8635

8016

كارشناسي ارشد

شناسايي و انتخاب و روش ساخت مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1392

پنج،83ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

محمدرضا طرقي نژاد، احمد رضاييان

21/12/92

قاسم ديني، ابوذر طاهري زاده

مهندسي مواد

ID8016

به فارسي و انگليسي: قابل رويت د نسخه ديجيتالي

Manufacturing and microstructure and mechanical investigations of an Al Cu nano composite reinforced by alumina using accumulative roll bonding process ARB Vahid Yousefi Mehr V yousefi@ma iut ac ir January2014 Department of Material Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc language Farsi Supervisors Mohammad Reza Toroghinejad Prof E mail Toroghi@cc iut ac ir Ahmad Rezaeian Assist Prof E mail A rezaeian@cc iut ac ir Abstract In this study dissimilar Al Cu multilayered composite reinforced by alumina particles were successfully produced via accumulative roll bonding process and its properties were characterized Coated Al strips using anodizing process were positioned between two Cu layers to form primary sandwich followed by roll bonding to a specification reduction For synthetizing a composite with acceptable properties effect of different parameters on the bond strength of layers was firstly evaluated These parameters included different reductions varying thickness of oxide film and post roll annealing process The roll bonded strips were then characterized by peeling test and the peeled surfaces were investigated by optical and scanning electron microscopy The peeling test revealed that by increasing the reduction and thickness of the oxide layer the bond strength was increased In order to investigate the parameters affecting Al Cu composite for the second step different amounts of initial metals were produced and annealed for different periods and temperatures Mechanical evaluations revealed that by increasing the amount of Cu in Al matrix the tensile strength was increased while elongation was decreased Furthermore annealing at shorter times deteriorated tensile strength of the composite while the elongation improved while at prolonged times the tensile strength of specimens increased and elongation decreased Also thermal analysis via DSC and phase analysis by XRD revealed that during annealing Al4Cu9 intermetallic was formed After optimizing the best condition for producing Al Cu composite the composite with alumina particles were produced by ARB process up to seven cycles Microstructural evaluation revealed that by increasing ARB cycles more Cu layers fractured and distribution of alumina particles in the matrix was improved Also different mechanical characterizations including tensile bending shear punch and micro hardness tests were conducted on produced composite Tensile test showed that by increasing the ARB cycles up to the third cycle tensile strength was improved after which it was suddenly decreased for the fourth and fifth cycles and finally for the last sixth and seventh ARB cycles it increased Moreover investigation of fractured composites indicated that micro crack formation between the metallic layers and micro void formation at metal particles interfaces resulted in composite fracture Finally mean grain size was investigated for Al and Cu layers by MAUD software Results showed that crystallite size were reached to less than 100 nm after the seventh ARB cycle for both metallic layers Key words Al Cu Al2O3 composite cold roll bonding accumulative roll bonding mechanical investigation microstructure evaluations and annealing treatment

محمدرضا طرقي نژاد، احمد رضاييان

قاسم ديني، ابوذر طاهري زاده