توليد و مشخصه يابي نانو كامپوزيت Al-Mg-Si/Al2O3

چكيده انگليسي :

Preparation and Characterization of Al Mg Si Al2O3 Nanocomposites Nazaneen Hosseini Email address nazaneen hosseini@ma iut ac ir Date of Submission Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor s Name Fath Allah karimzadeh Associate Professor karimzadeh f@cc iut ac ir Mohammad Hasan Abbasi Professor abbasi32@cc iut ac irAbstractAluminum based metal matrix composites MMCs are ideal materials for structural applications in the aircraftand automotive industries on account of their excellent mechanical characteristics and low cost componentproduction with respect to other alloys Aluminum metal matrix composites are light weight and have highstrength and noticeable specific elastic modulus In present study nanocomposites of Al6061 alloy reinforced byAl2O3 were produced and optimized using ball milling and hot pressing method To produce nanostructuredAl6061 milling up to 30 hours was performed on initial Al6061 chips with an average particle and grain size ofabout 500 m and 130 m respectively A planetary ball mill with the rotational speed of 500 rpm ball to powderweight ratio of 10 1 high purity argon protective atmosphere and 0 1wt stearic acid was employed Morphological and structural changes of Al6061 were examined during mechanical milling using ScanningElectron Microscopy SEM observations and X ray Diffraction XRD analysis Moreover thermal stability andstructural changes of nanostructured Al6061 were evaluated via isothermal heat treatment at varioustemperatures for different times 0 5 vol Al2O3 nanoparticles which were dispersed ultrasonically were thenadded to the 15h milled Al6061 powders To achieve a good physical contact between the reinforcements andmatrix these mixtures were again milled up to 15 hours Mechanical milling of nanocomposite powders for 15h hot pressing at 400 C and 128MPa for 0 5h was selected as optimized parameters for bulk nanocomposite andnanostructured preparation In order to probe the effect of hot pressing on structural changes XRD analysis wasdone on nanocomposite samples before and after consolidation Variation of relative density of consolidatedsamples versus Al2O3 nanoparticles volume percent was measured using Archimedes technique Hardness andcompression tests were applied on bulk samples in order to evaluate their mechanical properties Wear behaviorof nanocomposites were characterized using pin on disk test method as well Moreover nanocomposites with3vol Al2O3 in the micron sizes were produced and their wear behavior was investigated as a result acomparison between tribological behavior of Al6061 3vol Al2O3 nanocomposites with nano and micro sizereinforcement particles was done The outcomes showed that Mechanical milling applied on Al6061 chips for30h resulted in particles size reduction from 500 m to 10 m so that equiaxed morphology was achieved forpowder particles Al grain size and lattice strain decreases and increases to 35nm and 0 43 respectively Investigation of grain growth kinetics showed that nanostructured Al6061 had high thermal stability so that Algrain size remained in nanosized scale 60 nm even after heating at 550 C for 3h With 1 3 vol Al2O3nanoparticles addition relative density remained at 98 and hardness value increased from 157HV to 230HV Ultimate compressive strength of nanocomposites found a maximum value of 630MPa at 3 vol Al2O3nanoparticles addition which were 475 105 and 9 higher than that for Al6061 O coarse grained Al6061 inannealed condition Al6061 T6 coarse grained Al6061 in artificially aged condition through T6 temper andnanostructured Al6061 Furthermore Young s modulus value was increased from 68 9GPa for nanostructuredAl6061 to 78 3GPa at 3 volume percent of Al2O3 nanoparticles With addition of 5vol Al2O3 nanoparticles ultimate compressive strength declined to 550MPa additionally Young s modulus value decreased due to thepresence of porosity and micro crack Wear rate of nanost

حسيني نهوجي، نازنين السادات

توليد و مشخصه يابي نانو كامپوزيت Al-Mg-Si/Al2O3

نانو كامپوزيت آلياژ Al6061 , نانو ذرات آلومينا , آسياب كاري مكانيكي , پرس داغ , رفتار سايشي , خواص فشاري