Achieving ultra-strong Magnesium–lithium alloys by low-strain rotary swaging

Nano-Gradient Materials Prepared by Rotary Swaging

“…Moreover, the residual stress also has an effect on strength. References [43] point out that the strength dis- Interestingly, according to previous literature, there are three different hardness/strength distributions observed in the cross sections (top view) of RSed rods: (1) V-shaped distribution [40,43]-the strength of edge is higher than that of the center; (2) uniform distribution [64]-the strength of edge is basically equal to that of the center; (3) Λshaped [41,50,65]-the strength of edge is lower than that of the center. Fortunately, these hardness distributions are detected in the Cu rods with various strains.…”

“…Currently, RS technology is not only used for manufacturing hollow/solid cylindrical shafts, difficult to deform materials and less plastic metals (e.g., tungsten and magnesium alloys), but also for the fabrication of the hollow/solid shafts with variable diameter and of the workpieces with various cross-sections via proper die design [45][46][47]. In addition, because of the significant strengthening effect with low strain [40] and excellent grain refinement ability [48], RS is employed to fabricate the workpieces with ultrafine-grained (UFG) structure or even NG structure. Recently, RS processed materials were reported to exhibit excellent mechanical [40,41,[49][50][51][52][53], fatigue [54][55][56], corrosion [57][58][59][60], tribological [61], electrical properties [61][62][63], etc.…”

“…In addition, because of the significant strengthening effect with low strain [40] and excellent grain refinement ability [48], RS is employed to fabricate the workpieces with ultrafine-grained (UFG) structure or even NG structure. Recently, RS processed materials were reported to exhibit excellent mechanical [40,41,[49][50][51][52][53], fatigue [54][55][56], corrosion [57][58][59][60], tribological [61], electrical properties [61][62][63], etc. We will discuss them in detail in Section 3.…”

“…Additionally, compared with the edge (Figure 5b-2), the center has a higher density of dislocations (Figure 5c-2) i.e., a dislocation density-gradient. Hence, the authors consider the high Recently, RS processed materials were reported to exhibit excellent mechanical [40,41,[49][50][51][52][53], fatigue [54][55][56], corrosion [57][58][59][60], tribological [61], electrical properties [61][62][63], etc. We will discuss them in detail in Section 3.…”

“…A distinct V-shaped hardness distribution appears in the top view of RSed Mg-4Li-3Al-3Zn alloy (Figure 11b). Later on, Yang et al employed a low-strain RS to fabricate a bulk ultra-light Mg-4Li-3Al-3Zn alloy with new strength record (405 MPa, Figure 10a) [40]. The enhanced mechanical strength is primarily attributable to three reasons: (1) high density of deformation twins; (2) high density of stacking faults; (3) high density of basal <a> and pyramidal <c+a> dislocations.…”