Interpretation of precipitation crystallography of Mg17Al12 in a Mg-Al alloy in terms of singular interfacial structure

Abstract

This work applies a constrained coincidence site lattice/constrained complete pattern shift lattice (CCSL/ CDSCL) model and secondary O-lattice model to simulate the interfacial structure in the major side interface of Mg 17 Al 12 /Mg. The result shows that, at the orientation relationship (OR) with a small deviation (ϳ0.5 deg) from the Burgers OR, the secondary misfit in the interface normal to the parallel ⌬g vectors can be completely accommodated by the steps. The secondary dislocation networks in the habit plane and major side facet have been calculated.

Microstructural evolution of cast Mg–Al–Zn during friction stir processing and subsequent aging

“…ð0 0 0 1Þ Mg k ð1 1 1Þ Mg 17 Al 12 and ½1 2 1 0 Mg k½1 1 2 Mg 17 Al 12 , ð0 2 1 1Þ Mg k ð1 1 0Þ Mg 17 Al 12 and ½1 0 1 0 Mg k½1 1 0 Mg 17 Al 12 were also reported by other investigators [57,62,65]. The near Burgers OR has been confirmed by Duly and other investigators [65,66]. Fig.…”

Precipitation and Hardening in Magnesium Alloys

“…[28,29,31] Despite the irrational orientation of these side facets with respect to both precipitate and matrix lattices, the major and minor side facets (Figure 2 respectively. Figure 2(a) shows the major side facet of a thin b plate that is embedded in the matrix phase.…”

“…[48] The structure of this metastable Mg 4 Zn 7 phase is identical to that of the equilibrium Mg 4 Zn 7 phase (space group B/2m, a = 2.596 nm, b = 1.428 nm, c = 0.524 nm, c = 102.5 deg) in the Mg-Zn system [49,50] rather than the triclinic structure (a = 1.724 nm, b = 1.445 nm, c = 0.520 nm, a = 96 deg, b = 89 deg, c = 138 deg) assumed for the Mg 2 Zn 3 phase by Gallot and Graf [51] and adopted by the others. [6,8,31] Even though it is still unclear whether the monoclinic phase Mg 4 Zn 7 is actually identical to the Mg 2 Zn 3 phase, it is commonly accepted [52] that these two phases are the same, as only one intermetallic phase exists at compositions close to Mg-(60-63.6) at. pct Zn in the Mg-Zn binary phase diagram.…”

Studies of Orientations of β″ Precipitates in Al-Mg-Si-(Cu) Alloys by Electron Diffraction and Transition Matrix Analysis

“…Over the years, the transition matrix has been extended to research quantitatively the crystallography theory, phase transformation, and diffraction patterns analyses of precipitates. [35,36] It was first applied to the martensitic transformation in 1948. [37] The detailed descriptions about the transition matrix can be found elsewhere.…”