This paper reports a new structured prismatic platelet, self-assembled by an ellipse-like quasi-unit cell, precipitated in Mg–In–Yb and Mg–In–Ca ternary alloys and aged isothermally at 200°C using aberration-corrected high-angle annular dark-field scanning transmission electron microscopy combined with density functional theory computations. The ordered stacking of solute atoms along the [0001]_α direction based on elliptically shaped self-adapted clustering leads to the generation of the quasi-unit cell. The bonding of these ellipse-like quasi-unit-cell rods by the Mg atomic columns along the 〈11{\overline 2}0〉_α directions formed a two-dimensional planar structure, which has three variants with a {10{\overline 1}0}_α habit plane and full coherence with the α-Mg matrix. This finding is important for understanding the clustering and stacking behaviors of solute atoms in condensed matter, and is expected to guide the future design of novel high-strength Mg alloys strengthened by such high-density prismatic platelets.

Zn–0.2Mg–0.8Mn alloys extruded at 300 and 150°C exhibited similar grain size, second phases, but different textures which were basal and non-basal texture, respectively. The initial textures affected the yielding and strain hardening stages. Non-basal texture was not conducive to the slipping of dislocations, causing high yield strength of 378 MPa but low strain hardening rate. Average grain size decreased from 2.2 ∼ 2.3 μm to 0.7 ∼ 0.8 μm by the formation of low angle grain boundaries. Deformation texture with $<\overline{1}2\overline{1}0>||\text{CD}$ (CD: compressive direction) was introduced by deformation. Dynamic recrystallisation (DRX) occurred as strain exceeded 0.16 and caused softening for both of the alloys. The DRXed grains exhibited average size of 0.7 ∼ 0.8 μm and texture with 〈0001〉 deviating 15° ∼ 30° away from CD.

Ti48Al2Cr2Nb alloy was prepared by selective laser melting (SLM). The effects of different rotational speeds on the friction properties of Ti48Al2Cr2Nb alloy and the alloy after hot isostatic pressing...