Authors: S D Ji X C Meng Z W Li L Ma S S Gao
Publish Date: 2015/10/01
Volume: 84, Issue: 9-12, Pages: 2391-2399
Abstract
Vertical compensation friction stir welding VCFSW is successfully applied to weld 7N01T4 aluminum alloy and effects of welding speed on joint quality are investigated The results show that when compensation strip width is 1 mm the defectfree joint is obtained at the welding speed of 50 mm/min and constant rotational velocity of 2000 rpm Moreover the intercalation lamellae structure formed in nugget zone NZ can reveal material flow behavior clearly As strip width increases to 15 mm it is difficult to attain sound joint Decreasing welding speed is beneficial to surface formation of VCFSW joint The increase of welding speed decreases tensile strength and elongation of joint At the welding speed of 50 mm/min and strip width of 1 mm the tensile strength and elongation of VCFSW joint are 2957 MPa and 67 equivalent to 66 and 394 of BM respectively while fracture surface of joint presents typical ductile fracture The hardness distribution of joint shows typical W shape and the hardness of NZ exhibits uniform distribution
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