C. In the catalysts prepared by the above procedure, the tendency to the formation of phases of higher-condensed phosphates, in particular VO(PO3)2 or even V(PO3)3, increases with increasing n(P):n(V) ratio and is then more pronounced than with vanadium-phosphorus catalysts prepared by other procedures. The tendency to the formation of the catalytically less active condensed phosphates is partly suppressed by the embedding of modifying metal cations (Fe or Cu in this case).

scholarly journals Zeolite Tuff and Recycled Ceramic Sanitary Ware Aggregate in Production of Concrete

2019 ◽  
Vol 11 (6) ◽  
pp. 1782 ◽  
Author(s):  
Jacek Szulej ◽  
Paweł Ogrodnik ◽  
Beata Klimek
Keyword(s):  
Phase Composition ◽  
Bimodal Distribution ◽  
Sanitary Ware ◽  
Ceramic Ware ◽  
Sieve Analysis ◽  
Production Plant ◽  
Concrete Production ◽  
Aluminous Cement ◽  
Ceramic Sanitary Ware ◽  
The Impact

The article presents the results of research on the use of ceramic ware waste as aggregate in concrete production. Four concrete mixtures with aluminous cement were prepared, each with a different admixture of clinoptilolite. The only used aggregate was crushed waste ceramic sanitary ware obtained from a Polish sanitary fixture production plant. As part of the studies, a compressive test of cubic samples at different curing times ranging from 7 to 90 days was performed. Prior to the preparation of the samples, a sieve analysis and an elemental analysis of the obtained aggregate were conducted. In the framework of the testing, the bimodal distribution of clinoptilolite grains was determined, as well as its chemical composition. The conducted compressive tests demonstrated high strength of concrete containing ceramic aggregate and aluminous cement with an addition of clinoptilolite. In order to determine the impact that adding zeolite exerts on the phase composition and the structure of concrete samples, an analysis of the phase composition (XRD) and scanning electron microscopy examination (SEM) were performed. Furthermore, tests of abrasion, water penetration under pressure and frost resistance were conducted, determining particular properties of the designed mixtures. The abrasion tests have confirmed that the mixtures are highly abrasion-resistant and can be used as a topcoat concrete layer. The conducted tests of selected properties have confirmed the possibility of using waste ceramic cullet and a mineral addition of clinoptilolite in concrete production.

scholarly journals Use of Multi-Anionic Sodium Tripolyphosphate to Enhance Dispersion of Concentrated Kaolin Slurries in Seawater

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1085
Author(s):  
Williams Leiva ◽  
Norman Toro ◽  
Pedro Robles ◽  
Edelmira Gálvez ◽  
Ricardo Ivan Jeldres
Keyword(s):  
Rheological Properties ◽  
Fine Particles ◽  
Sodium Tripolyphosphate ◽  
Mining Industry ◽  
Chord Length ◽  
Water Recovery ◽  
Reflectance Measurement ◽  
Anionic Charge ◽  
Free Environment ◽  
The Impact

This research aims to analyze the impact of sodium tripolyphosphate (STPP) as a rheological modifier of concentrated kaolin slurries in seawater at pH 8, which is characteristic of copper sulfide processing operations. The dispersion phenomenon was analyzed through chord length measurements using the focused beam reflectance measurement (FBRM) technique, complementing size distributions in unweighted and square-weighted modes. The reduction of the rheological properties was significant, decreasing from 231 Pa in a reagent-free environment to 80 Pa after the application of STPP. A frequency sweep in a linear viscoelastic regime indicated that by applying a characteristic dosage of 0.53 kg/t of STPP, the pulp before yielding increases its phase angle, which increases its liquid-like character. Measurements of the chord length verified the dispersion of particles, which showed an apparent increase in the proportion of fine particles and a reduction of the coarser aggregates when STPP was applied. Measurements of the zeta potential suggested that the high anionic charge of the reagent (pentavalent) increases the electrostatic repulsions between particles, overcoming the effect of cations in seawater. The results are relevant for the mining industry, especially when the deposits have high contents of complex gangues, such as clays, that increase the rheological properties. This increases the energy costs and water consumption needed for pumping the tailings from thickeners to the tailing storages facilities. The strategies that allow for the improvement of the fluidity and deformation of the tailings generate slack in order to maximize water recovery in the thickening stages.

scholarly journals Impact of the Simulated Gastric Digestion Methodology on the In Vitro Intestinal Proteolysis and Lipolysis of Emulsion Gels

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 321
Author(s):  
Camila Mella ◽  
Michelle Quilaqueo ◽  
Rommy N. Zúñiga ◽  
Elizabeth Troncoso
Keyword(s):  
Heat Treatment ◽  
Protein Isolate ◽  
Gastric Digestion ◽  
Human Gastrointestinal Tract ◽  
Gel Structure ◽  
Intestinal Digestion ◽  
Food Digestion ◽  
The Impact ◽  
Digestion Methods

The aim of this work was to study the impact of the methodology of in vitro gastric digestion (i.e., in terms of motility exerted and presence of gastric emptying) and gel structure on the degree of intestinal proteolysis and lipolysis of emulsion gels stabilized by whey protein isolate. Emulsions were prepared at pH 4.0 and 7.0 using two homogenization pressures (500 and 1000 bar) and then the emulsions were gelled by heat treatment. These gels were characterized in terms of texture analysis, and then were subjected to one of the following gastric digestion methods: in vitro mechanical gastric system (IMGS) or in vitro gastric digestion in a stirred beaker (SBg). After gastric digestion, the samples were subjected to in vitro intestinal digestion in a stirred beaker (SBi). Hardness, cohesiveness, and chewiness were significantly higher in gels at pH 7.0. The degree of proteolysis was higher in samples digested by IMGS–SBi (7–21%) than SBg–SBi (3–5%), regardless of the gel’s pH. For SBg–SBi, the degree of proteolysis was not affected by pH, but when operating the IMGS, higher hydrolysis values were obtained for gels at pH 7.0 (15–21%) than pH 4.0 (7–13%). Additionally, the percentage of free fatty acids (%FFA) released was reduced by 47.9% in samples digested in the IMGS–SBi. For the methodology SBg–SBi, the %FFA was not affected by the pH, but in the IMGS, higher values were obtained for gels at pH 4.0 (28–30%) than pH 7.0 (15–19%). Our findings demonstrate the importance of choosing representative methods to simulate food digestion in the human gastrointestinal tract and their subsequent impact on nutrient bioaccessibility.

scholarly journals Effect of Heat Treatment by the Sous-Vide Method on the Quality of Poultry Meat

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1610
Author(s):  
Wiesław Przybylski ◽  
Danuta Jaworska ◽  
Katarzyna Kajak-Siemaszko ◽  
Piotr Sałek ◽  
Kacper Pakuła
Keyword(s):  
Heat Treatment ◽  
Sensory Quality ◽  
Treatment Method ◽  
Poultry Meat ◽  
Chicken Breast ◽  
Breast Meat ◽  
Sous Vide ◽  
The Impact ◽  
Cooked Meat

An increase in the consumption of poultry meat has been observed due to its availability, nutritional value, and delicate flavor. These characteristics make it possible to prepare, with the use of spices and other additives, many different dishes and products for increasingly demanding consumers. The sous-vide technique is increasingly being used to give new sensory attributes to dishes in gastronomy. The study aimed to assess the impact of the heat treatment method, i.e., the sous-vide method, as compared to traditional cooking, on the sensory quality of poultry meat, as well as the efficiency of the process with regard to technological quality. The cooking yield with the sous-vide method of processing poultry meat was higher than with the traditional method of cooking in water (88.5% vs. 71.0%, respectively). The meat was also found to be redder (a* = 254 vs. 074) and less yellow (b* = 1512 vs. 1649), as well as more tender. The sensory quality of chicken breast meat obtained by the sous-vide method was higher in terms of attributes such as color tone, tenderness, juiciness, and overall quality. At the same time, it was lower in terms of the odor of cooked meat and the flavor of cooked meat as compared to meat subjected to traditional cooking.

scholarly journals The effect of heat treatment and impact angle on the erosion behavior of nickel-tungsten carbide cold spray coating using response surface methodology

2021 ◽  
Author(s):  
Marios Kazasidis ◽  
Elisa Verna ◽  
Shuo Yin ◽  
Rocco Lupoi
Keyword(s):  
Heat Treatment ◽  
Response Surface Methodology ◽  
Mass Loss ◽  
Tungsten Carbide ◽  
Response Surface ◽  
Spray Coating ◽  
Impact Angle ◽  
Control Factors ◽  
Heat Treated ◽  
The Impact

AbstractThis study elucidates the performance of cold-sprayed tungsten carbide-nickel coating against solid particle impingement erosion using alumina (corundum) particles. After the coating fabrication, part of the specimens followed two different annealing heat treatment cycles with peak temperatures of 600 °C and 800 °C. The coatings were examined in terms of microstructure in the as-sprayed (AS) and the two heat-treated conditions (HT1, HT2). Subsequently, the erosion tests were carried out using design of experiments with two control factors and two replicate measurements in each case. The effect of the heat treatment on the mass loss of the coatings was investigated at the three levels (AS, HT1, HT2), as well as the impact angle of the erodents (30°, 60°, 90°). Finally, the response surface methodology (RSM) was applied to analyze and optimize the results, building the mathematical models that relate the significant variables and their interactions to the output response (mass loss) for each coating condition. The obtained results demonstrated that erosion minimization was achieved when the coating was heat treated at 600 °C and the angle was 90°.

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