Investigation of the Deformation Characteristics and Mechanical Properties of Al-Zn-Mg-Cu Alloy Subjected to Pre-aged Hardening Forming

doi:10.3901/JME.2025.06.160

Abstract

Abstract: The traditional hot stamping technique for high-strength aluminum alloys initially forms the geometric structure and obtains the microstructure properties after heat treatment, which has a number of drawbacks, including heat treatment deformation, poor precision, a long process, and low efficiency. A quick, accurate, and effective hot stamping forming process without additional heat treatment is developed：pre-aged hardening forming. Taking 7075 aluminum alloy as the research object, the influence of process parameters on the thermal deformation behavior and formability of pre-aged aluminum alloy sheet is investigated by experiments of uniaxial thermal tensile test and Erichsen test. By using EBSD and TEM to analyze the evolution of microstructure during the process, the evolution law of mechanical properties and strengthening mechanism in the forming process PHF are revealed. The peak flow stress of pre-aged aluminum alloy sheet increases with the increase in treatment temperature and duration, according to the true stress-strain curve, and it shows obvious work hardening phenomena. Pre-aged aluminum alloy sheet has a greater Erichsen test value than O-state aluminum alloy under identical test conditions and is easier to shape, and diminishes as pre-aged temperature and time rise. The larger the deformation, the better the mechanical properties of the formed components will be enhanced. In PHF stamping, the superposition of phase transformation and deformation strengthening allows the produced component to acquire the necessary mechanical characteristics without additional heat treatment.

Key words: 7075 aluminum alloy, pre-aged hardening forming, influence of the process parameters, microstructure evolution

CLC Number:

TG306

HU Zhili, LU Junjie, WEI Pengfei, HUA Lin. Investigation of the Deformation Characteristics and Mechanical Properties of Al-Zn-Mg-Cu Alloy Subjected to Pre-aged Hardening Forming[J]. Journal of Mechanical Engineering, 2025, 61(6): 160-173.

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