Significant anisotropy in mechanical properties was observed in 316L stainless steel (SS) that was subjected to selective laser melting (SLM) to produce a hierarchical structure, composed of molten pool, columnar grains, and a cellular substructure. Such anisotropy was induced by the geometric relationship between the boundary of the molten pool and the tensile force. The in situ tensile test showed initial deformation rapidly occurred at the boundary of the molten pool, followed by strain localization, and a lower ductility was obtained when loaded in the longitudinal direction (perpendicular to the molten pool). By contrast, the deformation was significantly constrained because of the geometry of the boundary of the molten pool, and substantial deformation occurred in the cellular substructure during loading in transverse direction (parallel to the molten pool). Finally, the quantitative analysis revealed that the high-level strength was attributed to the high-density dislocations and the fine cellular substructure.

The microstructure evolution, texture, mechanical behavior and twin deformation of the ECAPed Mg–2Y–0.6Nd–0.6Zr alloy at room and liquid nitrogen temperature were investigated by rolling samples. The ECAP processed material appeared the texture of 45° to the extrusion direction and its yield strength reached 93.6 MPa. The results showed that cryorolling encourages twinning in Mg–2Y–0.6Nd–0.6Zr alloy, enhancing the tensile strength and texture. Activation of {10–12} twinning during rolling was found to be more pronounced in the cryorolled samples than in the cold rolled samples owing to a lower temperature. As a result, the cryorolled samples had more twins than and cold rolled ones, the proportion of twin areas of room temperature rolling and ultra-low temperature rolling were: 2.45% and 4.23%.

In this work, as-cast rare earth Mg-2Y-0.6Nd-0.5Zr alloy was successfully processed by forging at 350 °C and different numbers of passes of equal channel angular pressing (ECAP) along the Bc route. The effects of ECAP on the microstructure, texture and mechanical properties of a pre-forged Mg-2Y-0.6Nd-0.5Zr alloy were systematically investigated in this paper. The grain size of the alloy was refined from 140 μm to 1.9 μm by forging + ECAP. The alloy has obtained a uniform and fine microstructure under the action of dynamic recrystallization (DRX) during the ECAP process. The forged sample exhibited a strong basal texture. However, the alloy that was processed with ECAP had a tilted texture; the basal orientation was weakened, and the cylindrical and pyramidal orientation was enhanced. An analysis of the mechanical properties showed that the alloy exhibited favorable tensile strength and elongation of 262 MPa and 22.4% after forging and 4 passes of ECAP, which were increased by 118% and 113% compared with the as-cast sample. The alloy strength decreased slightly due to textural transformation and a high degree of recrystallization during ECAP, while the plasticity of the alloy that underwent 6 ECAP passes increased to 25.2%. The results show that the combination processing of forging and ECAP provides a new approach for optimizing the mechanical properties of magnesium alloys.