بررسي و امكان سنجي استفاده از فويلهاي توليد شده به روش الكتروفرمينگ در فرآيند ساخت به كمك آلتراسونيك

چكيده انگليسي :

91 Feasibility Study of Using Electroformed Thin Nickel Foils in Ultrasonic Consolidation Process Vahid Mohammadi v mohammadi@me iut ac ir Date of Submission 2013 01 20 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisors Alireza Fadaie Tehrani mcjaft@cc iut ac ir Mohsen Badrossamay mohsen badrossamay@cc iut ac ir Abstract Ultrasonic Consolidation is a solid state additive manufacturing process In this process thin metal foils are welded together by using high frequency vibration energy under pressure to create a metallurgical bond without melting the base material In Ultrasonic Consolidation bonding would be created in a temperature below 50 of metals nickel s melting point On the other hand Electroforming is an electrodeposition process similar to electroplating Electroforming is the production or reproduction of specimens by electrodeposition upon a mandrel or mould that is subsequently separated from the deposit It s noticeable that Electroforming is economically suitable for foil production Furthermore the capability of Electroforming to produce foils with fine surfaces are not negligible and surface roughness can change friction coefficient Moreover it is commonly believed that in Ultrasonic Consolidation process friction at the mating surfaces plays an important role in the bonding process by removing surface contaminants and producing adequate plastic strain to bond two adjacent foils to each other Therefore in this investigation founding a novel hybrid manufacturing process based on these two processes was studied So it was examined if electroformed nickel foils could be bonded by Ultrasonic Consolidation First nickel foil samples with 100 150 micrometer thickness were produced by Electroforming Sulphamate solution with 2 7A dm2 current density was used to obtain the best achievable roughness on foil Afterward a number of mechanical properties of fabricated foils including friction coefficient were measured A custom fabricated tribometer was designed and made to measure friction coefficient values in ambient and elevated temperature Results show that friction coefficient increases by temperature elevation up to 150OC and after that it decreases up to almost 200OC then within temperature elevation friction coefficient value doesn t change up to 370OC Finally a set of experimental tests were conducted by applying a 10 micrometer amplitude and 20 kHz frequency vibration to predict the effect of applied vibration in foils interface The results of Ultrasonic Consolidation tests support creation of bonding between electroformed foils by applying a 700W ultrasonic vibration after 0 1 second but this bonding wasn t continues because the used tool could not roll during applying vibration Consequently welded region was line shape Therefore after cutting the bounded interface bounded region couldn t be seen by an optical microscope So it was concluded that the bonding was not due to merger of two adjacent foils atoms and it s maybe created by mechanical interlocking The other hypothesis is that during cutting the interface the bonded area was damaged and couldn t be seen later by a microscope Since the strength of bonding was significant and mechanical interlocking couldn t make such a strong bonding the later hypothesis is more probable Additionally it should be noticed that it was proved that by using foils with rougher surfaces due to decrease of friction coefficient no bonding was occurred Keywords PDF created with pdfFactory trial version www pdffactory com

محمدي، وحيد

بررسي و امكان سنجي استفاده از فويلهاي توليد شده به روش الكتروفرمينگ در فرآيند ساخت به كمك آلتراسونيك

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