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Dr. Zhang Zhongke
School of Materials Science and Engineering, Lanzhou University of Technology

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Research Keywords & Expertise

0 Friction Stir Welding
0 Aluminum alloy
0 Friction plug welding
0 dissimilar metals
0 fatigue properties

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Accepted manuscript
Published: 26 March 2021 in Materials Research Express
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Microcrystalline phosphor copper balls with a diameter of 28 mm were prepared via continuous extrusion upsetting. Optical microscopy and electron backscatter diffraction were used to study the microstructural evolution of phosphor copper balls during the formation process. In addition, the hardness distribution and tensile properties were tested. The results show that fine dynamic recrystallisation grains and twins were formed after continuous extrusion and that the grains were further refined after upsetting. After continuous extrusion upsetting, there were typical , , and fibre textures, and the proportions of these three textures in the individual samples were different. The change in microhardness was affected by the microstructure. The increase in the hardness value from casting and continuous extrusion upsetting was owing to pronounced grain refinement. The grain sizes from the centre to the edge were similar, and the grain refinement was more uniform. Notably, the grain size of the extruded rod was still fairly uniform from the centre to the edge in the radial direction. It can be concluded that the continuous extrusion-upsetting phosphor copper anode is more conducive to the formation of black film, that is, it is more suitable for electroplating anode material.

ACS Style

Zhongke Zhang; Zhao Li; Changzhong Zhao. Study on the microstructure and properties of a phosphor copper ball during its formation process. Materials Research Express 2021, 8, 046508 .

AMA Style

Zhongke Zhang, Zhao Li, Changzhong Zhao. Study on the microstructure and properties of a phosphor copper ball during its formation process. Materials Research Express. 2021; 8 (4):046508.

Chicago/Turabian Style

Zhongke Zhang; Zhao Li; Changzhong Zhao. 2021. "Study on the microstructure and properties of a phosphor copper ball during its formation process." Materials Research Express 8, no. 4: 046508.

Journal article
Published: 30 October 2020 in Metals
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The response surface analysis method was used to systematically study the effect of various parameters on the tensile strength of 6082 aluminum alloy friction plug welding (FPW) joints in this work. The fluidity of the joint and microstructure were observed with a metallurgical microscope. Combined with the temperature field and force analysis, the reason why the root of the joint appears as a weak zone was explained. The results showed that the degree of influence on the tensile strength of FPW joints was rotational speed > upsetting speed > welding time. The optimal FPW joint was obtained when the rotational speed was 2254 rpm, the upsetting speed was 2 mm/s, and the welding time was 25 s, so the tensile strength could reach 262.34 MPa. The microstructure of the FPW joint appeared heterogeneous. According to the different plastic metal fluidities of the joint, it could be divided into four areas. The interaction force at the friction interface was not strong at the root of the FPW joint, so the root often becomes the weak area of the FPW joint.

ACS Style

Zhongke Zhang; Xuanbai Li; Zaolong Zhao; Changming Jiang; Huaxia Zhao. Process Optimization and Formation Analysis of Friction Plug Welding of 6082 Aluminum Alloy. Metals 2020, 10, 1454 .

AMA Style

Zhongke Zhang, Xuanbai Li, Zaolong Zhao, Changming Jiang, Huaxia Zhao. Process Optimization and Formation Analysis of Friction Plug Welding of 6082 Aluminum Alloy. Metals. 2020; 10 (11):1454.

Chicago/Turabian Style

Zhongke Zhang; Xuanbai Li; Zaolong Zhao; Changming Jiang; Huaxia Zhao. 2020. "Process Optimization and Formation Analysis of Friction Plug Welding of 6082 Aluminum Alloy." Metals 10, no. 11: 1454.

Journal article
Published: 23 September 2020 in Materials
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The energy evolution, fatigue life and failure behaviour of dissimilar Al/steel keyhole-free Friction stir spot welding (FSSW) joints were studied under different fatigue loads. The absorption energy of fatigue fracture, the fracture mechanism and the sensitivity of the fatigue limits to the fatigue load parameters were analysed. It was found that the stress ratio R determines the fatigue limit Ff, while the fatigue limit Ff is not sensitive to the loading frequency. The high-frequency fatigue load will increase the displacement deformation μ and fatigue fracture absorption energy Ea of the spot-welded joint, which are larger under asymmetric fatigue loading than those under symmetrical fatigue loading. At the same time, the symmetrical fatigue load can form the steady-state hysteresis loop, while asymmetric fatigue loading cannot, but asymmetric fatigue loading exhibits the displacement increment of fatigue softening. The fracture failure of spot-welded joints is a multiple crack source and the mixed-mode of ductile and brittle fracture mechanism, which exhibits typical fatigue striations in the fatigue fractures.

ACS Style

Zhongke Zhang; Yang Yu; Huaxia Zhao; Hui Tong. Effect of Loading Methods on the Fatigue Properties of Dissimilar Al/Steel Keyhole-Free FSSW Joints. Materials 2020, 13, 4247 .

AMA Style

Zhongke Zhang, Yang Yu, Huaxia Zhao, Hui Tong. Effect of Loading Methods on the Fatigue Properties of Dissimilar Al/Steel Keyhole-Free FSSW Joints. Materials. 2020; 13 (19):4247.

Chicago/Turabian Style

Zhongke Zhang; Yang Yu; Huaxia Zhao; Hui Tong. 2020. "Effect of Loading Methods on the Fatigue Properties of Dissimilar Al/Steel Keyhole-Free FSSW Joints." Materials 13, no. 19: 4247.

Journal article
Published: 18 June 2019 in Metals
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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.

ACS Style

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 Style

Zhongke 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 Style

Zhongke 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.

Journal article
Published: 01 September 2017 in Metals
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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.

ACS Style

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 Style

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 (9):338.

Chicago/Turabian Style

Zhong-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.