8511

7892

كارشناسي ارشد

استخراج فلزات

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1392

چهارده،96ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

محمدحسن عباسي، فخرالدين اشرفي زاده

15/11/92

محمد حسين عنايتي، سعيدرضا بخشي

مهندسي مواد

ID7892

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

97The effect of synthesis route on the characteristics of MoSi2 TiB2 nanocomposite pro duced by mechanical alloying for thermal spraying Esmaeil Rostamizadeh e rostami@ma iut ac ir November 24 2013 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisorsMohammad Hasan Abbasi Prof abbasi32@cc iut ac irFakhreddin Ashrafizadeh Prof ashrafif@cc iut ac irAbstractIn this study MoSi2 TiB2 nanocomposites with 10 and 20 wt TiB2 were synthesized andcharacterized by mechanical alloying via three routes In the first route elemental powdersof molybdenum silicon titanium and boron were milled for 60 h In the second route MoSi2 was synthesized first from Mo and Si by 30 h milling and Ti B elemental powderswere added and the mixture was milled for 60 h In the third route MoSi2 was made by 30h milling of Mo and Si and commercial TiB2 was added and milling was continued for 30h Heat treatment at 1000 C for 60 min was carried out on the powders that were producedby three routes The effect of mechanical alloying on grain size and lattice strain was in vestigated by williamson hall method The morphology and microstructure of producedpowders were studied by SEM and EDS The results indicated that the nanocompositepowders synthesized by the first route with 20 wt TiB2 and heat treatment contained onMo5Si3 and MoB phases The results showed that second route required more reaction timethan the first route The results of XRD patterns showed that the produced MoSi2 by threeroutes was mixture and Heat treatment of samples resulted in MoSi2 to MoSi2phase change increase in the grain size and decrease in the micro strain The lattice con stant of MoSi2 was calculated by Nelson Riley method The mechanical properteis ofsamples were determined by hardness test The results indicated that increasing the millingtime increases the hardness of samples due to plastic deformation and work hardening Itwas also found that by adding TiB2 to MoSi2 hardness was increased considerably Ag glomeration process was carried out on the powders to be used in the thermal spray pro cess The spherical degree and particle size distribution of agglomerating was evaluatedusing clemex software The results showed that the nanocomposite powder produced bythe first route had high quality for use in the thermal spray process due to high hardnessand suitable spherical degree of particles Key words Nanocomposite Mechanical alloying agglomeration MoSi2 TiB2

محمدحسن عباسي، فخرالدين اشرفي زاده

محمد حسين عنايتي، سعيدرضا بخشي