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Titanium alloy Ti-6Al-4V is one of the most used industrial alloys that is used often in important and risky applications. One of the requirements for machining such parts is to achieve the appropriate surface integrity. Powder mixed electrical discharge machining is a process which has different mechanism compared with traditional electrical discharge machining process; and it often used in order to obtain good surface finish. In this study two different kind of Nano powders SiO2 and Al2O3 added in dielectric for machining of Ti-6Al-4V titanium alloy; so that the effect of adding them on the output characteristics of the electric discharge process, including removal rate, tool wear ratio, surface roughness and integrity is investigated and compared. In order to investigate surface micro cracks and heat altered layer, surface and cross section of it were studied by scanning electron microscopy imaging. The results show addition of Nano powders into dielectric, especially SiO2, increases material removal rate, the effect of Nano powders on tool wear ratio depends on machining condition and setting. SiO2 Nano powder decreases surface roughness more than Al2O3 Nano powder. Surface integrity of machined sample in terms of micro-cracks and depth of the heat altered layer is improved with the addition of nanoparticles.

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The aim of this study, design and fabrication a prototype of double-tube magnetorheological damper (MR damper) involving micron sized and soft ferro magnetic of carbonyl iron (CI) particles and stabilizer nanoparticles of silicone (SiO2). Whiles initially magnetorheological fluid as its application and required, designed and fabricated. Then sedimentation and magnetorheometry tests (in mode of shear) was done. That the resulting of sedimentation test, illustrated that after 10 days, the value of sedimentation just was 15% and maximum of shear stress in maximum current was about 20kpa, that was desired. Then the magnetic section of the research, was conducted using the existing relationships and Maxwell software, at the end, using this data, the geometric dimensions of the MR damper, designed and fabricated. appropriate damper, was double tube type damper and at the combination of two valve and shear modes. After fabrication of appropriate damper, damping test was carried out on appropriate damper by damping test machine, that with regard to the receive graphs from test, at currents of 0 ,1 and 2 amps and speed of 0.05m/s, the magnitude of damping force aspect zero current(conventional damper), at saturate magnetic intensity (H_mr) was 5 times conventional damper. That was desired.