Microstructure and properties of the Zn–1%Li–2%Mg alloy subjected to severe plastic deformation

In this paper, the authors consider mechanisms of formation high-strength states in Zn–1%Li–2%Mg alloy as a result its processing by high pressure torsion (HPT) method. For first time, study showed that using HPT treatment, varying degree deformation at room temperature, it is possible to increase ultimate strength zinc from 155 383 MPa (with an yield stress 149 306 MPa) without losing ductility. To explain reasons for mechanical properties, microstructure was analyzed scanning electron microscopy (SEM), X-ray phase analysis (XPA), diffraction (XRD), and small-angle scattering (SAXS). Using XPA, established time Zn(eutectic)+β-LiZn4(eutectic)→~LiZn3+Zn(phase)+Zn(precipitation) MgZn2→Mg2Zn11 transformations occur during treatment. SEM initial stages cylindrical Zn particles with diameter 330 nm length up 950 precipitate β-LiZn3 phase. At same SAXS method needle-like LiZn4 9 28 The that, only spherical degrees Precision treatment leads grain refinement, magnitude crystal lattice microdistortion, growth density dislocations, which are predominantly edge type. As hardening mechanisms, concluded characteristics mainly occurs due grain-boundary, dislocation, dispersion hardening.