Properties of Metal Matrix Composite of Aluminium 11.8% Silicon Reinforced with Different Particulates

A composite material is a materials system composed of a mixture or combination of two or more micro or macro constituents that differ in form and chemical composition and which are essentially insoluble in each other. Metal matrix composites are engineered materials composed of an elemental or alloy matrix in which an insoluble second phasel reinforcer is embedded and distributed to achieve some property improvement. Particulate reinforced metal matrix composites constitute a major portion of these advanced materials. Aluminium-silicon alloys, as a matrix material, are characterized by lightweight, good strength-to-weight ratio, ease of fabrication at reasonable cost, high strength at elevated temperature, good thermal conductivity, excellent castability, good weldability, excellent corrosion resistance and wear resistance properties. Application of particulate reinforced composites in the aerospace, automotive, transportation and construction industries depends on the choice of cost affordable factor. In this research work, particulate reinforced metal matrix composites are processed by vortex method, a melt stirring liquid metallurgy technique. Four different particulates namely, graphite, combination of tungsten carbide and aluminium silicate for hybrid composite reinforcement, quartz and titanium carbide are used as second phase reinforcers for reinforcement in the matrix. Aluminium-1 1.8% silicon alloy is selected as the matrix material and the particulates are mixed in different weight fraction %. Slab composite castings are made by pouring the composite mixture in grey cast, steel and copper permanent-molds. Process parameters like pouring temperature, particulate preheating temperature, impeller blade speed and shape are optimized and composite castings containing different weight fraction % of particulate are made by permanent-mold casting process. Effects on different weight fraction % addition of particulate on the particulate distribution in aluminum-1 1.8% silicon alloy composites are studied. The processed particulate reinforced composites are subjected to mechanical tensile testing and the properties are determined for different type of particulate reinforcements in the aluminium-11.8% silicon alloy matrix. Besides, hardness, density, impact strength-charpy, fracture toughness, electrical resistivity, electrical conductivity, thermal diffusivity, thermal conductivity, thermal expansion coefficient measurements are performed by using the appropriate equipments and machines. Metallographic studies of the processed particulate composites are conducted by optical microscopy and photomicrographs are captured at different magnifications to reveal and examine the particulate distribution in the aluminium-1 1.8% silicon alloy matrix. SEM observation of the fracture surfaces of tensile tested, charpy impact tested specimens are performed to study the fracture mechanics and surface characteristics with the aid of captured SEM fractographs. Interfacial bonding features of the processed composites are also analyzed with the help of SEM. Besides, slab castings without particulate addition are made and compared with the results based on the properties and microstructural features, particularly for the uniformity of particulate distribution in the aluminum-1 1.8% silicon alloy base matrix. It is found that the properties of the processed particulate reinforced aluminium-1 1.8% silicon alloy matrix composites are superior to the cast monolithic aluminium-1 1.8% silicon alloy based on the above-mentioned properties studies. Photomicrographs of the processed composites based on the metallographic studies have confirmed the uniformity of particulate distribution in the aluminium- 1 1.8% silicon alloy matrix

Foundry Metallurgy of Tungsten Carbide and Aluminium Silicate Particulate Reinforced LM6 Alloy Hybrid Composites

Hybrid composites are advanced composite materials in which a combination of two or more second phase particulates or fibers are reinforced in a base matrix. In this research paper, liquid metallurgical processing of a new hybrid composite material containing tungsten carbide particulate and aluminium silicate particulate combined at different weight fraction percentage is discussed. Manufacturing of such combined tungsten carbide particulate and aluminium silicate particulate reinforced aluminium-11.8% silicon alloy matrix composites by metal casting technology has some advantages of processing the composites by near net shape techniques. Turbulence generated by the liquid metallurgical vortex mixing technique is the easiest technique for processing these hybrid composites.  Aluminium-11.8% silicon alloy hybrid particulate, combined tungsten carbide and aluminium silicate reinforced composites is related to their higher strength, lightweight, hardness, higher temperature resistance and wear resistance than that of any conventional monolithic materials. In this experimental work, aluminum-silicon alloy composites containing tungsten carbide and aluminium silicate combined particulate combination of 2.5%, 5.0%, 7.5% and 10.0% on weight fraction basis are produced by using the liquid stirring method. The size of the tungsten carbide particulateis 47.30 micron supplied by Aldrich, USA and the size of the aluminiumsilicate particulate is equal to 157.10 micron supplied by Fluka, USA.This paper discusses the vortex stirring process to produce these hybridcomposite castings. These are processed in the form of slab containing2.5%, 5%, 7.5% and 10% weight fraction of the two combination ofparticulate equally reinforced in LM6 alloy. A grey cast iron metallic moldis used to pour the hybrid composite slurry mixture. Mechanical, electricaland thermal properties are determined and all these aspects are discussedin this paper. The microstructures of the processed hybrid composites arestudied at different magnifications and photomicrographs are captured toidentify the presence of the two different reinforced particulates and itsdistribution uniformity. Fracture surface analysis has been performed tostudy the failure mechanisms

Beneficial roles of nutrients as immunostimulants in aquaculture: A review

Protein deficiency is a major difficulty for human needs in the past few decades, while different types of aquatic species are rich in high quality protein. Therefore, aquaculture is considered as the main developing food production sector globally. Bacterial infections are the main problem for aquaculture, and their outbreaks have a great impact on productivity, and previously indiscriminate use of antibiotics to control them. However, the emergence of multidrug-resistant pathogens might lead to sudden infectious disease outbreaks resulting in serious economic loss. Immunostimulants application is an effective technique to protect and enhance the immune system of aquatic animals and therefore improve aquaculture production. Nutrient immunostimulants such as essential fatty acids, amino acids, vitamins, and minerals are the most important responsibility to improve aquaculture production, as well as the cost of this method, which is effective, non-toxic, and environment friendly. These nutrient immunostimulants are supportive to increase the immune system, antioxidant, antiinflammatory, and infection resistance of aquatic animals. In addition, nutritional feed additives improved feed palatability and the excellence of aquatic products and also enhance gut functions. Some information is available on nutrient immunostimulants in aquaculture applications, and this review provides information on different kinds of nutritional administration used in aquaculture to enhance positive impacts on aquatic animals’ health as well as feed quality development. This review will provide theoretical references for the application of nutrient immunostimulants in aquatic feeds

Computers in Foundries

Computers have now entered into the foundryengineering. Foundry mechanization and modernizationare of considerable importance today when the foundryhas evolved from an ancient art into a modern scienceand it is fully controlled and monitored by computers.Modernization is the only key to improve casting qualityand productivity. From industrial point of view, theyhave been in use in the administrative areas of finance,accounting, personnel records, wage, salaries, andinventory control for a long period. Many foundry machinesystems are computerized. Due to the entry of computersin foundries, fatigue and strain on the workers and staffshave been considerably reduced during working andwork culture has improved tremendously. Improved workculture can lead to a sense of participation, involvement,and creativity. This review paper discusses on the role,prospects, and application of computers in foundries.Besides, an introduction on the computer aided foundrymodel design and computer aided foundry die design arepresented precisely in this paper. It also discusses on thenumerical simulation of casting solidification performed infoundries and a brief information about the computerizedand automated foundry line have been provided in thistechnical paper. The applications of expert systems infoundries and various types of foundry software packagescommonly used in the metal casting industries areexplained in detail in this review paper

Green compression strength of tin mine tailing sand for green sand casting mould

Tailing sand is the residue mineral from tin extraction that contains between 94% and 99.5% silica, which can be used as moulding sand. It is found in abundance in the Kinta Valley in the state of Perak, Malaysia. Adequate water content and clay in moulding sand are important factors for better strength and casting quality of products made from tailing sand. Samples of tailing sand were investigated according to the American Foundrymen Society (AFS) standard. Cylindrical test pieces of Ø50 mm×50 mm in height from various sand-water ratios were compacted by applying three ramming blows of 6666g each using a Ridsdale-Dietert metric standard rammer. The specimens were tested for green compression strength using a Ridsdale-Dietert universal sand strength machine. Before the tests were conducted, moisture content of the tailing sand was measured using a moisture analyser. A mixture bonded with 8% clay possesses higher green compression strength compared to samples bonded with 4% clay. The results also show that in order to achieve maximum green compression strength, the optimum allowable moisture content for mixtures bonded with 8% clay is ranged between 3.75 and 6.5% and for mixtures bonded with 4% clay is 3-5.5%

Processing and characterisation of particulate reinforced aluminium silicon matrix composite

Purpose: This paper describes and discusses the processing and characterization of quartz particulate reinforced aluminium-silicon alloy matrix composite. Design/methodology/approach: In this regard, quartz-silicon dioxide particulate reinforced LM6 alloy matrix composites were fabricated by carbon dioxide sand molding process with different particulate volume fraction. Tensile tests and scanning electron microscopic studies were conducted to determine the maximum load, tensile strength, modulus of elasticity and fracture surface analysis have been performed to characterize the morphological aspects of the test samples after tensile testing. Findings: Hardness values are measured for the quartz particulate reinforced LM6 alloy composites and it has been found that it gradually increases with increased addition of the reinforcement phase. The tensile strength of the composites decreases with the increase in addition of quartz particulate. Research limitations/implications: The results allows to determine the structure and properties of the aluminium silicon matrix composite materials. Originality/value: In addition, this research article is well featured by the particulate-matrix bonding and interface studies which have been conducted to understand the processed composite materials mechanical behavior and it was well supported by the fractographs taken using the scanning electron microscope (SEM)

The effect of bentonite clay on green compression strength for tailing sands from old tin mines in Perak state, Malaysia for making green sand casting mould

Clay has an important role in making green sand casting mould beside water. Clay acts as binders, holding the sand grains together. Water is needed to activate the clay bond. Without the addition of water on clay, no strength would be achieved on sand mould, as the sand and clay would be just two dry materials. Bentonite clay was used in this study. Adequate clay content with suitable moisture in moulding sand is important for optimum strength and casting quality. Too little or too much clay will not give proper strength. Green compression strength is one of the mechanical properties to be considered for making green sand casting mould. The green compression strength of foundry sand is the maximum compressive strength that a mixture is capable of sustaining when prepared, rammed and tested according to standard procedure. For this study, test is conducted according to Foundry Sand Testing Equipment Operating Instructions from Ridsdale and Dietert. Result from this study indicates that tailing sand has potential for making green sand casting mould in term of green compression strength. Other factors that must be considered are permeability and shatter index

Biochemical and biophysical analyses of tight junction permeability made of claudin-16 and claudin-19 dimerization

The molecular nature of tight junction architecture and permeability is a long-standing mystery. Here, by comprehensive biochemical, biophysical, genetic, and electron microscopic analyses of claudin-16 and -19 interactions—two claudins that play key polygenic roles in fatal human renal disease, FHHNC—we found that 1) claudin-16 and -19 form a stable dimer through cis association of transmembrane domains 3 and 4; 2) mutations disrupting the claudin-16 and -19 cis interaction increase tight junction ultrastructural complexity but reduce tight junction permeability; and 3) no claudin hemichannel or heterotypic channel made of claudin-16 and -19 trans interaction can exist. These principles can be used to artificially alter tight junction permeabilities in various epithelia by manipulating selective claudin interactions. Our study also emphasizes the use of a novel recording approach based on scanning ion conductance microscopy to resolve tight junction permeabilities with submicrometer precision

Effect of moisture content on the permeability of tailing sand samples gathered from ex tin mines in Perak state Malaysia

Tailing sand is one of the residue minerals obtained after tin extraction. It contains silica in between 94% and 99.5% and available in abundance at the Kinta Valley, Perak State, Malaysia. Permeability is one of the important molding sand properties and considered much in the sand casting mold preparation. This molding sand property plays a vital role in the sand casting process and helps to remove the gases during the casting processing. In this research work, samples of tailing sands were gathered from four identified ex tin mines located at the Perak State, Malaysia. They were investigated by the standard sand testing procedures prescribed by the American Foundrymen Society (AFS). Sand specimens of size Ø50 mm×50 mm in height from various sand–water ratios bonded with 4% and 8% clay were compacted on applying three ramming blows of 6666 g each by using a Ridsdale-Dietert metric standard rammer. The specimens were tested for permeability number with the aid of a Ridsdale-Dietert permeability meter. Before the tests were conducted, the moisture content was measured by using a moisture analyzer. The results were compared with the properties of the molding sand samples collected from RCS Manufacturing Sdn. Bhd., the company supplying sand to the Proton Casting unit car manufacturing company. The molding sand sample sample bonded with 8% clay was found to have maximum permeability with an optimum allowable moisture content range of 3.5-6.0% and for the sand mixture bonded with 4% clay at 3.0-3.5% moisture