Microstructure and Corrosion Properties of Duplex-Structured Extruded Mg-6Li-4Zn-xMn Alloys

Abstract

The extruded Mg-6Li-4Zn-xMn (x = 0, 0.4, 0.8, 1.2 wt%) alloys were prepared, and the microstructure of the test alloys was investigated by optical microscopy, scanning electron microscopy and transmission electron microscopy. The corrosion properties were determined by electrochemical measurements and immersion measurements in 3.5% NaCl solution. The results indicate that the extruded Mg-6Li-4Zn-xMn alloys are mainly composed of α-Mg phase, β-Li phase, Mn precipitates and some intermetallic compounds (MgLi 2 Zn). With the addition of Mn, stable corrosion products were formed on the surface of the test alloy, which can effectively inhibit further corrosion progress and improve the corrosion resistance. Mg-6Li-4Zn-1.2Mn alloy exhibits the best corrosion resistance, attributed to grain refinement, the improvement of the stability of corrosion product film and uniform distribution of fine second phases.

Deformation Behavior and Microstructure Evolution of AZ31 Mg Alloy by Forging–Bending Repeated Deformation with Multi-pass Lowered Temperature

“…3.2, this may explain aforementioned the texture result in Fig. 8, which non-basal slips activates more frequently, especially, pyramidal < c + a > slip, providing 5 independent slip directions, including c dislocation that can coordinate deformation with a dislocation, which not only make the grain size decrease, but also trigger CDRX and DDRX to enhance the anisotropy of microsturcture [9,22]. Furthermore, all SF distributions of 4 passes extend in two opposite directions in TD.…”

“…These LAGBs could become HAGBs with increased strain, eventually converting substructured grains into brandnew DRXed grains. A typical continuous dynamic recrystallization (CDRX) mechanism is like these [9,20,41].…”

“…Different degrees of dilatation took place at the grain boundaries of the parent grains, and the current grain boundaries bulged toward the nearby grains. New fine DRXed grains formed and grew along the triple junctions and the serrated grain boundaries of the parent grains, which is a typical discontinuous dynamic recrystallization (DDRX) one [9,20,41]. Hexagonal prisms were used to indicate the parent grain's and the nearby DDRX grains' respective crystal orientations.…”

“…Grain refinement is one of the most effective approaches to improving the strength and flexibility of materials in a synergistic fashion [9,10]. One of the most important methods of that has been confirmed to be severe plastic deformation (SPD) [11][12][13].…”

The Corrosion Behaviors of an As-Rolled Mg-8Li (in wt.%) Alloy in Two Differently Concentrated NaCl Solutions

“…Accordingly, it can be concluded that the corrosion behavior of Mg alloys in NaCl solutions depends on the Cl − concentration and the microstructural characteristics. For Mg-Li based alloys, although their corrosion behaviors in NaCl solutions have been widely reported [22][23][24][25][26][27], no related work about the effect of Cl − concentrations on the corrosion behavior of Mg-Li alloys has been performed.…”