A new strategy to simultaneous increase in the strength and ductility of AA2024 alloy via accumulative roll bonding (ARB)

作者：Naseri M; Reihanian M; Borhani E^*

来源：Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2016, 656: 12-20.

DOI：10.1016/j.msea.2016.01.020

• Accumulative roll bonding (ARB)
• Bimodal grain structure
• Electron backscatter diffraction (EBSD)
• Crystallographic texture
• Mechanical characterization

Nano/ultrafine grained (NG/UFG) AA2024 alloy produced by accumulative roll bonding (ARB) showed high strength (420 MPa) and very limited elongation (about 1.3%). A new strategy via ARB was developed to improve elongation (about 10%) of AA2024 alloy with a relatively high strength (365 MPa). The present strategy produced a bimodal structure consisting of coarse and ultrafine elongated grains in comparison to the UFG alloy. Electron backscattered diffraction (EBSD) revealed that after 4 ARB cycles, the fraction of high angle grain boundaries and mean misorientation angle of the boundaries in the bimodal grain structure were 61% and 2734, respectively, in comparison to that of annealed (54% and 24.96) and UFG (79% and 34.27) alloy. The crystallographic texture results indicated that, unlike the annealed AA2024 alloy, the intensity of Brass {011} < 211 > and S {123} < 634 > components remarkably increased in the UFG and bimodal alloy. Scanning electron microscopy (SEM) observations demonstrated that failure mode in bimodal alloy was ductile fracture with a combination of deep and shallow dimples.

• 出版日期2016-2-22