Experimental study of the effect of FSW tool geometrical ratios on mechanical properties of aluminium joints

نوع: Type: thesis

مقطع: Segment: masters

عنوان: Title: Experimental study of the effect of FSW tool geometrical ratios on mechanical properties of aluminium joints

ارائه دهنده: Provider: Mohammad Sarvi

اساتید راهنما: Supervisors: Dr. Ali Alavi Nia

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: Dr.Amir Hossein Mahmoudi - Dr.Abbas Pak

زمان و تاریخ ارائه: Time and date of presentation: 2023/9/30 17:30

مکان ارائه: Place of presentation: Seminar 1 Mechanics

چکیده: Abstract: Friction stir welding (FSW) is a method for joining two workpieces. In this method, a rotating non-consumable tool is inserted between two fixed workpieces. Then, with the heat caused by the friction between the workpieces and the tool, the metal is heated, and with the rotation and linear movement of the tool, the two pieces are welded together. In this study, the effect of tool geometry on welding quality was investigated. To perform the friction stir process, the 6061 aluminum sheet and tools made of H13 steel were used. The geometrical variables of the tool included pin length, pin diameter, and shoulder diameter, each of which was examined in three different sizes. A total of 27 experiments were done with different tool geometries. After performing the friction stir process on the samples, the properties of the weld zone were studied by conducting tensile tests, microhardness, and metallographic experiments. The results showed that by reducing the grain size, the mechanical properties such as yield stress and hardness improved, which was consistent with the Hall-Petch relationship. Also, by increasing the length of the tool pin, the ultimate strength, yield stress, hardness, and process efficiency increased, and the grain size decreased. In addition, the best mechanical properties were obtained in samples that were made via a tool with a ratio of shoulder diameter to pin diameter of 3. Finally, the sample was made by a tool with a pin length of 4.8 mm, a pin diameter of 6 mm, and a shoulder diameter of 18 mm, with a yield stress of 145 MPa, ultimate strength of 213.3 MPa, hardness of 33.98 Vickers and grain size in the stir zone (SZ) of 3.7 µm, had the best welding quality.

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