Investigation effect of friction stir welding parameters on joinability of aluminum casting alloys

In this work, Al-Cu plates have been joined by friction stir welding with 32mm/min federate and 800, 1000, 1200 rpm spindle speeds. Also, Al alloys with different Cu content have been used as test material. Thus, effect of rotating of tool on joints have been investigated. With this aim, temperature distribution of weld joints, hardness, microstructural characterization and mechanical properties have been investigated. In the tests, weld zones which includes Al/Cu-Heat Affected Zones (HAZ), Al-Cu Thermomechanical affected zones (TMEB), and Al/Cu Weld center have been observed. It is observed that weld center zones compromise of Al/Cu mixtures and grain refinement have been occurred. Rotation of the tool is significant factor affecting grain size in HAZ and weld metal has been monitored. Furthermore, it is observed that rotation of tool has not systematically influenced HAZ and weld metal grain size. As increase in rotation of tool, there have been a rise in temperature at weld metal, still this temperature cannot achieved to melting temperature. In XRD investigations, rise in temperature and stirring of the tool give rise to intermetallic Al2Cu in weld zones. Hardness measurements indicated that hardness of HAZ have lower hardness than base material In this work, tensile tests and bending tests measurements have been executed. The maximum bending strength have been obtained in specimens which posses least Cu content. In tensile results, the maximum tensile strength have been obtained in %4.5-2 Cu added Al alloys.