Al-zn-mg-cu alloy with reduced coarse grain layer thickness and method of manufacture

By optimizing the composition and process parameters of Al-Zn-Mg-Cu alloys, especially the content of Mn, Cr, and Zr and multi-stage solid solution treatment, the problem of excessive coarse grain layer thickness in high-alloy Al-Zn-Mg-Cu alloys during extrusion was solved, resulting in aluminum alloy materials with high strength and uniform properties.

CN122081733APending Publication Date: 2026-05-26SHANDONG HONGQIAO LIGHTWEIGHT TECHNOLOGY CO LTD +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2026-03-19
Publication Date
2026-05-26

AI Technical Summary

Technical Problem

Existing technologies struggle to effectively control the layered/ring-shaped coarse grain structure on the surface of Al-Zn-Mg-Cu alloys with a total alloying element content >12wt% during extrusion, leading to uneven performance, reduced fatigue life, and anisotropy issues.

Method used

By optimizing the content of elements Mn, Cr, and Zr, and combining strict control of the extrusion process with multi-stage gradient heating solution treatment, including bipolar preheating, reverse extrusion, multi-stage solution treatment, and artificial aging treatment, the thickness of the coarse grain layer can be reduced.

Benefits of technology

It achieves a coarse grain layer thickness of <0.2mm, improves the uniformity of properties between the material surface and core, and has excellent tensile strength and elongation, thereby enhancing the overall performance and stability of the material in use.

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Abstract

This invention discloses an Al-Zn-Mg-Cu alloy with reduced coarse grain layer thickness and its preparation method. The alloy is composed of the following components by mass percentage: Si: ≤0.10%, Fe: ≤0.10%, Cu: 1.0-1.5%, Mn: ≤0.20%, Mg: 2.5-3.0%, Cr: ≤0.20%, Zn: 10.0-11.5%, Ti: 0.03%, Zr: 0.15-0.30%, with individual impurities ≤0.05%, total impurities ≤0.10%, and the balance being Al. By optimizing the content of elements (Mn, Cr, Zr), optimizing the suppression of surface recrystallization thickness, strictly controlling the extrusion process and extrusion die exit temperature to reduce surface parameters and stress levels, and further eliminating residual stress through multi-stage gradient heating solution treatment, a comprehensive control method is used to achieve a coarse grain layer thickness of <0.2mm with complete surface recrystallization.
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Citation Information

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