بررسي ريز ساختار و خواص مكانيكي نانو كامپوزيت هيبريدي آلومينيوم/آلومينا/كاربيد تيتانيم توليد شده توسط فرايندهاي نورد

چكيده انگليسي :

Investigation of microstructure and mechanical properties of Nano hybrid composite of Aluminum Alumina Titanium carbide produced by rolling processes Hajar Farjzadeh dehkordi H Farajzadehdehkordi@ma iut ac ir January 14 2013 Department of Materials Engineering Isfahan University of Technology 84156 83111 Isfahan IranDegree M Sc Language FarsiSupervisor Mohammad Reza Toroghinejad Assoc Prof E mail toroghi@cc iut ac irSupervisor Keyvan Raeissi Assoc Prof E mail k raeissi@cc iut ac irAbstractIn this study Accumulative Roll Boning ARB and anodizing processes were used asuseful proceeses to fabricate the nano Al Al2O3 TiC hybrid composite with highly uniformdistributed reinforcement particles By anodizing the aluminum strips at different times alumina layer with various thicknesses was achieved Using the anodized strips withdifferent thicknesses of alumina layer and adding TiC particles Al Al2O3 TiC hybridcomposites were fabricated with different volume fractions of alumina and TiC particles Before the fabricating hybrid composite the peeling test was utilized for evaluating theeffective parameters on bond strength of aluminum aluminum layers The results of thistest demonstrated that increasing the thickness of alumina layer causes to enhance the bondstrength of Al Al layers and by increasing the volume fraction of TiC particles the bondstrength is declined Microstructure of composites in different cycles of ARB process wasevaluated by scanning electron microscopy SEM The microscopic observations showedthat after one cycle departing and fracturing phenomena occurs in brittle alumina layer andby increasing the number of rolling cycles the alumina fragments break down to finerparticles By applying eight rolling cycles the distribution of reinforcement particles Al2O3 and TiC in aluminum matrix became completely uniform For evaluating themechanical properties of produced hybrid composite in different cycles of process thetensile test shear punch test and microhardness test were utilized It was found that if thenumber of ARB cycles is increased the mechanical properties of the hybrid compositesuch as tensile strength ultimate shear strength and microhardness were enhancedconsequently Elongation of composite samples decreased dramatically in the first and twosteps of composite production initial four cycles and it improved by progressing theprocess to 8th cycle The results showed that for composites produced by ARB process thepresence of up to 1 6 vol alumina and 1 vol of TiC particles in aluminum matrixconsiderably enhance the tensile strength of hybrid composite Whereas increasing theamount of alumina and TiC particles more than the said volume fractions declines thetensile and shear strength SEM observations of fracture surfaces after tensile test revealedthat the failure mode in produced composites by ARB process was shear ductile rupture The crystallites size that measured by MAUD software for aluminum and the compositeproduced by eight cycles of ARB process reached to 155 nm and 75 nm respectively Finally Al Al2O3 TiC hybrid composite was produced by Cross Roll Accumulative Rollbonding CR ARB process Comparsion of microstructure of ARB and CR ARBprocessed composites indicated that the distribution of particles in CR ARB processedcomposite is more uniform than the ARB processed composite The results of investigationof mechanical properties showed that the CR ARB processed composites have bettermechanical properties as tensile and ultimate shear strength microhardness and elongation Keywords Hybrid composites Al Al2O3 TiC Accumulative roll bonding ARB Cross roll accumulative roll bonding CR ARB and Mechanical properties

فرج زاده دهكردي، هاجر

بررسي ريز ساختار و خواص مكانيكي نانو كامپوزيت هيبريدي آلومينيوم/آلومينا/كاربيد تيتانيم توليد شده توسط فرايندهاي نورد

فرايند نورد تجمعي﴿ARB﴾ , فرايند نورد تجمعي متقاطع ﴿‍CR-ARB﴾ و خواص مكانيكي