پديد آورنده :
انوري، راضيه
عنوان :
بهبود خواص مكانيكي و رفتار تريبولوژيكي آلياژ AL6061 توسط نانو كامپوزيت هيبريدي توسعه يافته با استفاده از فرايند اصطكاكي اغتشاشي
مقطع تحصيلي :
كارشناسي ارشد
گرايش تحصيلي :
شناسايي و انتخاب و روش ساخت مواد
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك
صفحه شمار :
پانزده، 112ص.: مصور، جدول، نمودار
استاد راهنما :
فتح الله كريم زاده، محمدحسين عنايتي
توصيفگر ها :
نانو كامپوزيت زمينه آلومينيومي , تركيبات بين فلزي AL-Cr , رفتار سايشي , خواص مكانيكي
تاريخ نمايه سازي :
1394/05/12
استاد داور :
محمدعلي گلعذار، حميدرضا سليمي
تاريخ ورود اطلاعات :
1396/10/03
چكيده فارسي :
به فارسي و انگليسي
چكيده انگليسي :
Improvement of Mechanical and Wear Behaviour of Al6061 with Hybrid Nanocomposite Fabricated by Friction stir Processing Sayede Razieh Anvari Email address sr anvari@ma iut ac ir Date of Submission Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor s Name Fathollah Karimzadeh Associate Professor karimzadeh f@cc iut ac ir Mohammad Hossein Enayati Associate Professor ena78@cc iut ac irAbstractRecently friction stir processing FSP was developed as a generic tool for microstructural modificationbased on the basic principles of FSW In this case a rotating tool is inserted in a workpiece for localizedmicrostructural modification for specific property enhancement In this research FSP was used to develop in situ Al Cr O hybrid nanocomposite on the surface of Al6061 plate A new procedure was introduced forapplying the reinforcement particles in which Cr2O3 powder was applied on Al6061 plate by atmosphereplasma spray and then the FSP was performed on the plate In order to optimize the FSP parameters microstructural and mechanical evaluations were performed The optimized parameters including toolrotational speed and tool travelling speed v were determined to be 630 rpm and 100 mm minrespectively In order to evaluation the effects of the friction stir processing on mechanical and tribologicalbehavior tensile hardness and wear tests were performed on base metal FS processed and nanocompositesamples Dominating wear mechanisms were investigated by surface examination of and studying of wearproducts using scanning electron microscopy SEM Microstructur of nanocomposite was investigated byscanning electron microscopy and transmission electron microscopy TEM Phase analysis was perfomedwith X ray diffraction XRD and energy dispersive spectrometer EDS Ratio of slope method was used forquantitative analysis and that amounts of different phases were determined Microstructural evaluation hasshown fine grain structure in stir zone which is decreased from 78 m for base metal to 6 m Results haveindicated that when the ratio of v is less than 5 rpm mm min 1 due to insufficient heat input microscopic voids were produced in stir zone During first three passes of FSP due to thermomechanicalcondition Cr2O3 was reduced with Al so pure Cr and Al2O3 were produced With increasing the number ofFSP passes intermetallic compounds including Al13Cr2 and Al11Cr2 were appeared as a result of reactionbetween Al and Cr With respect to the results reaction mechanism in FSP was suggested According to thismechanism during the FSP Cr were surrounded by continuous Al matrix Al are easily deformed andwrapped around the Cr to construct the composite particles The reaction between Al and Cr is exothermic inwhich a Al13Cr2 and Al11Cr2 phases grow at the Cr Al interface as a spherical shell The heat provided byfriction stir of the rotating tool can initiate the exothermic reaction At low temperature Al is the fastestdiffusing species in the Cr Al diffusion couples Therefore Al13Cr2 and Al11Cr2 grows via the diffusion of Alto the Cr phase at Al Cr interface TEM analysis showed that nanosize reinforcements distribute uniformly inaluminum matrix After six pass FSP Al13Cr2 Al11Cr2 and Al2O3 were determined 4 95 4 58 and 8 67respectively Maximum hardness of base metal friction stir processed sample without reinforcements andsurface nanocomposite were measured to be 97 68 and 147HV respectively Also ultimate tensile strengthincreased from 324 Mpa for pure Al to 518 Mpa for nanocomposite Elongation was decreased from 13 forAl6061 to 6 5 for nanocomposite after six pass FSP but fracture suface of nanocomposite showed ductilefracture Wear test results showed improved wear resistance in nanocomposite samples Wear rates of basemetal FS processed and nanocomposite were 0 0255 0 037 and 0 0055 mgr m respectively Wear rates forFSprocessed samples were less than base metal It is due to solution of some precipitati
استاد راهنما :
فتح الله كريم زاده، محمدحسين عنايتي
استاد داور :
محمدعلي گلعذار، حميدرضا سليمي
