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This work systematically investigates the interface behavior and impact properties of the keyhole-free friction stir spot welding (FSSW) of a dissimilar metal AA6082-T4 Al alloy and DP600 galvanized steel. The keyhole is eliminated by pin retraction technology. The welding process is in accordance with the welding temperature curve and the maximum temperature of the periphery of the shoulder, measured at about 500 °C. The transition layers were formed at the interface, in which the Al, Fe, and Zn elements form an inhomogeneous diffusion. A cloud cluster-like mechanical mixing of the Al and steel components is formed in the stirring zone. The impact toughness of the specimen with a welding parameter of 1000 rpm is the best. To a certain extent, the factors affecting the impact energy are not the maximum impact load but the maximum impact deformation. The maximum impact deformation directly reflects the post-crack propagation energy, which significantly affects its impact toughness. In addition, the impact fracture showed a mixed ductile and brittle fracture mode with a brittle–ductile transition zone. Most of the impact energy was absorbed by the ductile fracture.
Zhongke Zhang; Yang Yu; Huaxia Zhao; Xijing Wang. Interface Behavior and Impact Properties of Dissimilar Al/Steel Keyhole-Free FSSW Joints. Metals 2019, 9, 691 .
AMA StyleZhongke Zhang, Yang Yu, Huaxia Zhao, Xijing Wang. Interface Behavior and Impact Properties of Dissimilar Al/Steel Keyhole-Free FSSW Joints. Metals. 2019; 9 (6):691.
Chicago/Turabian StyleZhongke Zhang; Yang Yu; Huaxia Zhao; Xijing Wang. 2019. "Interface Behavior and Impact Properties of Dissimilar Al/Steel Keyhole-Free FSSW Joints." Metals 9, no. 6: 691.
A plasma arc welding (PAW)-tungsten inert gas (TIG) hybrid welding process is proposed to weld pure nickel. In PAW-TIG welding, the arc of the PAW was first to be ignited, then TIG was ignited, while in PAW welding, only the PAW arc was launched. This paper investigated the effect of different welding processes on electrochemical and corrosion performance of between a pure nickel joint and a base metal in an aerated 1 M NaCl solution, respectively. The average grain size of the joint fabricated by PAW welding (denoted as JP joint) is 463.57 μm, the joint fabricated by PAW-TIG welding(denoted as JP-T joint) is 547.32 μm, and the base metal (BM) is 47.32 μm. In this work, the passivity behaviors of samples were characterized for two welding processes by electrochemical impedance spectroscopy (EIS), open circuit potential versus immersion time (OCP-t), and the potentiodynamic polarization plots. EIS spectra, attained with different immersion times, were analyzed and fitted by an equivalent electrical circuit. Photomicrographs of BM, JP, and JP-T were also taken with a scanning electron microscope (SEM) to reveal the morphological structure of the pit surfaces. Electrochemical tests show that the sequence of the corrosion resistance is BM > JP > JP-T. The size and quantity of the hemispherical corrosion pits of all samples are different. The corrosion morphology observations found a consistency with the consequence of the electrochemical measurements. The results show that an increase of the grain dimensions due to different heat treatments decreased the pure nickel stability to pitting corrosion.
Xijing Wang; Boshi Wang; Liangliang Zhang; Chao Yang; Yan Yang. Effect of Different Welding Processes on Electrochemical and Corrosion Behavior of Pure Nickel in 1 M NaCl Solution. Metals 2017, 7, 532 .
AMA StyleXijing Wang, Boshi Wang, Liangliang Zhang, Chao Yang, Yan Yang. Effect of Different Welding Processes on Electrochemical and Corrosion Behavior of Pure Nickel in 1 M NaCl Solution. Metals. 2017; 7 (12):532.
Chicago/Turabian StyleXijing Wang; Boshi Wang; Liangliang Zhang; Chao Yang; Yan Yang. 2017. "Effect of Different Welding Processes on Electrochemical and Corrosion Behavior of Pure Nickel in 1 M NaCl Solution." Metals 7, no. 12: 532.
The corrosion behavior of keyhole-free friction stir spot welded joints of dissimilar 6082 aluminum alloy and DP600 galvanized steel in 3.5% NaCl solution has been investigated by the immersion test and electrochemical analysis. The surface of the aluminum alloy produced exfoliation and pitting corrosion. The pitting occurred seriously on the interface of the 6082 aluminum alloy, but the steel had no corrosion. The corrosion galvanic couples were formed between elements of Si and Fe with a high electrode potential, and Mg and Al with a low electrode potential, around them. Mg and Al elements of Mg2Si and Si-containing solid-solution phase α (Al) preferentially became an anodic dissolution and formed exfoliation corrosion around the Si elements. Fe-rich phase θ (Al3Fe) as the cathode caused corrosion of Mg and formed pitting around Mg-rich phase β (Al3Mg2) as the anode. The sequence of the corrosion resistance of different areas of the joints (with decreasing corrosion resistance) was WNZ (Weld Nugget Zone) > TMAZ (Thermo-mechanically Affected Zone) > BM (Base Metal) > HAZ (Heat-affected Zone). The joints of keyhole-free FSSW (Fiction Stir Spot Welding) of dissimilar 6082 aluminum alloy and DP600 galvanized steel have better corrosion resistance than base metal in 3.5% NaCl solution.
Zhong-Ke Zhang; Yang Yu; Jian-Fei Zhang; Xi-Jing Wang. Corrosion Behavior of Keyhole-Free Friction Stir Spot Welded Joints of Dissimilar 6082 Aluminum Alloy and DP600 Galvanized Steel in 3.5% NaCl Solution. Metals 2017, 7, 338 .
AMA StyleZhong-Ke Zhang, Yang Yu, Jian-Fei Zhang, Xi-Jing Wang. Corrosion Behavior of Keyhole-Free Friction Stir Spot Welded Joints of Dissimilar 6082 Aluminum Alloy and DP600 Galvanized Steel in 3.5% NaCl Solution. Metals. 2017; 7 (9):338.
Chicago/Turabian StyleZhong-Ke Zhang; Yang Yu; Jian-Fei Zhang; Xi-Jing Wang. 2017. "Corrosion Behavior of Keyhole-Free Friction Stir Spot Welded Joints of Dissimilar 6082 Aluminum Alloy and DP600 Galvanized Steel in 3.5% NaCl Solution." Metals 7, no. 9: 338.
Contrast experiments of lap joints among dissimilar AZ31B Mg alloy, Mg99.50, zinc-coated DP600 sheet, and non-zinc-coated DP600 sheet were made by friction stir keyholeless spot welding (FSKSW) and vacuum diffusion welding (VDW), respectively. Scanning electron microscopy (SEM) and energy disperse spectroscopy (EDS) were used to investigate the microstructures and components of the joints welded. The experimental results show that the FSKSW bonding method is a kind of compound mode that contains a mechanical connection and element diffusion fusion connection, in which mechanical connection has the main decisive function on joints of Mg/steel. Elements diffusion exists in the interfacial region of the joints and the elements diffusion extent is basically the same to that of VDW. The elements’ diffusion in Mg/steel using FSKSW is defined in the reaction between small amounts elements of the base metal and zinc-coated metals. The intermetallic compounds and composite oxide perform some reinforcement on the mechanical connection strength.
Xiao Liu; Xijing Wang; Boshi Wang; Liangliang Zhang; Chao Yang; Tingxi Chai. The Role of Mechanical Connection during Friction Stir Keyholeless Spot Welding Joints of Dissimilar Materials. Metals 2017, 7, 217 .
AMA StyleXiao Liu, Xijing Wang, Boshi Wang, Liangliang Zhang, Chao Yang, Tingxi Chai. The Role of Mechanical Connection during Friction Stir Keyholeless Spot Welding Joints of Dissimilar Materials. Metals. 2017; 7 (6):217.
Chicago/Turabian StyleXiao Liu; Xijing Wang; Boshi Wang; Liangliang Zhang; Chao Yang; Tingxi Chai. 2017. "The Role of Mechanical Connection during Friction Stir Keyholeless Spot Welding Joints of Dissimilar Materials." Metals 7, no. 6: 217.