بررسي ريز ساختار و خواص مكانيكي نانو كامپوزيت هيبريدي آلومينيوم/آلومينا/كاربيد سيليسيم ساخته شده توسط فرايند نورد تجمعي

چكيده انگليسي :

Evaluation of Microstructure and Mechanical Properties of Nano Hybrid Composite of Aluminum Alumina Siliconcarbide Produced by Accumulative Roll Bonding ARB Azin Ahmadi Azin ahmadi@ma iut ac ir January 14 2013 Department of Materials Engineering Isfahan University of Technology 84156 83111 Isfahan Iran Degree M Sc Language Farsi Supervisor Mohammad Reza Toroghinejad Assoc Prof E mail toroghi@cc iut ac ir Supervisor Abbas Najafizadeh Prof E mail a najafi@cc iut ac ir Abstract In this study two different methods including accumulative roll boning ARB and cross roll accumulative roll bonding CRARB processes were used for the fabrication of Al Al2O3 SiC hybrid composite Anodizing process was used to grow alumina layer on the substrate of aluminum strips to introduce the Al2O3 particles to the matrix Also silicon carbide powder was manually dispersed between aluminum strips ARB and CRARB processes were applied successfully for eight cycles on the samples including aluminum strips alumina layers and siliconcarbide powder Peeling test was used to investigate the effect of different parameters such as reduction in thickness alumina layer thickness and the amount of siliconcarbide powder on the bond strength of Al Al strips Fractured surfaces of the layers after the peeling test were studied by scanning electron microscopy Furthermore microstructural variation of samples within different stage of both ARB and CRARB processes were investigated by sccaning electron microscopy The mechanical properties of produced composites were evaluated by mechanical tests such as tensile test shear punch test and microhardness test Also scanning electron microscopy was applied for the determination of fracture mechanism of the samples after the tensile test Finally microstructure parameters of ARB processed samples were calculated by using MAUD software The results indicated that by increasing the thickness of alumina layers the bond strength of Al Al strips increases However by increasing powder content between strips the bond strength redused Also the bond strength of aluminum layers improved with increasing the thickness reduction Furthermore it was found that by increasing the number of cycles the disributon of the Al2O3 and SiC particles in the aluminum matrix was improved and the porosity between SiC particles and matrix decreases Moreover the tensile strength shear strength and microharness of produced composites were enhanced by proceeding the processes Elongation of composite samples decreased in the first and second steps of composite production by ARB and CRARB processes but it improved with increasing the process cycles during third step In general the distribution of particles and maehanical propertices of the composites produced with CRARB process were better than ARB processed composites In addition investigation of the effect of particle content showed that mechanical propertices of samples improwed by increasing the volume fraction of alumina and siliconcarbide particle up to a specific amount However higher increasing of particle content reduced the thensile strength and shear strength SEM observation of fracture surfaces after tensile test revealed that the failure mode of brocken composites produced by ARB process was shear ductile rupture type The crystallites size composite produced by eight cycles of ARB process was less than 100 nm Keywords Al Al2O3 SiC hyrid composite Accumulative roll bonding ARB Cross Roll Accumulative Roll Bonding CRARB Bond strength Alumina layer Microstructure Mechanical properties Fracture surface PDF created with pdfFactory trial version www pdffactory com

احمدي، آذين

بررسي ريز ساختار و خواص مكانيكي نانو كامپوزيت هيبريدي آلومينيوم/آلومينا/كاربيد سيليسيم ساخته شده توسط فرايند نورد تجمعي

كامپوزيت هيبريدي Al/Al2O3/SiC , نورد تجمعي﴿ARB﴾ و نورد تجمعي متقاطع ﴿CRARB﴾ , استحكام پيوند , لايه آلومينا , سطوح شكست