Precipitation in Mg-(4-13)%Li-(4-5)%Zn Ternary Alloys

Abstract

Precipitations in Mg-Li-Zn ternary alloys containing 4 to 13%Li and 4 to 5%Zn (in mass%) with or single phase, or with ( þ ) dual phases were investigated using a micro-Vickers hardness measurement and transmission electron microscopy. Age hardening in the phase alloy was found to occur, which was attributed to the precipitation of the stable (MgLiZn) phase with the following orientation relationships: ½10 1 10 k ½110 , ð0001Þ k ð1 1 1 1 1Þ . In the ( þ ) phases alloy, the precipitation of the phase together with the metastable 0 (MgLi 2 Zn) phase occurred at grain boundaries between the and , and also and grains. The orientation relationships between the and 0 were as follows; ð0001Þ k ð01 1 1Þ 0 , ½0 1 110 k ½111 0 . Age hardening in the alloy was caused by the precipitation of the 0 phase and over-aging was attributed to the precipitation of the and phases.

A Study of Aging Treatment on the Mg-10Li-0.5Zn Alloy

“…Recently, some articles have studied the mechanical properties of MgLi alloys, including the effects of cold working, addition of alloying elements and precipitation hardening. [7][8][9][10] Hsu et al have also investigated the natural aging of Mg-Li-Al-Zn alloy.…”

Strengthening in dual-phase structured Mg-Li-Zn alloys

“…2). They might be the Widmanstätten type precipitates precipitating in solid β-phase due to the drop in Mg solubility on the cooling [8]. Volume fractions of primary α-phase (without precipitates of secondary α-phase) in alloys A, B, and C as determined by the linear intercept method are presented in Table 1.…”

Effect of Friction Stir Processing on the Microstructural Evolution and Tensile Behaviors of an α/β Dual-Phase Mg–Li–Al–Zn Alloy

“…Moreover, another new phase is detected, which is recognized as a precipitation of the metastable ª-phase (a MgLi 2 Al compound) reported in the literatures. 11,28) The appearance of the AlLi peak (see Fig. 4(a) cf.…”

“…The reduction in strengthening effect for the LAZ931-FSP/A should be related to the phase transformation from the metastable ª-MgLi 2 Al into the equilibrium AlLi compound. 28,36) In addition, the coarsening of precipitated ¡-phase at ¢-phase grain boundaries is also harmful to the tensile strength because the decohesioninduced cracks propagation is occurred at the weak ¡/¢-phase interface boundaries. 37) The interfacial cracking will further reduces the elongation of friction stirred specimens.…”