Jiejun He

Octahedral cuprous oxide synthesized by hydrothermal method in ethanolamine/distilled water mixed solution

Octahedral cuprous oxide has been synthesized by a simple hydrothermal method using copper sulphate and sodium hydroxide as raw materials in ethanol amine/distilled water mixed solution. The synthesized cuprous oxide powders were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy. XRD pattern exhibited that the nanocrystalline nature with cubic structure for the synthesized nanostructures. Analysis results reveal that pH value of solution plays an important role in the formation of octahedron shape for cuprous oxide. A probable formation mechanism of octahedral cuprous oxide is also proposed.

Effect of aluminium on the microstructure and mechanical properties of as-cast magnesium–manganese alloys

ABSTRACT In this paper, the effect of aluminium on microstructure and mechanical properties of as-cast magnesium–manganese alloy has been investigated by means of X-ray diffraction, optical microscopy and scanning electron microscopy. The results reveal that various Al–Mn intermetallic compounds form with an increase of Al content. As a result, microstructure of AM11 alloy has been effectively refined due to the formation of Al8Mn5 phase along the grain boundary, while Al addition is explained as the main reason on refining the microstructure of AM91 alloy due to its higher grain growth restriction factor value of ∼4.32. The tensile yield strength (TYS) has been improved steadily from 27.4 to 122.9 MPa with increasing Al content, because of the combined effects of grain boundary strengthening, solid solution strengthening and precipitation hardening behaviours.