Influence of SiC Content on Microstructure, Dislocation Density and Mechanical Behavior of Cu/SiC Composite

The present investigation has examined the impact of micro-SiC on microstructure, dislocation and mechanical behavior of Cu/SiC composite. The micro-composite samples have been fabricated under a constant pressure (480 MPa) and sintered temperature (860oC) for 2 h. The sintering process was performed under argon gas. The microstructure examination was conducted using SEM/EDS and XRD diffraction. The SiC contents were 0, 5, 10,15,20,25 and 30 volume fraction. The outcomes showed that the density was significantly decreased with an increase of silicon carbide content. The relative densities of Cu and Cu/SiC composites was ranged from 91.24% to 83.56% for pure Cu and Cu/30 vol%SiC composites. The copper crystallite size was reduced with growing SiC content while the hardness, ultimate and yield compressive strength increased with increment of SiC volume fraction to 20% vol. The values of hardness, ultimate and yield compressive strength increased to 231 HV,343 and 176 N/mm2 , respectively for the composite sample containing 20% SiC particles with a percentage increase of 75%,26.6% and 57.2% compared with pure Cu.

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF STEELS FOR SHAPED CHARGE LINERS AND PRELIMINARY ASSESSMENT OF THE EFFECTIVENESS OF EXPERIMENTAL SHAPED CHARGES INTENDED FOR USE IN THE MINING INDUSTRY

The paper presents the results of investigation of the microstructure and mechanical properties of Fe-based materials designed for the manufacture of semi-spherical liners for experimental shaped charges. The tests were carried out on material samples taken from two semi-finished products, i.e. a rod for the manufacture of charge liners with a diameter of 50 mm using machining, and sheets for the manufacture of liners with a diameter of 100 mm using cold drawing. Microstructure examination was also carried out on a test specimen obtained using the additive method (3D-WAAM), made of low-carbon unalloyed steel wire. Firing tests on concrete blocks were carried out in order to quantify the effects of drilling at the Experimental Mine Barbara. The scope of the tests consisted of firing at cylindrical concrete blocks using projectiles containing 50 mm diameter liners made of Fe-based alloys. Based on the results of the laboratory material, two experimental steel grades were selected for further testing. Plates made of the selected steels will be used to manufacture charge liners with a diameter of 100 mm.

Grain characteristics, electrical conductivity, and hardness of Zn-doped Cu–3Si alloys system

The grain characteristics, electrical conductivity, hardness, and bulk density of Cu–3Si–(0.1—1 wt%)Zn alloys system fabricated by gravity casting technique were investigated experimentally using optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The study established the optimal alloy composition and the significance of zinc addition on the tested properties using response surface optimal design (RSOD). The cooled alloy samples underwent normalizing heat treatment at 900 °C for 0.5 h. The average grains size and grains distribution were analyzed using the linear intercept method (ImageJ). The microstructure examination revealed a change in grain characteristics (morphology and size) of the parent alloy by addition of 0.1 wt% zinc. The average grains size of the parent alloy decreased from 12 µm to 7.0 µm after 0.1 wt% zinc addition. This change in grain characteristics led to an increase in the hardness of the parent alloy by 42.2%, after adding 0.1 wt% zinc. The electrical conductivity of the parent alloy decreased from 46.3%IACS to 45.3%IACS, while the density was increased by 8.4% after adding 0.1 wt% zinc. The statistical data confirmed the significance of the change in properties. The result of optimization revealed Cu–3Si–0.233Zn as the optimal alloy composition with optimal properties. The Cu–3Si–xZn alloy demonstrated excellent properties suitable for the fabrication of electrical and automobile components.

Preparation and Characterization of Bioceramic Cordierite for Medical Applications

The study concentration on the fabricate of bioactive behavior of pure cordierite system and investigate the structure of phase transformation and physical characteristics. cordierite powders were synthesized by chemical coprecipitation, combined Cordierite gel with water-based sol–gel which begin fundamental from magnesium oxide MgO, Alumina Al2O3 and silicon oxide SiO2. Five specimens were prepared with different weight percentage of Mgo, Al2O3 and SiO2 powders. cylindrical shape samples were press by hydraulic press at 4 bar for 30 minutes. All specimens were sintered at 1250 0C.The microstructure examination of specimens was carried out using Field Emission Scanning Electron Microscope (FESEM), x-ray diffraction (XRD) and particle size analysis The analysis revealed cordierite phase formation at 1250 °C, and the intense peaks were identified for composites S4 and S5. The results also indicated the formation of spinel, cristobalite, corundum, protoestatite and cordierite for all the specimens.

Effect of Thermally Formed Alumina on Density of AlMgSi Alloys Extrudate Recycled Via Solid State Technique

Solid state recycling of aluminium via hot extrusion is a sustainable technique. The process performed before hot extrusion plays a vital role on the extrudate properties. In this study, the effect of naturally and thermally formed in-situ alumina on the extrudate density were investigated. Fours type of material identified as a solid as-received, non-treated recycle chip, 300 0C thermally treated recycle chip and 500 0C thermally treated recycle chip were prepared for the experiment. Prior to extrusion, the recycle chips were compacted into a chip-based billet, preheated and immediately extruded into a semi-finished product. The density test performed on the chip-based extrudate found that the type of chips influenced the density. The chip-based extrudate made of 300 0C and 500 0C thermally treated chips resulted in higher density than solid as-received and non-treated chips. Chip-based extrudate produced from 500 0C thermally treated chips resulted in density of 2724 kg/m3, which is the highest among the specimen. This density value was 0.7 % higher compared to the solid as-received extrudate. Microstructure examination on the cross-section revealed the alumina entrapped in the chip-based extrudate. The alumina entrapped in 500 0C thermally treated chips specimen was more prone than the non-treated and 300 0C thermally-treated chips. This finding explains the variation in the extrudate density.

Influence of Anisotropy Properties of as-Rolled CMn Plate on Welding Induced Distortion

Welding induced distortion remain persistent problems leading to the inferior on Product Quality. The study is to investigate on welding induced angular distortion due to effect of anisotropy properties of the As-rolled C-Mn plate. The outcome could enhance the minimum distortion while cutting the raw material on rolling direction for fabrication process. The Anisotropy properties of the base metal were analyzed with along and transverse to rolling direction through microstructure examination, hardness measurement and mechanical properties. Microstructure contains coarse grains of pearlite and ferrite in transverse to rolling, whereas fine grains along the rolling. Hardness was 80 and 84 HRB along and transverse to rolling respectively. A weld bead was laid on the plate’s substrate with along and transverse to the rolling and angular deflections were measured with a dial gauge indicator. Finite element analysis (FEA) was carried out to evaluate the angular deflection on both the rolling. From the experimental results, the anisotropy properties of the as-rolled plate had influenced on angular deflection and indicating with good agreement with FEA.

Microstructure Evaluation and Impurities in La Containing Silicon Oxynitrides

Oxynitride glasses are not yet commercialised primarily due to the impurities present in the network of these glasses. In this work, we investigated the microstructure and instinctive defects in nitrogen rich La-Si-O-N glasses. Glasses were prepared by heating a powder mixture of pure La metal, Si3N4, and SiO2 in a nitrogen atmosphere at 1650–1800 °C. The microstructure and impurities in the glasses were examined by optical microscopy, scanning electron microscopy, atomic force microscopy, and transmission electron microscopy in conjunction with electron energy-loss spectroscopy. Analyses showed that the glasses contain a small amount of spherical metal silicide particles, mostly amorphous or poorly crystalline, and having sizes typically ranging from 1 µm and less. The amount of silicide was estimated to be less than 2 vol. %. There was no systematic relation between silicide formation and glass composition or preparation temperature. The microstructure examination revealed that the opacity of these nitrogen rich glasses is due to the elemental Si arise from the decomposition reaction of silicon nitride and silicon oxide, at a high temperature above ~1600 °C and from the metallic silicide particles formed by the reduction of silicon oxide and silicon nitride at an early stage of reaction to form a silicide intermetallic with the La metal.

Genetic Algorithm-Based Optimization of Friction Stir Welding Process Parameters on Aa7108

This research paper deals with the characterization of friction stir welding aluminium 7108 with twin stir technology. The coupons of the above metal were friction stir welded using a cylindrical pin with counter-rotating twin stir technology using at constant speed 900, 1200, 1500,1800 with four different feed rates of 30,50,70,90 mm/min. Microstructure examination showed the variation of each zone and their influence on the mechanical properties. Also, tensile strength and hardness measurements were done as a part of the mechanical characterization and correlation between mechanical and metallurgical properties and deduced at the speed of 1500 rpm. Friction stir welding process parameters such as tool rotational speed (rpm), tool feed (mm/min) were considered to find their influence on the tensile strength (MPa) and hardness (HRB). A genetic algorithm (GA) was employed by taking the fitness function as a combined objective function to optimize the friction welding process parameters to predict the maximum value of the tensile strength and hardness. The confirmation test also revealed good closeness to the genetic algorithm predicted results and the optimized value of process parameters for different weights of the tensile and hardness have been predicted in the model.

Weldability of Grade 2 Titanium Sheets with Pulsed Nd:YAG Microlaser Welding Filler and Without Filler

Laser welding method is widely used in the welding of different materials. Deep penetration, low heat input, narrow heat affect zone, low stress-strain, and distortion are important features of this welding method as compared to other joint methods. Today, it is possible to see the applications of laser welding in the repair of precious metals, moulds, and machine parts. The laser welding method is preferred in the manufacture of many parts of precious metals. Titanium and particularly Grade 2 alloys are used in a wide range of applications, from medical applications to the aerospace industry applications. Since titanium is made of precious metals, it is of great use in manufacturing without much scrap. In the joints made by welding, it is estimated that the amount of scrap loss will decrease as a result of the potential to predict the distortion that the material will undergo and to provide more controlled planning of the current production. In this study, the weldability of 0.6 mm sheet materials with laser butt-welding was investigated. The effects of pulsed micro laser welding parameters on the microstructure, mechanical properties, and surface morphology of the fractures were investigated. As a result of the microstructure examination, it was found that cross-section narrowing was seen without filling welding. Fracture of the welded joints occurred in the base metal, showing an ultimate tensile strength of approximately 248 MPa with an elongation of 26.7 %.