Dissimilar Friction Stir Welding of AA2024 and AISI 1018: Microstructure and Mechanical Properties

Abstract

This study investigated the effect of the friction stir welding rotation rate and welding speed on the quality and properties of the dissimilar joints between aluminum and carbon steel. Plates of 4 mm thickness from both AA2024 and AISI 1018 were successfully friction stir butt welded at rotation speeds of 200, 250, and 300 rpm and welding speeds of 25, 50, and 75 mm/min. The joint quality was investigated along the top surface and the transverse cross-sections. Further investigation using scanning electron microscopy was conducted to assess the intermetallic layers and the grain refining in the stir zone. The mechanical properties were investigated using tensile testing for two samples for each weld that wire cut perpendicular to the welding direction and the hardness profiles were obtained along the transverse cross-section. Both the top surface and the transverse cross-section macrographs indicated defect free joints at a rotation rate of 250 rpm with the different welding speeds. The intermetallic compounds (IMCs) formation was significantly affected by the heat input, where there is no formation of IMCs at the Al/steel interfaces when higher traverse speed (75 mm/min) or lower rotation speed (200 rpm) were used, which gave the maximum tensile strength of about 230 MPa at the low rotation speed (200 rpm) along with 3.2% elongation. This is attributed to the low amount of heat input (22.32 J/mm) experienced. At the low traverse speed (25 mm/min and 250 rpm), a continuous layer of Al-rich IMCs FeAl3 is formed at the joint interface due to the high heat input experienced (79.5 J/mm). The formation of the IMCs facilitates fracture and reduced the tensile strength of the joint to about 98 MPa. The fracture mechanism was found to be of mixed mode and characterized by a cleavage pattern and dimples. The hardness profiles indicated a reduction in the hardness at the aluminum side and an increase at the steel side.

The Effect of Temper Condition and Feeding Speed on the Additive Manufacturing of AA2011 Parts Using Friction Stir Deposition

“…FSD as a thermomechanical process is similar to friction stir welding (FSW) [ 29 , 30 , 31 , 32 ] and processing (FSP) [ 28 ] in heat generation, heat dissipation, and heat transfer mechanisms in the stir zone [ 33 , 34 , 35 ]. In the AA2011 AMPs, the heat is generated by dynamic contact friction (DCF) between the consumable tool and AA5083 substrate material.…”

Bobbin Tool Friction Stir Welding of Aluminum Thick Lap Joints: Effect of Process Parameters on Temperature Distribution and Joints’ Properties

“…Table 3 summarizes the BT-FSW process parameters. BT-FSW similar lap joints were carried out using the FSW machine (EG-FSW-M1) [ 21 , 22 , 23 , 24 , 25 , 26 ]. Adaptive fixture was designed and fabricated from steel for BT-FSW purposes.…”

The Applicability of Die Cast A356 Alloy to Additive Friction Stir Deposition at Various Feeding Speeds

“…Among the AM techniques [4], friction stir deposition (FSD) is used instead of fusion-based techniques [5] in the manufacturing of aluminum alloys [6,7], copper alloys [8], and steel [9]. This solid-state metal AM technology is based on friction stirring principles [10][11][12], adding a mechanism of material feeding. In most recent studies, it has been called additive friction stir deposition (AFSD) [13].…”