An investigation into the capability of unconventional amount of aluminum and nano-alumina to alter the mechanical response of magnesium

In the present study, magnesium aluminum alloys with aluminum content exceeding conventional alloying limit (Mg–10Al, Mg–15Al, and Mg–20Al) and the composite of Mg–10Al alloy with 1.5 volume percentage of nano-alumina particulates are created using the technique of disintegrated melt deposition. Significant improvements in microstructure and mechanical properties compared with pure magnesium are obtained. Intermetallic phase Mg₁₇Al₁₂ was detected in all the materials. The increase in amount of aluminum in magnesium led to a reduction in coefficient of thermal expansion and a marginal increase in porosity. Yield strength, ultimate tensile strength, and hardness increased significantly with an increasing amount of aluminum. The 0.2% yield strength increased from 140 to 394 MPa (181%) in the case of Mg–20Al. Ductility reduced with progressive addition of aluminum. However, the addition of both Al and nano-alumina particulates significantly increased not only strengths, but also ductility of pure Mg. The overall tensile properties assessed in terms of work of fracture increased by almost 143% in the case of composite sample. An attempt is made in this study to correlate the tensile response of alloys and composite with their microstructural characteristics.