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The texture evolution mechanism of Mg-13.1Gd-3.9Y–2Zn-0.4Zr (wt%) alloys during reciprocating upsetting extrusion (RUE) and subsequent heat treatment were investigated in this study. The relationship between texture weakening and deformation mechanism during multi-pass deformation was further discussed. The results show that the strong (0001)∥ED basal texture was formed after RUE, which decreases with the increase of deformation passes; the texture type had no obvious change after T5 treatment, and the texture intensity decreases significantly after T6 treatment. The high proportion of deformed grains determines the formation of strong basal texture after a single pass deformation. Due to the strong anisotropy of LPSO phases, deformed grains with different initial orientations participate in deformation through kinking or activation of basal slip and prismatic slip, respectively, and have different effects on the final texture components. With the strain increases (2 P), the deformed grains are consumed by DRXed grains with random texture, and the non-basal slip of DRXed grains became the main deformation mechanism. After T6 heat treatment, the < 11 2 ̅ 0 > fiber texture components were formed in the sample, which is due to the random nucleation and preferential growth of recrystallized grain during solution treatment. The mechanical properties of the alloys are significantly improved after RUE deformation, but the improvement on ED is better than that on TD. The mechanical properties of the alloys are improved by T5 or T6 heat treatment. The anisotropy of the former is still maintained, while that of the latter is basically eliminated. • In this paper, the texture evolution mechanism of rare-earth magnesium alloys containing LPSO phases during deformation and its texture stability during subsequent heat treatment were investigated based on RUE severe plastic deformation.The relationship between texture weakening and deformation mechanism during multi-pass deformation is further explored. • The results show that the deformed grains with different initial orientations participate in the deformation through kinks and the activation of multi-slip system under the influence of the strongly anisotropic LPSO phases, and then they have different effects on the final texture components. • The DRXed grains consume the deformed grains through the DDRX and CDRX mechanisms under low and high strain, respectively, and gradually dominate the texture type with the increase of the cumulative strain. However, the orientation of DRXed grains is still very similar to the orientation of deformed grains after extrusion, reflecting a certain genetic effect. • As for the texture transformation of the alloy after subsequent heat treatment, the results show that T5 hardly changes the texture strength and type of the alloy, while the alloy after T6 treatment has a preferred orientation due to the occurrence of static recrystallization. • The mechanical properties of the alloys are significantly improved after RUE deformation, but the improvement on ED is better than that on TD. After T5 or T6 heat treatment, the mechanical properties of the alloys are further improved, the former still retains the anisotropy after deformation, and the anisotropy of the latter is almost eliminated. [ABSTRACT FROM AUTHOR]

The Mg–Gd–Y–Zn–Zr alloy containing a long period stacking ordered (LPSO) phase was subjected to multi-pass deformation by means of a multi-directional forging process, and the microstructure evolution and the influence of the LPSO phase on its dynamic recrystallization (DRX) were studied. The results showed that multi-directional forging can effectively refine the grain with the DRX fraction increased, and DRXed grains lead to the decrease of the texture intensity, which can significantly improve the mechanical properties of the alloy. The different morphologies of the LPSO phase have different degrees of promotion relative to DRX behavior. The lamellar LPSO phase with kinks promoted dislocation plugging, where there could be a potential nucleation site for DRX grains. The fragmented lamellar LPSO phase promoted the DRX process through the particle-stimulated nucleation mechanism, and the block-shaped phase was more prone to stress concentration, which promoted DRX. These effects resulted in continuous grain refinement and a more uniform microstructure. [ABSTRACT FROM AUTHOR]

The decreasing temperature reciprocating upsetting-extrusion (RUE) deformation experiment was carried out on Mg-Gd-Y-Zr alloy to study RUE deformation on the influence of microstructure of the alloy. This work showed that with the gradual increase of RUE deformation passes, the continuous dynamic recrystallization (CDRX) process and the discontinuous dynamic recrystallization (DDRX) process occurred at the same time, and the grain refinement effect was obvious. Particulate precipitation induced the generation of DRX through particle-stimulated nucleation (PSN). In addition, after one pass of RUE deformation, the alloy produced a strong basal texture. As the RUE experiment proceeded, the basal texture intensity decreased. The weakening of the texture was due to the combined effect of DRX and alternating loading forces in the axial and radial directions. After four RUE passes, the mechanical properties of the alloy had been significantly improved, which was the result of the combined effect of dislocation strengthening, fine grain strengthening, and second phase strengthening. [ABSTRACT FROM AUTHOR]