Impact of Cold Rolling Deformation on the Microstructure and Mechanical Characteristics of Spray-Formed Al–Zn–Mg–Cu Alloy

Abstract

The effect of cold rolling deformation on the microstructure and mechanical properties of the spray- formed and extruded Al–9.8Zn–2.3Mg–1.7Cu alloy is investigated using various analysis methods, including electron backscatter diffraction (EBSD), tensile testing, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Two test schemes (heat treatment and deformation) were developed. According to the first scheme (SCA, solution treatment + cold rolling + aging), the material was treated at 480°C for 90 min, then quenched with water at room temperature, after which it was subjected to 10% cold rolling deformation and aged at 120°C for 24 h. The second scheme (SA, solution treatment + aging) involved treating the samples with a solution and aging at the same parameters as in the first group. The outcomes specified that compared to the solution-aging treated samples, the percentage of sub-grain in the cold rolling deformation treated samples increased from 33% to 66%. At the same time, the typical grain size reduced from 4.67 μm to 4.37 μm. The precipitate are more dispersed in the cold rolling deformation-treated samples. The dispersed deposits restrict the dislocation movement and promote the consistency of dislocation dispersal. Furthermore, the mechanical characteristics of the alloy are significantly boosted by the cold rolling deformation. Compared to the solution and aging procedure, the cold rolling deformation increases the tensile strength, yield strength, and sample elongation to new highs, from 655 MPa, 617 MPa, and 12.8% to 709 MPa, 683 MPa, and 13.2%, respectively. Fine-grain, precipitation, and dislocation strengthening are the primary strengthening mechanisms in the alloy.