Effect of pre-stretching and aging time on the mechanical properties and microstructure of Al-6.02Zn-1.94Mg alloy

• Published in: Vacuum Vol. 194; p. 110553
• Main Authors: Nie, Changchang, Huang, Yuanchun, Shao, Hongbang, Wen, Jinchuan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2021
• Subjects: Al–Zn–Mg alloy; Fracture morphology; Mechanical properties; Microstructures; Fracture morphology; Al–Zn–Mg alloy; Mechanical properties; Microstructures
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2021.110553

The mechanical properties and microstructures of the Al-6.02 wt% Zn-1.94 wt% Mg alloy were researched by tensile test, hardness test, optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The results showed that the peak aging time shortens and the tensile strength slightly enlarges with the increase of pre-stretching. Synchronously, the cleavage fracture of the pre-stretched samples from 0% to 6% was increasingly apparent, and their elongation got lower. The precipitation sequence of 4% pre-stretched alloy during aging treatment at 120 °C was supersaturated solid solution (SSS) → GPI zone → η′ phase → η (MgZn2) phase. Rationally, the under-aged GPI zone and the over-aged η phase had smaller contribution to the intensity as against the η′ phase of the peak-aged state. The GPI zone was beneficial to elongation, which improved the fracture morphology. •The peak aging time of Al–Zn–Mg alloy shortens with increasing pre-stretching.•After the pre-deformation treatment, the tensile strength was subtly improved.•As pre-stretching increases, cleavage fractures become more evident.•For the underaged Al–Zn–Mg alloy, the strain hardening exponent decreases.