Giant hardening and formation of nanograined supersaturated solid solution in Al–Zn system

Figures & data

Figure 1. Characterizations of LNT-HPT processed UFG-320 (a–d) and NG-15 (e–k) samples: (a) IPF map and (b) the corresponding phase map, (c) The Zn elemental mapping and (d) line-scan of Zn concentration along the white arrow in (c). (e) A bright field TEM image and corresponding SAED pattern (inserted). (f) IPF map. (g) The Zn elemental mapping and (h) line-scan of Zn concentration along the white arrow in (g). (i–k) High resolution TEM image of GB structures in NG-15 sample.

Figure 2. (a) XRD patterns of the CG and as-deformed Al–21.7Zn alloy. (b) Variation of lattice parameter (upper stack) and volume fraction of Zn-rich phase (lower stack) with grain size in the as-deformed Al–21.7Zn alloy. Data collected from Al–15.1Zn alloy processed by means of severe plastic deformation are included for comparison [20].

Figure 3. Variation of (a) measured and (b) normalized Zn percentage inside α-Al grains as a function of grain size of the as-deformed Al–21.7 Zn alloy. Data collected from Al–Zn alloy with different Zn concentrations processed by means of severe plastic deformation are included for comparison (Al–4.4 Zn [20, 37], Al–9.4 Zn [20, 36], Al–15.1 Zn [20, 34, 37, 38, 48] and Al–30 Zn [35]).

Table 1. Parameters of microstructure in the cryogenic HPT deformed Al–Zn samples obtained by XRD spectrum analysis using TOPAS software.

Samples	dTEM (nm)	dXRD (nm)	Microstrain (%)	Dislocation density (m^−2)
UFG-320	320	223	0.0626	3.4$\times$10^13
NG-34	34	41	0.4668	1.38$\times$10^15
NG-15	15	20	0.5057	3.06$\times$10^15

Figure 4. (a) Engineering stress-strain curve of CG and as-deformed Al–21.7Zn alloy (as indicated). SEM image of CG (b1–b2), UFG-320 (c1–c2), NG-34 (d1–d2) and NG-15 (e1–e2) micropillar before and after compression, respectively (image tilt angle 52°). Scale bar, 5 μm.

Figure 5. Plot of yield strength as a function of the grain size of the nanostructures Al–21.7Zn alloy. Data collected from Al–Zn alloy with different Zn concentrations processed by means of severe plastic deformation are included for comparison (Al–4.4Zn [16], Al–9.4Zn [16, 36], Al–15.1Zn [16, 18, 22, 48, 51] and Al–30Zn [15]).

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