الفهرس 
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Abstract
Friction stir welding (FSW) is a modern welding technique that is attracting researchers‟ interest because of its vast advantages. The method is claimed as environmentally friendly, which is paramount with the rising concerns about the environment. Moreover, FSW is energy efficient and have versatile uses as well as its ability to weld highstrength materials that are hard to be welded using conventional methods.
In the present investigation, AA6063 aluminum alloy plates are
joined using friction stir welding (FSW). The plates are of 12 mm
thickness and in lab joint configuration. This work studies the influences of tool rotational speed and tool traverse speed on mechanical behavior of the AA6063 alloy. The mechanical behavior is assessed by a number of mechanical properties namely; the surface roughness of welding line,
impact strength of weld joint, microstructure of weld joint, microhardness of weld joint, and corrosion resistance of weld joint.
Full factorial experiments are designed to investigate the welding
conditions effect on the mechanical properties. The experiments use 4
levels of rotational speeds 470, 590, 740, and 900 rpm, and 3 levels of the
traverse speed 16, 31.5, and 50 mm/min. The welding process is
performed on CNC milling machine, and welding spots are joined using a
tool with tapered pin profile and flat shoulder. All mechanical properties experiments are performed at specific
conditions and results are evaluated. The impact test is carried out on the
welded specimens at three different temperatures; room temperature, -
30ᵒC, and -60ᵒC. Three specimens are machined in charpy impact test
specimen specification from each combination of welding conditions
joint, and average data are reported. Experiments results reveal that the
highest impact strength is obtained at - 60ᵒC with 107.8 Joule. While the
lowest surface roughness is calculated of 0.522 μm, and the smallest grain size is 18μm. Additionally, the hardness in nugget zone is measured
as 120.36 HV.