پديد آورنده :
سجادي، مهناز
عنوان :
ساخت و مشخصه يابي آلياژهاي آنتروپي بالا نانوساختار( AlCoFeNiX(Cu,Zn به روش آلياژسازي مكانيكي و ارزيابي خواص مكانيكي آن
مقطع تحصيلي :
كارشناسي ارشد
گرايش تحصيلي :
شناسايي و انتخاب مواد
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد
صفحه شمار :
پانزده، ۱۱۷ص.: مصور، جدول، نمودار
استاد راهنما :
محمدرضا طرقي نژاد
استاد مشاور :
فتح الله كريم زاده
توصيفگر ها :
آلياژ آنتروپي بالا , آلياژسازي مكانيكي , نانوساختار , پايداري حرارتي , خواص مكانيكي
استاد داور :
مرتضي شمعانيان اصفهاني، عباس بهرامي
تاريخ ورود اطلاعات :
1397/01/18
چكيده انگليسي :
118 Fabrication and characterization of nanostructured high entropy alloys AlCoFeNiX Cu Zn by mechanical alloying and evaluation of mechanical properties Seyedeh Mahnaz Sajadi m sajadi@ma iut ac ir Date of Submission 2018 01 14 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Persian Supervisor MohammadReza Toroghinejad Prof toroghi@cc iut ac irAbstractIn this study high entropy alloys AlCoFeNiX Cu Zn were synthesized using mechanical alloyingto investigate the effect of constituent elements on the evolving microstructure and mechanicalproperties The results of X ray diffraction XRD analysis confirmed the formation of solidsolutions after 50 hours of ball milling Changes in the microstructure were evaluated by ScanningElectron Microscopy SEM equipped with Energy dispersive X ray spectroscopy EDS Theinvestigation of phase stability criteria in high entropy alloys Mediama model was performed confirming the formation of solid solutions in all alloys The results were consistent with the resultsof particle diffusion pattern indicating the formation of solid solution phase in the alloys Thermalanalysis was carried out using differential scanning calorimeter DSC and thermal gravimetricanalysis TGA Results showed that while AlCoFeNi and AlCoFeNiCu high entropy alloys havethermal stability 1100 AlCoFeNiZn high entropy alloy is thermally stable up to 450 In orderto obtain a volumetric sample with optimum properties different spark plasma sintering SPS parameters were investigated High entropy alloy powder was consolidated by spark plasmasintering under different conditions temperature pressure pulse and heating cycle time Thehighest attained density in AlCoFeNi AlCoFeNiCu and AlCoFeNiZn alloys were 89 89 and85 respectively The mechanical behavior of the alloys was investigated using hardness test vickers microindentation shear punch and abrasion tests The highest hardness values for zinc containing alloys can be attributed to the presence of BCC solid solution in the microstructure Thehighest amount of final shear stress for copper containing alloy was due to the copperstrengthening mechanism and the formation of a FCC and BCC solid solution phases while thelowest value was measured for zinc containing alloys with BCC structure Wear test results showthat with increasing strength the wear resistance of the alloy decreased but the friction coefficientremained constant The changes in weight loss after 500 m of experiment showed different wearrates in samples The amount of friction coefficient of all samples were low due to surfacecontamination After reducing the contamination the friction coefficient of surfaces reachedconstant values indicating that the wear has reached a stable stage confirming the steady stateregime of the friction coefficient behavior in the samples Key words High entropy alloy mechanical alloying nanostructure thermal stability mechanical properties
استاد راهنما :
محمدرضا طرقي نژاد
استاد مشاور :
فتح الله كريم زاده
استاد داور :
مرتضي شمعانيان اصفهاني، عباس بهرامي
