Simultaneously enhanced strength and corrosion resistance of Mg–3Al–1Zn alloy sheets with nano-grained surface layer produced by sliding friction treatment

Formation of gradient microstructure and mechanical properties of hot-pressed W-20 wt% Cu composites after sliding friction severe deformation

“…It can be concluded that W particles have been refined after the SFD process. Similar phenomenon has been observed in Mg alloys by Huo et al[22], who reported that an average grain size of 70 nm on the topmost surface was obtained after 100 cycle repeated sliding friction treatment.On the other hand, EDS mapping results shown inFig. 4(e) and 4(f) demonstrate the inhomogeneous deformation of W skeleton during the SFD.…”

“…a) The designed set-up for SFD process; (b) ~ (e) an illustration of the step-by-step SFD processes[22]. Observing location of the texture testing.…”

Strength and Ductility with Dual Grain-Size and Texture Gradients in AZ31 Mg Alloy

“…The SRR-treated AZ31 sheets show an increase in strength with a little sacrifice of ductility, as shown in Figure 2 Figure 2(a), which shows a hump feature at P = 160 N, 200, and 240 N that deviates from the conventional linear strength-ductility variation in either uniform or gradient grain-size materials. [22,26,28,[31][32][33][34] To understand the hump feature in Figure 2(a), we further characterized the variation of the cross-sectional hardness, the depth of the hardened layer, and the microstructures along the depth for different vertical loads. The cross-sectional hardness of SRR-treated samples exhibits a gradient variation, as plotted in Figure 2(b) as a function of the depth from the surface, according to which, we determined the depth of the hardened layer.…”

“…The continuous rings in the corresponding selected area electron diffraction (SAED) patterns (the inset) indicate that the orientations of these nanocrystals are nearly randomly distributed. The transversal grain-size distribution of the layer about 10 lm beneath the surface is presented in Figure 4(j) with an average size of 117 nm, a typical size that can be achieved in surface mechanical treatment of AZ31 sheet with various techniques, such as SMAT, [25,29] sliding friction treatment, [31] and wire-brushing. [23] As the depth of grain-refined layer is much smaller than that of the hardened layer (the latter reaches almost to the most center when P ‡ 200 N), it is needed to reach beneath the grain-refined layer and check the other microstructural aspects such as degree of deformation and texture variations.…”

“…[28] In our experiment, we modified grain size and texture in the surface layer of AZ31 sheets on both sides by surface rotation rolling (SRR) technique. Compared with SMAT [25,29] and other similar surface treatments, [23,30,31] SRR treatment can be utilized for large plates and result in fine surface finishing. By changing vertical loads, we tailored the microstructure with gradients in grain size and basal texture contents, and conducted tensile testing of SRR-treated samples.…”