Synergistic strengthening of crack-free Al–Zn–Mg–Cu alloys with hierarchical microstructures achieved via laser powder bed fusion

Figures & data

Figure 1. (a) EBSD inverse pole figure map of the as-built alloy. (b1) BSE image of the boundary between CG and EG regions. High-magnification BSE image of (b2) CG and (b3) EG regions. TEM-EDS results for (c) CG and (d) EG regions. SAED patterns in (c) and (d) correspond to the diffraction patterns of θ-Al₂Cu and L1₂-Al₃Zr, respectively. (e) Schematic of grain morphology and distribution of precipitates in the Al–Zn–Mg–Cu–Zr alloy. (f) Hardness measurement results at each region in as-built Al–Zn–Mg–Cu–Zr alloy.

Figure 2. Tensile test results of as-built Al–Zn–Mg–Cu–Zr alloy and other as-built Al alloys with inoculants [18,24,32].

Figure 3. (a) Micro digital image correlation results. (a1), (a2), and (a3) Local equivalent strain (ε_e) maps at the initial state and the global strains of 2% and 4%, respectively. (b) Line profile of ε_e from A₀ to A₂₀ along the white line in Figure 3(a3). (c) and (d) GNDs density maps of the initial state and at the global strains of 4%, respectively. (e) Schematic of the accumulation of GNDs at the interfaces.

Table 1. Average equivalent strains in each domain.

εg	εe in CG	εe in UEG	εe in MEG
2%	5.04 ± 0.24%	5.42 ± 0.32%	5.80 ± 0.67%
4%	6.14 ± 0.22%	6.86 ± 0.49%	7.00 ± 0.35%

Figure 4. Tensile test results for as-built Al–Zn–Mg–Cu–Zr alloy. (a) True strain–stress curve of the LUR test. (b) HDI stress and effective stress of Al–Zn–Mg–Cu–Zr and Al–Mg–Sc–Zr [18]. alloys, respectively. (c) YSs of Al–Mg–Sc–Zr [18] and Al–Zn–Mg–Cu–Zr alloys. (d) Ashby plot of as-built Al–Zn–Mg–Cu–Zr, Al–Zn–Mg–Cu–Sc–Zr [7], Al–Cu–Mg–Zr [24,38,39], Al–Mg–Sc–Zr [18,40], and Al–Mg–Zr alloys [32].

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