Microstructure evolution and mechanical properties of high-strength 7075 aluminum alloy during multi-pass hot radial forging process

The 7075 aluminum alloy has exceptional strength, but refining its microstructure and improving its mechanical properties presents considerable challenges. In this study, a hot radial forging process comprising preheating, multi-pass radial forging, and T6 heat treatment, was implemented on 7075 alu...

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Main Authors: Chao Zhang, Kun Li, Shengdun Zhao, Ming Chang, Hong Jiang, Yongfei Wang, Yujian Ren, Dawei Zhang
Format: Article
Language:English
Published: Elsevier 2025-07-01
Series:Journal of Materials Research and Technology
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Online Access:http://www.sciencedirect.com/science/article/pii/S2238785425014929
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author Chao Zhang
Kun Li
Shengdun Zhao
Ming Chang
Hong Jiang
Yongfei Wang
Yujian Ren
Dawei Zhang
author_facet Chao Zhang
Kun Li
Shengdun Zhao
Ming Chang
Hong Jiang
Yongfei Wang
Yujian Ren
Dawei Zhang
author_sort Chao Zhang
collection DOAJ
description The 7075 aluminum alloy has exceptional strength, but refining its microstructure and improving its mechanical properties presents considerable challenges. In this study, a hot radial forging process comprising preheating, multi-pass radial forging, and T6 heat treatment, was implemented on 7075 aluminum alloy rods. The microstructure evolution mechanisms in the edge and core regions of the workpieces were investigated through observations on the changes in grain morphology (grain boundary, size, and orientation) and second phase precipitation. The microhardness and tensile properties of the workpiece were assessed at varying cross-section reduction rates (CSRRs) during radial forging and distinct solution durations during T6 heat treatment. Results demonstrate that preheating considerably enhances the plasticity of the workpiece. During multi-pass radial forging, the key mechanisms of refining microstructure are geometrical dynamic recrystallization and continuous dynamic recrystallization induced by the radial compression of grains and interweaving between adjacent grains. The implementation of T6 heat treatment on the radial forged workpiece facilitates the formation of continuous equiaxed subgrains, the proliferation of fine recrystallized grains and the uniform precipitation of η′ phase. Radial forging combined with T6 heat treatment considerably strengthens the edge region of the workpiece (↑6.7 % in ultimate tensile strength [UTS], ↑33.3 % in elongation) at 30.6 % CSRR, and improves the overall mechanical performance of the workpiece (Edge: ↑5.7 % in UTS, ↑32.3 % in elongation; Core: ↑4.9 % in UTS, ↑40.4 % in elongation) at 55.6 % CSRR. This study may provide an expeditious and flexible manufacturing process for multi-step 7075 aluminum alloy shafts that withstand high loads in lightweighting applications.
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publisher Elsevier
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spelling doaj-art-7b3ff23e5c444ca997275a5fb2fc21842025-08-20T02:09:52ZengElsevierJournal of Materials Research and Technology2238-78542025-07-01371276129610.1016/j.jmrt.2025.06.070Microstructure evolution and mechanical properties of high-strength 7075 aluminum alloy during multi-pass hot radial forging processChao Zhang0Kun Li1Shengdun Zhao2Ming Chang3Hong Jiang4Yongfei Wang5Yujian Ren6Dawei Zhang7School of Mechanical Engineering, Xi'an Jiaotong University, 710049, Xi'an, China; State Key Laboratory of Metal Forming Technology and Heavy Equipment, Xi'an Jiaotong University, 710049, Xi'an, ChinaSchool of Mechanical Engineering, Xi'an Jiaotong University, 710049, Xi'an, ChinaSchool of Mechanical Engineering, Xi'an Jiaotong University, 710049, Xi'an, China; State Key Laboratory of Metal Forming Technology and Heavy Equipment, Xi'an Jiaotong University, 710049, Xi'an, China; Corresponding author. School of Mechanical Engineering, Xi'an Jiaotong University, No 28, Xianning West Road, Xi'an, 710049, Shaanxi, China.School of Mechanical Engineering, Xi'an Jiaotong University, 710049, Xi'an, ChinaSchool of Mechanical Engineering, Xi'an Jiaotong University, 710049, Xi'an, ChinaSchool of Mechanical Engineering, Xi'an Jiaotong University, 710049, Xi'an, China; State Key Laboratory of Metal Forming Technology and Heavy Equipment, Xi'an Jiaotong University, 710049, Xi'an, ChinaSchool of Mechanical Engineering, Xi'an Jiaotong University, 710049, Xi'an, China; State Key Laboratory of Metal Forming Technology and Heavy Equipment, Xi'an Jiaotong University, 710049, Xi'an, ChinaSchool of Mechanical Engineering, Xi'an Jiaotong University, 710049, Xi'an, China; State Key Laboratory of Metal Forming Technology and Heavy Equipment, Xi'an Jiaotong University, 710049, Xi'an, China; Corresponding author. School of Mechanical Engineering, Xi'an Jiaotong University, No 28, Xianning West Road, Xi'an, 710049, Shaanxi, China.The 7075 aluminum alloy has exceptional strength, but refining its microstructure and improving its mechanical properties presents considerable challenges. In this study, a hot radial forging process comprising preheating, multi-pass radial forging, and T6 heat treatment, was implemented on 7075 aluminum alloy rods. The microstructure evolution mechanisms in the edge and core regions of the workpieces were investigated through observations on the changes in grain morphology (grain boundary, size, and orientation) and second phase precipitation. The microhardness and tensile properties of the workpiece were assessed at varying cross-section reduction rates (CSRRs) during radial forging and distinct solution durations during T6 heat treatment. Results demonstrate that preheating considerably enhances the plasticity of the workpiece. During multi-pass radial forging, the key mechanisms of refining microstructure are geometrical dynamic recrystallization and continuous dynamic recrystallization induced by the radial compression of grains and interweaving between adjacent grains. The implementation of T6 heat treatment on the radial forged workpiece facilitates the formation of continuous equiaxed subgrains, the proliferation of fine recrystallized grains and the uniform precipitation of η′ phase. Radial forging combined with T6 heat treatment considerably strengthens the edge region of the workpiece (↑6.7 % in ultimate tensile strength [UTS], ↑33.3 % in elongation) at 30.6 % CSRR, and improves the overall mechanical performance of the workpiece (Edge: ↑5.7 % in UTS, ↑32.3 % in elongation; Core: ↑4.9 % in UTS, ↑40.4 % in elongation) at 55.6 % CSRR. This study may provide an expeditious and flexible manufacturing process for multi-step 7075 aluminum alloy shafts that withstand high loads in lightweighting applications.http://www.sciencedirect.com/science/article/pii/S22387854250149297075 aluminum alloyMicrostructure evolutionHot radial forgingT6 heat treatmentMechanical property
spellingShingle Chao Zhang
Kun Li
Shengdun Zhao
Ming Chang
Hong Jiang
Yongfei Wang
Yujian Ren
Dawei Zhang
Microstructure evolution and mechanical properties of high-strength 7075 aluminum alloy during multi-pass hot radial forging process
Journal of Materials Research and Technology
7075 aluminum alloy
Microstructure evolution
Hot radial forging
T6 heat treatment
Mechanical property
title Microstructure evolution and mechanical properties of high-strength 7075 aluminum alloy during multi-pass hot radial forging process
title_full Microstructure evolution and mechanical properties of high-strength 7075 aluminum alloy during multi-pass hot radial forging process
title_fullStr Microstructure evolution and mechanical properties of high-strength 7075 aluminum alloy during multi-pass hot radial forging process
title_full_unstemmed Microstructure evolution and mechanical properties of high-strength 7075 aluminum alloy during multi-pass hot radial forging process
title_short Microstructure evolution and mechanical properties of high-strength 7075 aluminum alloy during multi-pass hot radial forging process
title_sort microstructure evolution and mechanical properties of high strength 7075 aluminum alloy during multi pass hot radial forging process
topic 7075 aluminum alloy
Microstructure evolution
Hot radial forging
T6 heat treatment
Mechanical property
url http://www.sciencedirect.com/science/article/pii/S2238785425014929
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