Microstructure and Mechanical Properties of Magnesium Alloy AZ31 Processed by Compound Channel Extrusion

Abstract

We report microstructure evolution and mechanical properties of Mg alloy AZ31 processed by a new severe plastic deformation technique which combines forward extrusion, equal channel angular extrusion (ECAE) and change channel angular extrusion (CCAE). Under all of the processing temperatures ranging from 623 K to 723 K, the grain size of the as-extruded sample was remarkably refined, which is attributed to the grain subdivision and dynamic recrystallization during the drastic deformation. We have also found the strength and tension-compression asymmetry were improved. Simultaneously, micro-fracture of tensile exhibited the characteristics of ductility, indicating plasticity of Mg alloy AZ31 was improved by compound channel extrusion.

Nanoindentation study of MAO coatings developed by dual electrolytes

“…It is interesting to note that the typical hardness data reported for the base AZ31 Mg alloy is about 0·73–0·78 GPa. 24,25 These data matched favourably with those measured in the present work for the base AZ31 Mg alloy. Further, the nanohardness data measured in the present work matched favourably with those reported for other MAO coatings.…”

“…26,27 Clearly, depending on the processing technique, the hardness of MgO has been reported to be about five times to an order of magnitude higher than that of the AZ31 Mg alloy. 24,25 These facts 26,27 can certainly rationalise the present data (Fig. 4 c – f ) which showed that the MAO coatings had H and E values as high as about 3–7 times and 1·5–2·5 times those of the as received AZ31 Mg alloy respectively.…”

“…24,25 These data matched favourably with those measured in the present work for the base AZ31 Mg alloy. Further, the nanohardness data measured in the present work matched favourably with those reported for other MAO coatings.…”

“…MgO, MgO.SiO 2 , Mg 2 P 2 O 7 and MgF 2 phases possessed better hardness than the base AZ31 Mg alloy phase. [24][25][26][27][28][29][30][31] Consequently, by virtue of the simple composite concept, the higher nanomechanical properties were expected in the current MAO coatings as were also experimentally observed (Fig. 4).…”

Effect of immersion time on the electrochemical behaviour of AZ31B alloy

“…1, the strongest XRD diffraction peak of AZ31B alloy is (0002). This peak is also found the strongest XRD diffraction peak of AZ31 alloy [25]. Fig.…”