scholarly journals Mathematical modelling of joint reliability indicators taking into account complex formation of surface quality metrics and physical and mechanical properties of functional surface materials

2021 ◽  
Vol 2131 (5) ◽  
pp. 052024
Author(s):  
E A Polsky ◽  
S V Sorokin ◽  
V M Shemenkov

Abstract The article deals with the problems of engineering support of the main indicators of reliability (durability) for the shape elements of molds. The influence of geometric, physico-mechanical, and physico-chemical parameters of surface quality on the formation of the required service characteristics of mating parts that ensure the established operating time of the product for failure is studied. The results of the influence of ion-plasma treatment on the structure and phase composition are presented: 1.2344 and 1.2379 tool steels (DIN). It is evaluated that the glow discharge treatment leads to the erosion of the fingerprints, appearing in the process of nitriding of this type of steel and it also causes thickening of defects in the matrix phase α-Fe together with fine grading CrN, as well as the dispersion of carbide inclusions and their uniform distribution in the surface layer to a depth of up to 80 microns, resulting in the increase of the microhardness of the surface by 15 - 18 %.

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 295
Author(s):  
Asma Yakdhane ◽  
Sabrine Labidi ◽  
Donia Chaabane ◽  
Anita Tolnay ◽  
Arijit Nath ◽  
...  

Microencapsulation is a well-known technology for the lipid delivery system. It prevents the oxidation of fatty acids and maintains the quality of lipid after extraction from oil seed and processing. In flaxseed oil, the amount of ω-3 and ω-6 polyunsaturated fatty acids are 39.90–60.42% and 12.25–17.44%, respectively. A comprehensive review article on the microencapsulation of flaxseed oil has not been published yet. Realizing the great advantages of flaxseed oil, information about different technologies related to the microencapsulation of flaxseed oil and their characteristics are discussed in a comprehensive way, in this review article. To prepare the microcapsule of flaxseed oil, an emulsion of oil-water is performed along with a wall material (matrix), followed by drying with a spray-dryer or freeze-dryer. Different matrices, such as plant and animal-based proteins, maltodextrin, gum Arabic, and modified starch are used for the encapsulation of flaxseed oil. In some cases, emulsifiers, such as Tween 80 and soya lecithin are used to prepare flaxseed oil microcapsules. Physico-chemical and bio-chemical characteristics of flaxseed oil microcapsules depend on process parameters, ratio of oil and matrix, and characteristics of the matrix. As an example, the size of the microcapsule, prepared with spray-drying and freeze-drying ranges between 10–400 and 20–5000 μm, respectively. It may be considered that the comprehensive information on the encapsulation of flaxseed oil will boost the development of functional foods and biopharmaceuticals.


2016 ◽  
Vol 25 (5-6) ◽  
pp. 165-169
Author(s):  
C. Rajaravi ◽  
P.R. Lakshminarayanan

AbstractThe paper describes a different condition of pouring temperature by sand and permanent mould to produce A356-6 wt% TiB2 metal matrix composites by in-situ method salt metal reaction route. The observation of SEM micrographs shows particle distribution of the TiB2 and it appears in hexagonal shape in Al matrix. The results of X-ray diffraction (XRD) analysis confirmed the formation of those TiB2 particulates and the results showed TiB2 particles are homogeneously dispersed throughout the matrix metal. Subsequent structure-property evaluation studies indicated sub-micron size reinforcement of in-situ formed TiB2 particles with improved physical and mechanical properties as compared to sand and permanent mould of Al-TiB2 composites. From, the permanent mould Al-TiB2 composite has an advantage of increase the properties over sand mould Al-TiB2 composite.


2013 ◽  
Vol 212 ◽  
pp. 59-62 ◽  
Author(s):  
Jerzy Myalski ◽  
Jakub Wieczorek ◽  
Adam Płachta

The change of matrix and usage of the aluminum alloys designed for the metal forming in making the composite suspension allows to extend the processing possibility of this type of materials. The possibility of the metal forming of the composites obtained by mechanical mixing will extend the range of composite materials usage. Applying of the metal forming e.g. matrix forging, embossing, pressing or rolling, will allow to remove the incoherence of the structure created while casting and removing casting failures. In order to avoid the appearance of the casting failures the homogenization conditions need to be changed. Inserting the particles into the matrix influences on the shortening of the composite solidification. The type of the applied particles influenced the sedimentation process and reinforcement agglomeration in the structure of the composite. Opposite to the composites reinforced with one-phase particles applying the fasess mixture (glassy carbon and silicon carbide) triggered significant limitation in the segregation process while casting solidification. Inserting the particles into the AW-AlCu2SiMn matrix lowers the mechanical properties tension and impact value strength. The most beneficial mechanical properties were gained in case of heterofasess composites reinforced with the particle mixture of SiC and glass carbon. The chemical composition of the matrix material (AW-AlCu2SiMn) allows to increase additionally mechanical characteristics by the precipitation hardening reached through heat casting forming.


2021 ◽  
pp. 36-45
Author(s):  
E.I. Krasnov ◽  
◽  
V.M. Serpova ◽  
L.G. Khodykin ◽  
A.V. Gololobov ◽  
...  

Presents a literature review in the field of methods for strengthening titanium and its alloys by introducing various refractory particles into the matrix. The main problematic issues related to the chemical nature of refractory particles and titanium alloys that arise during hardening are briefly described. The main structural, physical and mechanical properties and morphology of such metal composite materials are described. The dependence of the influence of various refractory particles and their amount, as well as the effect of heat treatment on the physical and mechanical properties of microns based on titanium alloys, is presented.


2018 ◽  
Vol 875 ◽  
pp. 183-186 ◽  
Author(s):  
I.V. Stefanenko ◽  
Valery N. Azarov ◽  
Katerina A. Trokhimchuk ◽  
Marina V. Trokhimchuk

The paper shows that the fulfillment of construction works influences the level of fine dust content in urban environment. Investigations of fine dust emissions in the zones of earth excavations and soil spoil banks caused by construction works were carried out. The authors conducted an integrated investigation of the physico-chemical processes in the surface layer of the atmosphere in the course of construction works, which was based on the field and computational experiments. With the help of a laboratory wind-tunnel plant, it was revealed that the character of dust emission during the development of dispersive massifs depends on the climatic conditions, in particular on the wind velocity and the physical-and-mechanical properties of the rocks (humidity, porosity, plasticity indices). A specific-purpose GIS application has been designed which allows modelling the dynamics of air flows in the territories with anthropogenic development. The application is based on the methods of mathematical and simulation modelling, the methods of visualization and surface plotting as well as the methods of software applications development.


Author(s):  
Atoyebi Olumoyewa Dotun ◽  
Adeolu Adesoji Adediran ◽  
Adisa Cephas Oluwatimilehin

The current work reports on the fabrication of composite matrix from saw dust (SD) and recycled polyethylene terephthalate (PET) at different weight ratio by flat-pressed method. Wood plastic composites (WPCs) were made with a thickness of 15 mm after mixing the saw dust and PET followed by a three phase press cycle. Physical properties (Density, Water Absorption (WA) and Thickness Swelling (TS)) and Mechanical properties (Modulus of Elasticity (MOE) and Modulus of Rupture (MOR)) were determined base on the mixing ratios according to the standard. WA and TS were measured after 2 h and 24 h of immersion in water. The results showed that as the density increased, the SD content decreased from 90 % to 50 % into the matrix. However, WA and TS decreases when the PET content increased in the matrix. Remarkably, the MOE and MOR attained a maximum point at 964.199 N/mm2and 9.03 N/mm2respectively in 50 % SD content. In comparism with standard, boards D and E can be classified as medium density boards while A, B and C are low density boards. The results indicated that the fabrication of WPCs from sawdust and PET would technically be feasible for indoor uses in building due to favorable physical properties exhibited. The mechanical properties response showed that it cannot be used for structural or load bearing application.


2012 ◽  
Vol 184-185 ◽  
pp. 1255-1258
Author(s):  
Zhuang Li ◽  
Di Wu ◽  
Wei Lv

The important factors that affect the formability of the cold forging steel are its surface quality and internal defects. The cracking phenomenon was taken place during cold forging of ML25Mn steel. In this study, microstructural analyses were made on around the cracked regions of the steel. The reason of cracking, which occurred during cold forging for ML25Mn steel, was investigated based on SEM observation in detail. The results have shown that the crack forming during cold forging process is not related to the chemical composition for ML25Mn steel. Cracking is not resulted from high hardness of the steel rods. There are some non-metallic inclusions in the matrix of ML25Mn steel, and the film-like inclusions are composed of MnS, CaS and complex oxides containing Mg, Al, Mn, Fe, S, Ca and O. The formation of non-metallic inclusions is the result of the deoxidation and the solidification during smelting and casting of steel.


Author(s):  
M. A. Salem ◽  
I. G. El-Batanony ◽  
M. Ghanem ◽  
Mohamed Ibrahim Abd ElAal

Different Al-SiC metal matrix composites (MMCs) with a different matrix, reinforcement sizes, and volume fractions were fabricated using ball milling (BM) and powder metallurgy (PM) techniques. Al and Al-SiC composites with different volume fractions were milled for 120 h. Then, the Al and Al-SiC composites were pressed under 125 MPa and finally sintered at 450 °C. Moreover, microsize and combination between micro and nano sizes Al-SiC samples were prepared by the same way. The effect of the Al matrix, SiC reinforcement sizes and the SiC volume fraction on the microstructure evolution, physical and mechanical properties of the produced composites was investigated. The BM and powder metallurgy techniques followed by sintering produce fully dense Al-SiC composite samples with different matrix and reinforcement sizes. The SiC particle size was observed to have a higher effect on the thermal conductivity, electrical resistivity, and microhardness of the produced composites than that of the SiC volume fraction. The decreasing of the Al and SiC particle sizes and increasing of the SiC volume fraction deteriorate the physical properties. On the other hand, the microhardness was enhanced with the decreasing of the Al, SiC particle sizes and the increasing of the SiC volume fraction.


2012 ◽  
Vol 727-728 ◽  
pp. 609-613
Author(s):  
P.C.F. Menezes ◽  
Taciana Regina de Gouveia Silva ◽  
Ana Cristina Figueiredo de Melo Costa ◽  
Edcleide Maria Araújo

The research in composites attempt to predict the physico-chemical and mechanical a given mixture of materials. In this work, a composite was produced using as the polyamide 6 matrix and how the burden of nickel ferrite was incorporated as powders calcined at 1200°C and concentration of 50 wt.%. This mixture was compacted in a hydraulic press with heating and characterized by XRD, SEM and TG. XRD results showed the characteristic peaks of polyamide 6 and ferrite. SEM results showed a good dispersion of nickel ferrite loading in the matrix, the presence of larger clusters and evenly distributed load for the composite calcined at 1200 ° C. TG curves showed that the addition of loading of calcined nickel ferrite promoted an increase in thermal stability of the composite compared to pure polyamide.


e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Shadi Houshyar ◽  
Robert A. Shanks

AbstractPreparation and characterization of novel composites, consisting of polypropylene (PP) fibres in a random poly(propylene-co-ethylene) (PPE) matrix, were investigated. These composites possess unique properties, due to chemical compatibility of the two polymers allowing creation of strong physico-chemical interactions and strong interfacial bonds. The difference between the melting temperatures of PP fibre and PPE was exploited in order to establish processing conditions for the composites. Suitable conditions were chosen so that the matrix was a liquid, to ensure good wetting and impregnation of the fibres, though the temperature must not be high enough to melt the fibres. The morphology of the composites was investigated using optical and scanning electron microscopy. Optical microscope images showed that transcrystallization of the matrix was observed on PP fibre surfaces. SEM photographs displayed a thin layer of matrix on the reinforcement, attributed to good impregnation and wetting of the fibres. Adhesion between PPE matrix and PP fibres was characterized using a microbond test inspired by a fibre pull-out technique. The results showed that adhesion was appreciably increased when PP fibres were used instead of glass fibres in the matrix. Nevertheless, thermal processing conditions of the composites caused reduction in mechanical behaviour of the reinforcement.


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