Effect of pre-stretching and aging time on the mechanical properties and microstructure of Al-6.02Zn-1.94Mg alloy. (December 2021)

• Record Type: Journal Article
• Authors: Nie, Changchang; Huang, Yuanchun; Shao, Hongbang; Wen, Jinchuan
• Is Part Of: Vacuum. Volume 194(2021)
• Publication Date: 2021-12
• Subjects: Mechanical properties -- Microstructures -- Fracture morphology -- Al–Zn–Mg alloy; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2021.110553
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: 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. Highlights: 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.