In present paper, Al element was introduced to weaken the basal texture of Mg-8Gd-5Y-2Zn alloy. Due to the addition of Al, the precipitation of Mg12Zn(Y, Gd) is significantly depressed, while the precipitation of Mg3Zn3(Y, Gd)2, Al11(Y, Gd)3, and Al2(Y, Gd) is enhanced. The Al11(Y, Gd)3 and Al2(Y, Gd), which are located in grain interior, stimulate the dynamic recrystallization due to the particle-stimulated nucleation (PSN) effect in cross-rolling process. This results in a multi-peak characteristic with wider orientation distribution of basal poles. Furthermore, the maximum pole intensity of the as-rolled Mg-8Gd-5Y-2Zn-1Al alloy was significantly weakened.

A kind of new Mg–Mg2Sn composite was developed successfully. The Mg2Sn reinforcement was synthesized effectively by milling micro-sized Mg and nano-sized Sn powders. The effect of milling on formation of Mg2Sn phase from elements powders was investigated. The microstructures and mechanical properties of the composite were presented. The results showed that, high surface activation of raw nano-sized Sn powder would be greatly beneficial to accelerate transformation efficiency of Mg2Sn nanophase from Mg–Sn mixture. After sintering, Mg2Sn cluster consisting of Mg2Sn nanophase was uniformly distributed in the matrix. The Mg–Mg2Sn composite exhibited an appreciable benefit in terms of hardness and compressive strength, while ductility remained quite high.

•Effect of Al on microstructure, texture and mechanical properties of the as-rolled Mg-Gd-Y-Zn alloys was firstly discussed.•The addition of Al significantly affected the solidification and precipitation behaviour of the Mg-5Gd-2.5Y-2Zn alloy.•The addition of Al inhibited edge and surface cracks, and increased the rollability of the Mg-5Gd-2.5Y-2Zn alloy.•The elongation of Mg-5Gd-2.5Y-2Zn-1Al sheet was about 16.4% reaching about 4 times as high as the Mg-5Gd-2.5Y-2Zn alloy.In this paper, microstructure, texture and mechanical properties of as-rolled Mg-5Gd-2.5Y-2Zn-xAl (x = 0, 0.5, 1.0 and 1.5 wt%) alloys were investigated. It was found that the added Al changed the solidification and precipitation behaviour of the matrix alloy by the formation of the Al-RE (Al11(Y, Gd)3 and Al2(Y, Gd)) phases. Edge and surface cracks happened in the as-rolled Mg-5Gd-2.5Y-2Zn alloy disappeared after adding Al. Both the broken W phase and the two Al-RE particles can stimulate nucleation of dynamic recrystallization via particle stimulated nucleation (PSN) mechanism. The content, size and distribution of second phase particles were affinitive with the effect of PSN mechanism, and then affected the texture characteristics, such as intensity and orientation distribution. The elongation of the Mg-5Gd-2.5Y-2Zn alloy was pretty low, just about 4.4%. After the addition of Al, although there was a slight decrease in strength, the ductility was obviously increased. Especially, the elongation of the alloy with 1.0 wt% Al addition was about 16.4% which approached 4 times as high as the Mg-5Gd-2.5Y-2Zn alloy. Besides, Al addition significantly changed the fracture surface of the Mg-5Gd-2.5Y-2Zn alloy. In particular, as 1.0 wt% and 1.5 wt% Al was added, many deep dimples were clearly observed, which showed obvious ductile characteristics.

For the application of the Al–Ti–B system in Al-free Mg alloys, yttrium was selected and its effect on microstructure, texture and mechanical properties of Mg–6Zn/TiB2p composite was studied. The results indicate that the addition of Y could transform the extra Al (which is the by-product of the Al–Ti–B SHS reaction) into Al2Y and Al11Y3 phases, and then refined the as-homogenized microstructure of the Mg–6Zn/TiB2p composite. The Al2Y and Al11Y3 particles, as well as the TiB2 particles, effectively stimulate the occurrence of dynamic recrystallization during the cross-rolling, which contribute to the grain refinement and the formation of a weak double peak texture. That results in the comprehensive improvement of the mechanical properties.

TiB2/AZ31 magnesium matrix composites were prepared under the separate effects of an electromagnetic field, ultrasound and of both in combination. The electromagnetic field appeared to expand the zone of ultrasonic action, resulting in fine grained and more uniform microstructure with a more homogeneous distribution of the reinforcing TiB2 particle clusters in the magnesium alloy matrix. Subsequent hot-rolling further improved the microstructural homogeneity. The resulting TiB2/AZ31 composite sheets exhibited excellent overall mechanical properties, with an ultimate tensile strength of 350 MPa and a tensile ductility approaching 8%.

•Apart from 18R-LPSO, 14H-LPSO structure was determined in the MgNiY alloys.•The appearance of twin-related structure in 18R-LPSO structure results from the stacking faults in the stacking sequence of the closely packed planes.•A new (Pb, Mg)2Y phase with a body-centered orthorhombic structure was determined in the MgPbY alloy.•No LPSO structures were found in the MgPbY and MgTiY casting alloys.Formation of long-period stacking ordered (LPSO) structures is investigated in Mg88M5Y7 (M = Ti, Ni and Pb) casting alloys by means of electron microscopy and X-ray diffraction. In the Mg88Ni5Y7 casting alloy, 14H-LPSO structure is observed in a small amount, which coexists with 18R-LPSO structure. The appearance of stacking faults in 18R-LPSO structure results in twin-related structure in the stacking sequence of the closely packed planes. A new (Pb, Mg)2Y phase with a body-centered orthorhombic structure is determined in the Mg88Pb5Y7 alloy. No LPSO structures are found in the Mg88Pb5Y7 and Mg88Ti5Y7 casting alloys. In terms of the atomic radius and heat of mixing, the formation ability of LPSO structure in the present alloys is discussed.