Study on dissimilar friction stir butt welding of AA7075-O and AA2024-T4 considering the manufacturing limitation

Abstract

In the present article, the effect of friction stir welding (FSW) parameters on the weldability and the characteristics of dissimilar weld of aluminum alloys, called AA2024-T4 and AA7075-O are investigated. A number of FSW experiments are carried out to obtain high-quality welds by adjusting the rotational and welding speeds. The weldability and blending of two materials are evaluated by using the macrostructural analysis to observe whether making a notch in a threaded cylindrical tool will lead to a better blend rather than the threaded taper tool or it will have no effects. The mechanical properties of the welds are studied through microhardness distribution and tensile tests. Furthermore, the microstructure analysis is performed to study the influence of the pin profile and the rotational speed on the grain size. Moreover, in the present study, one of the most major goals is to obtain high-quality welds by spending as little expenditure as possible. Therefore, it prevents using complicated and insupportable high welding speed equipments.

Effect of cooling media on residual stresses induced by a solid-state welding: underwater FSW

“…Unless, the RS induced at the nugget zone increase up to the level, which can change the fracture location, or the stress concentration arising from the possible weld defects and voids, which occurs in the nugget zone, changes the stress field within the weld zone and makes joints to fracture from the nugget zone. However, the worth noting is that from hardness point of view, the HAZ exhibits the minimum hardness amount the other zones in tempered precipitating aluminum alloys including AA7075-T6 [31,32]. Meanwhile, the previous observations mainly revealed that the minimum hardness in defect-free welds is followed by the fracture [31,32].…”

“…However, the worth noting is that from hardness point of view, the HAZ exhibits the minimum hardness amount the other zones in tempered precipitating aluminum alloys including AA7075-T6 [31,32]. Meanwhile, the previous observations mainly revealed that the minimum hardness in defect-free welds is followed by the fracture [31,32]. However, when a defect in other zones such as the nugget zone is resulted from an inappropriate welding process, the RS field may have considerable effect on the crack growth and consequently the weld strength.…”

Investigation of 7A09 aluminum alloy prepared by continuous variable cross-section direct extrusion (CVCDE)

“…SPD technology which imposes severe shear deformation can refine the material microstructure and improve comprehensive performance. Aluminum alloy with high strength and good mechanical properties is popular in material preparation [1][2][3]. Aluminum alloy SPD representative technology, equal channel angular pressing (ECAP) [4,5], high-pressure torsion (HPT) [6], reciprocating extrusion, multi-direction forging, and twist extrusion are gradually becoming a hot topic of research in this field.…”

Mechanical Properties of Dissimilar Friction Stir Welded Joints between AA7075-O and AA6061-O Alloys

“…AA7075 alloy (Al-Zn-Mg-Cu alloy), which is one of the strongest aluminum alloys, is precipitation hardened wrought material commonly used in aircraft parts, gears and shafts, missile parts, aerospace and defence applications [2]. It has gathered wide acceptance in many structural applications due to its high strength to weight ratio, good resistance to corrosion and natural ageing characteristics [3,4].…”

“…No additive materials, cover gas or flux is used in the process and this makes FSW technology a strong candidate for joining of the aforementioned materials. In addition, several types of joints such as butt and T butt joints or fillet joints can be simply welded by this significant technology [1].AA7075 alloy (Al-Zn-Mg-Cu alloy), which is one of the strongest aluminum alloys, is precipitation hardened wrought material commonly used in aircraft parts, gears and shafts, missile parts, aerospace and defence applications [2]. It has gathered wide acceptance in many structural applications due to its high strength to weight ratio, good resistance to corrosion and natural ageing characteristics [3,4].…”