Effects of hot extrusion and heat treatment on microstructure and properties of industrial large-scale spray-deposited 7055 aluminum alloy

Yang, Yugui; Zhao, Yutao; Kai, Xizhou; Zhang, Zhen; Zhang, Hao; Tao, Ran; Chen, Gang; Yin, Houshang; Wang, Min

doi:10.1088/2053-1591/aaa56b

Cited by 14 publications

(9 citation statements)

References 43 publications

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“…In this work, the solidification rate was estimated as 10 3 -10 4 °C/s based on the parameters listed in Table 1, which provided sufficient cooling rate to solidify the melt within one second. The extreme fast cooling rate forced the crystallization of partial melt to occurr directly from the liquid state without generating dendrites; similar result was found in previous reports [4,5,9]. As a result, equiaxed grains with average size 42 ± 1.2 μm were obtained after the spray deposition, as illustrated in Figure 1.…”

Section: Mechanism Of Microstructure Evolution During Spray Depositiosupporting

confidence: 86%

“…A newly feasible short routine, heat treatment at 450 • C /6 h + 470 • C/1 h following the hot extrusion, proved capable of obtaining a homogeneous microstructure for the spray deposited aluminum alloy 7055. macro segregation could be improved by long-time homogenization heat treatment after casting, but it took tremendous power and time to achieve a uniform distribution of elements. It was well accepted that the diffusion of atoms would be accelerated under the combined effects of heat and stress [5]. However, the cast billet cannot be directly deformed due to the existence of macro segregation and casting defects, i.e., voids, concentration of elements, which would lead to the occurrence of cracks if not controlled properly.…”

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confidence: 99%

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Hot Extrusion Enhanced Homogenization of Microstructure in a Spray Deposition Aluminum Alloy

Sheng

Yang

et al. 2020

Metals

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Homogeneous heat treatment serves the significant roles in eliminating the segregation and tuning the microstructure of alloy ingot. It usually cost tremendous power and time to achieve a homogeneous microstructure for aluminum alloys. In this article, the hot extrusion was directly introduced on the spray deposited aluminum alloy 7055 ingot before performing heat treatment to explore the newly feasible homogeneous routine. Equiaxed grains without dendrites or PPB were obtained in our current parameters of spray deposition, which allowed the as-deposited alloy to be deformed without being subjected to pre-homogeneous heat treatment. Significant amount of stored energy was produced during hot extrusion at 420 • C with area reduction ratio of 6.25, which effectively promoted the homogeneity of microstructure and reduced significantly the heat treatment time. A newly feasible short routine, heat treatment at 450 • C /6 h + 470 • C/1 h following the hot extrusion, proved capable of obtaining a homogeneous microstructure for the spray deposited aluminum alloy 7055. macro segregation could be improved by long-time homogenization heat treatment after casting, but it took tremendous power and time to achieve a uniform distribution of elements. It was well accepted that the diffusion of atoms would be accelerated under the combined effects of heat and stress [5]. However, the cast billet cannot be directly deformed due to the existence of macro segregation and casting defects, i.e., voids, concentration of elements, which would lead to the occurrence of cracks if not controlled properly. Thus, the as-cast aluminum alloy 7055 was usually subjected to homogeneous heat treatment at 46-47 • C for 24 h before deformation [6].Fortunately, spray deposition, a rapid solidification process, was proposed in the 1960s and was firstly applied in fabrication of super-high strength aluminum alloy in the 1990s [7,8]. With the assistance of spray deposition method, the aluminum alloy with high alloying could be produced with segregation being controlled at the micro-scale level. In this situation, the as-deposited alloy could be deformed under controllable parameters without being subjected to pre-homogenization heat treatment [9]. Recently, significant efforts have been made to study the hot deformation behaviors [10][11][12][13][14][15], quenching sensitivity [16][17][18][19], corrosion resistance [20-23] and weldability [24-29] of 7055. However, few reports were concerned with the improvement of homogenization in microstructure with less energy or short processes. In this article, hot extrusion was introduced to directly extrude the billet after spray deposition, wherein the microstructure evolution and corresponding mechanism during hot deformation and extrusion were uncovered. The subsequent heat treatment was employed to evaluate the effects of parameters on microstructure evolution of the hot-extruded alloy. Significant amount of stored energy was produced during hot extrusion at 420 • C with the area reduction ratio of 6.25, whic...

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Section: Mechanism Of Microstructure Evolution During Spray Depositiosupporting

confidence: 86%

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confidence: 99%

Hot Extrusion Enhanced Homogenization of Microstructure in a Spray Deposition Aluminum Alloy

Sheng

Yang

et al. 2020

Metals

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“…As the temperature decreases, the nuclei grow and merge with each other at the interface, developing to the morphology of the equiaxed grains. [11] In addition, the composition distribution has also been changed in as-deposited 7055 alloy, compared to the as-cast 7055 alloy. Figure 3 clearly shows the segregation of zirconium in the as-cast 7055 alloy, but which is not taking place in the as-deposited 7055 alloy.…”

Section: Discussionmentioning

confidence: 99%

“…Most importantly, a uniform distribution of chemical composition and microstructure can be obtained because of the rapid solidification that is an inherent feature of the spray deposition process. [7][8][9][10][11] Therefore, the spray forming technology possibly provides an alternative route to develop high-strength aluminum alloys.…”

Section: Introductionmentioning

confidence: 99%

Microstructure Evolution and Recrystallization Resistance of a 7055 Alloy Fabricated by Spray Forming Technology and by Conventional Ingot Metallurgy

Xie

Jia

Xiang

et al. 2020

Metall Mater Trans A

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The effect of different fabricating processes (spray forming and conventional casting) and homogenization treatment on the microstructure of an 7055 alloy was investigated by optical microscopy (OM), scanning electron microscopy (SEM), electron probe X-ray micro-analyzer (EPMA), and transmission electron microscopy (TEM). It was found that the grain size of the as-deposited (spray formed) 7055 alloy had half the size as that of the as-cast 7055 alloy and there was no Al 2 CuMg phase that embedded in the coarse Mg(Zn, Cu, Al) 2 phase distributed along the grain boundaries in the as-deposited 7055 alloy. No segregation of zirconium was observed in the as-deposited 7055 alloy. After homogenization heating at 350°C/5 hours + 470°C /24 hours, Al 3 Zr dispersoids were inhomogeneously distributed within grains in the traditionally cast 7055 alloy, while more homogeneously distributed within grains in the spray-formed 7055 alloy. Compared with the traditional cast 7055 alloy, the uniform distribution of Al 3 Zr dispersoids in the spray-formed 7055 alloy retards recrystallization more effectively. This investigation highlights the advantage of spray forming technology on improving microstructure of a 7055 alloy.

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“…The state-of-the-art trend in improving the structure and properties of commercial alloys is the application of methods of severe plastic deformation, the best-studied ones being equal-channel angular pressing (ECAP) [12][13][14], equal channel angular extrusion (ECAE) [15][16][17][18], and torsion in Bridgman anvils (HPT) [19][20][21]. New SPD methods have been developed in recent years.…”

Section: Introductionmentioning

confidence: 99%

Effect of Severe Plastic Deformation on Structure Refinement and Mechanical Properties of the Al-Zn-Mg-Fe-Ni Alloy

Бродова

Rasposienko

Ширинкина

et al. 2021

Metals

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This paper identifies the mechanisms of phase and structural transformations during severe plastic deformation by shearing under pressure (high-pressure torsion) of an Al-Zn-Mg-Fe-Ni-based aluminum alloy depending on different initial states of the material (an ingot after homogenizing annealing and a rod produced by radial-shear rolling). Scanning and transmission electron microscopy are used to determine the morphological and size characteristics of the structural constituents of the alloy after high-pressure torsion. It has been found that, irrespective of the history under high-pressure torsion, fragmentation and dynamic recrystallization results in a nanostructural alloy with a high microhardness of 2000 to 2600 MPa. Combined deformation processing (high-pressure torsion + radial-shear rolling) is shown to yield a nanocomposite reinforced with dispersed intermetallic phases of different origins, namely Al9FeNi eutectic aluminides and MgZn2, Al2Mg3Zn3, and Al3Zr secondary phases. The results of uniaxial tensile testing demonstrate good mechanical properties of the composite (ultimate tensile strength of 640 MPa, tensile yield strength of 628 MPa, and elongation of 5%).

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Effects of hot extrusion and heat treatment on microstructure and properties of industrial large-scale spray-deposited 7055 aluminum alloy

Cited by 14 publications

References 43 publications

Hot Extrusion Enhanced Homogenization of Microstructure in a Spray Deposition Aluminum Alloy

Hot Extrusion Enhanced Homogenization of Microstructure in a Spray Deposition Aluminum Alloy

Microstructure Evolution and Recrystallization Resistance of a 7055 Alloy Fabricated by Spray Forming Technology and by Conventional Ingot Metallurgy

Effect of Severe Plastic Deformation on Structure Refinement and Mechanical Properties of the Al-Zn-Mg-Fe-Ni Alloy

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