Materials Science Forum Vol. 1039

Abstract: The electrochemical discharge machining (ECDM) is a combination effect of electrochemical machining in which metal is removed through the electrochemical process and electrical discharge machining in which metal is removed by rapid current discharges between two electrodes which are separated by a dielectric liquid and subject to an electric voltage. Difficulty of machining nickel titanium alloys by conventional methods such as; the significant tool wear, the need of highly experienced operators, and an excessive degradation in the material performance due to the high thermal and mechanical effects of these methods. For these, reasons non-conventional methods such as electrical discharge machining and electro chemical machining are often used to fabricate NiTi alloys with better machining results. The experiments were conducted with various conditions of voltage (50,60,70 and 80)V, dielectric solution concentration (30 and 40% of NaOH) and nanoparticles silver, and copper content (0.5% Cu, 0.5% Ag, 0.5% Cu and Ag) in the (55% Ni-45%Ti) alloy samples. The machining experiments were designed according to Taguchi's design of experiments (L32). Grey relational analysis was used to optimize the responses of the ECDM process. Material removal rate (MRR), tool wear rate (TWR), and surface roughness (Ra) represent the response parameters for machining of the alloy samples prepared by the powder metallurgy route. To achieve the objectives of this research work MiniTab17 software was employed. The optimal conditions were: voltage of 50V, solution concentration of 40% and the sample (NiTi+0.5%Cu+0.5%Ag) have the highest effect on machining characteristics with MRR value of 0.04991mg/sec., tool wear rate value of 0.00125mg/sec., and surface roughness of 0.0117μm.

Abstract: The influence of applying an external distributed pressure along the upper surface of the molten metal (Aluminum ) during the solidification process on the temperature reduction profile was studied including the time of solidification of the cast and the phase change moving boundary location for two mould wall thicknesses (10mm and 15mm). A 3D model was built up by Solidworks and simulated by ANSYS FLUENT; each mould wall thickness was discussed for two press cases (1bar and 3bar) sequentially, comparing with no press cases. The discussion includes the ambient temperature effect, which is taken (300K then 310K), the overall cases that studied was 7 cases. The study shows a remarkable effect of press on the temperature reduction profile especially when mix with the mould thickness effect as well as the ambient temperature which has a great order in guiding the results. The results showed that the heat reduction increases by increasing the mould thickness as well as the applied pressure. Moreover, this effect will reduce the solidification time and the moving of the boundary of phase change become faster in appearance.

Abstract: The main objects of this paper are to deal with the new technology of metal sheet forming using the incremental single-point tool to form the sheet metal. However, due to the needed long time to form the metal in incremental so that we used punching and then incremental forming to geometry the final shape of the product. By measuring the thickness and longitudinal strain and evaluating the hoop strain, it was noticed that the less depth in punching with less step size in incremental forming have a better strain effect in metal sheet forming. Keywords: Single point, incremental forming, Strain analysis, step size.

Abstract: The resistance spot welding is adopted to joint dissimilar alloys such as aluminum alloy 1100 , and low carbon steel alloy 1008 by using cover plate. This study aims to optimization the best conditions of dissimilar welding of Aluminum with low carbon steel by RSW, and improving the properties of joints by many method. three different variables were used for the welding process: welding current (5, 6 ,7 and 8 KA), weld time (0.5, 1 and 1.5 sec) and electrode force (13.2 and 15.5 N).The welding joints are ―examined by a scanning electron microscope SEM and a X-ray diffraction‖ for the purpose of discussing the causes of the improved characteristics. The results revealed that the best welding conditions were under welding current 7 KA , weld time 1 sec and electrode force 13.2 KN, where the joint possessed the maximum shear force (4.8KN) and after improvement the tensile shear force become (6.02 KN), in addition to presence of the intermetallic compounds at optimum condition , such as AlFe3,Al5Fe4 and Al13Fe4, in the joint layer between dissimilar metal improves of the tensile shear forces and hardness in fusion zone.

Abstract: A metal extrusion was process that extrusion puncture perforate surface of material to throw and flow across outlet of die. This operation was a complex process in extrusion while penetration occurred at same time. This process can be seen in many production operations, like in forming of making portion of metal strip, and forming of extruded portion in a complex fineblanking with extrusion operation. Also exhibit the operation properties and give the method of numerical solution. So increasing load to 610KN with increased friction factor to 0.7 and increased with increasing the reduction ratio and stroke of operation. For the results and mesh distortion, with allocations of strains may be predicted. Analyzing results was submitted of metal extruded may be classified into two zones for the different lineaments deformation. moreover, energy in the zones of deformation may be classified into two parts for their different lineaments of internal zone and contact zone with the die . Fracture location has been found from simulations. Keyword Load, Extrusion, upper bound, numerical solution

Abstract: Crude oil is one of the most important sources of energy in the world. To extract its multiple components, we need oil refineries. Refineries consist of multiple parts, including heat exchangers, furnaces, and others. It is known that one of the initial operations in the refineries is the process of gradually raising the temperature of crude oil to 370 degrees centigrade or higher. Hence, in this investigation the focus is on the furnaces and the corrosion in their tubes. The investigation was accomplished by reading the thickness of the tubes for the period from 2008 to 2020 with a test in every two year, had passed from their introduction into the work. Where the thickness of more than one point was measured on each tube in the same row and the corrosion rate was extracted for three furnaces, starting from the area of ​​heat transfer by radiation to the heat transfer area of ​​the convection in three different operating units. It was found that the highest percentage corrosion value between the standard tube thickness and the thickness of conduction position was 37% with the conduction zone, and 31% with radiation zone. There, the tubes specification was tested. Five percent Cr-0.5 Moly and the temperature of radiation zone was 578 °C to 613 °C and the stack temperature was 410 °C to 450 °C. So, the results show that the maximum erosion occur at the convection zone.

Abstract: The present paper concerns with studying the high complexity nature of the EDM multiple discharge analysis transformed into a feasible solvable mathematical model for the die steel workpiece type AISI D2, the copper and graphite materials electrodes, and the kerosene dielectric by setting the Transient Thermal and the Multiphysics analyses domain loads models using the ANSYS 15.0 finite element analysis. Two load steps modeled the entering setting time analysis, six sub-periods setting time cycle, four heating, and two cooling periods, six transient temperature values, and four transient thermal convection models. The radius spark (discharge channel), the total number of discharges sparks, the total heat power generation, the absorbed heat flux fractions by the electrodes, the workpieces and kerosene fluid dielectric, the heat-affected zones (HAZ), the hard white recast layer thickness (WLT) and properties, the workpiece fatigue safety factor and life after EDM machining were determined and simulated. The thermal model errors compared with theoretical calculations and a modeled predicted equation were also deduced and verified. The experimental results evinced that the maximum total heat flux generated using the graphite material electrodes is (2.619E+009 W/m2) which is higher than when using copper material electrodes by (82.4%), while the minimum value of the white layer thickness (WLT) after EDM machining using graphite tool electrodes is (8.34 μm), which it gives an improvement comparing with using of copper tool electrodes by (40.0%). The macrographic and microstructure evaluation manifest that the discharge spark craters sizes when using graphite tool electrodes reached their sizes. The maximum fatigue stresses and fatigue safety factor when using copper tool electrodes are (240 MPa) and (0.89) which is higher by a value of (3.35%) and (3.45%) comparing with the using of graphite electrodes, respectively.

Abstract: This research is devoted to study the effect of addition (2%) TiO₂ with different weight percent of fly ash particulate (0, 2, 4, 6%) to 2024 Al alloy on the wear behavior and hardness. The alloy was fabricated by the liquid metallurgy method. The results founds that the wear rate decreased from 0.55 with 0% fly ash to 0.18 at addition percentage of 6% fly ash. Also, the results reveal increasing the samples wear rate with increasing the load and loaded time. The rate of wear was decreased with increasing the sliding speed. Also, the values of hardness increased from 120VH to 160VH with rising the fly ash from 0% to 6%. Keywords: Fly Ash addition, TiO₂, 2024 Al Alloy, Wear Resistance, Hardness.

Abstract: In this work, zinc oxide were synthesized by biological method using Aloe vera plant and the water solution of zinc . The detail characterization of the nanoparticles was carried out on different PH value . The samples were examined with an X-ray diffraction device and the results were almost identical to the JCPDS standard. It was also observed that the size of the particles was affected by the basic and acidic medium in a large way, as the results obtained from the Transmission Electron Microscopy The particle sizes ranged from 5nm to 100nm depending on the change of the PH value.

Abstract: Abstract. Laser ablation of a silver target immersed in distilled water utilizing Nd: YAG laser with wavelengths of 532nm,1064nm, and 1320nm was carried out to fabricate silver nanoparticles. The synthesis of Ag NPs was carried out using various laser energy (200-1000 mJ) and different pulses (200-1000 pulse). Optical properties for the Ag nanoparticles solution were tested using UV-Visible spectrum, while the morphological properties for the Ag-nanoparticles solution after deposited on glass were tested using the atomic force microscope (AFM). The results showed that the synthesis of the Ag-nanoparticles using pulsed laser ablation in liquid (PLAL) (water) gives nanoparticles with homogeneous grain distribution and uniform surface roughness. It was found that the absorption peaks of Ag NPs increase by increasing the number of pulses shoot for the same laser wavelength and laser energy, and the reported maximum value of absorption peak is 0.363 when using 1000 pulses shoot. AFM results showed that the average diameter of the Ag NPs prepared by PLAL increases with increasing the laser wavelength. However, when using laser wavelengths of 1320nm,1064nm, and 532nm, the resulted average diameter of silver nanoparticles will be 55.38nm, 34.18nm, and 30.3nm, respectively. Finally, the average surface roughness of the Ag NPs prepared by PLAL increased with increasing the laser wavelength. The obtained average surface roughness of silver nanoparticles when using wavelengths of 1320nm,1064nm, and 532nm were 2.75nm, 1.19nm, and1.06nm, respectively.