The influence of high-pressure torsion (HPT) processing on the texture and microhardness of two binary Mg-RE (RE=Nd and Ce) alloys was investigated using X-ray diffraction and Vickers microhardness measurements. Disks cut from the alloys were processed by HPT at room temperature for up to 10 turns. The precipitation products of both alloys were identified using synchrotron radiation. The results show that both alloys exhibit a weak basal texture where the c-axis of most grains is shifted 15° from the shear direction. An Mg-1.44Ce (wt. %) alloy showed a continuous decrease in the texture strength which may be due to the effect of second precipitation phases (Mg 17 Ce 2 and MgCe 2). The microhardness of both alloys increased significantly with increasing HPT turns but levelled-off beyond about one HPT turn. Maximum values of ~65 and ~96 Hv were achieved which are significantly higher than the hardness of the undeformed Mg-Ce and Mg-Nd alloys.

The sequence and kinetics of pre-precipitation in an Mg-1.43Nd (wt.%) alloy was investigated after severe plastic deformation by high-pressure torsion (HPT) at room temperature using in situ synchrotron X-ray diffraction and differential scanning calorimetry (DSC). In situ aging at 250°C up to 5 h led to precipitation of the β 1-Mg 3 Nd and β-Mg 12 Nd phases but without any evidence for the metastable β ''' (undifferentiated β ''-DO19 and β'-Mg 7 Nd) or equilibrium β e-Mg 41 Nd 5 phases. The β 1-Mg 3 Nd and β-Mg 12 Nd phases appeared rapidly after HPT processing and their amounts were relatively large compared to the nondeformed sample. The Avrami time exponent of the β-Mg 12 Nd phase had a value near unity indicating a mechanism of nucleation after saturation and growth of the particles in 2 dimensions. DSC analysis revealed all metastable phases as well as the equilibrium phase. The activation energies associated with the pre-precipitation phases ranged between ~126 and ~235 kJ mol-1 .

The texture, microstructure, and mechanical properties of Mg-1.33La (wt.%) alloy after hot rolling and cold plane strain compression were investigated by using X-ray diffraction, optical microscopy, and micro-hardness measurements. This thermo-mechanical processing resulted in a relative weakening of the texture that was mainly a basal type. The microstructures after hot rolling and cold plane strain compression revealed the presence of a second phase (Mg17La2), mostly at grain boundaries. Twins were profuse, and their morphologies were quite different after hot rolling and cold plane strain compression. The Mg-1.33La (wt.%) alloy exhibited good room temperature formability and an increase in strength. The alloy's hardness increased with increasing deformation strain. Such properties were explained by the effect of both the Mg17La2 phase precipitation and the sample's texture.