7549

7021

كارشناسي ارشد

جوشكاري

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1391

چهارده،94ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

مرتضي شمعانيان، حسين ادريس

8/12/91

محمدرضا طرقي نژاد، علي اشرفي

مهندسي مواد

ID7021

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

95 Friction Stir Welding FSW of Al B4C Nanocomposite Produced by Accumulative Roll Bonding ARB and Joint Properties Evaluation Alireza Moradi A moradifaradonbeh@ma iut ac ir Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Morteza Shamanian shamanian@cc iut ac ir Hossein Edris h edris@cc iut ac ir Abstract In this study Al 4 vol B4C composite was produced by accumulative roll bonding process after 10 consecutive cycles Then Friction Stir Welding of composite samples was performed with tool rotational speeds of 560 710 and 900 rpm and welding speeds of 100 200 and 300 mm min In order to investigate the influences of pin profile on microstructure and mechanical properties 4 different pin geometries cylindrical square triangular and hexagonal were selected to fabricate the joints at 900 rpm 300 mm min condition The composite microstructure showed that after 10 ARB cycles the reinforcement particles were fine and distributed uniformly in the aluminum matrix Tensile strength and hardness of produced composite were about 2 9 and 2 4 times as high as that of the annealed pure aluminum respectively while the elongation decreased from 41 to 8 5 Fracture surface of composite samples showed ductile dimples Due to the low welding speed and high pressure tools on composite layer structure the joining of composites at different rotational speed and also at welding speed of 100 mm min was not successfully performed Voids were observed in the stir zone of welds using welding speed of 200 300 mm min at 900 rpm that strongly decreased tensile strength Using greater rotational speed sufficient heat input was provided for material flow during FSW and desirable joints were obtained Results showed that the role of heat input and final grain size are more effective than that of the reinforcement size and distribution Joints obtained at 900 rpm 200 mm min welding parameter showed the least tensile strength and hardness and the most elongation between other welding parameters whereas the most tensile strength and hardness and the lowest elongation were achieved in the joint obtained at 710 rpm 300 mm min condition Fractography of the tensile fracture surfaces of welded samples revealed ductile dimples which were grown and deeper by increase rotational speed or decrease welding speed Microstructural evolution of welded samples by various pin geometries showed that the most fragment and distribution of reinforcement particles were obtained by square pin and also the most tensile strength hardness and elongation were achieved in the joint obtained by this pin Deep voids were observed in stir zone of hexagonal pin which revealed the least tensile strength hardness and elongation Key words Accumulative roll Composite Friction stir welding Heat input Microstructure Mechanical properties Tool pin geometry

مرتضي شمعانيان، حسين ادريس

محمدرضا طرقي نژاد، علي اشرفي