Mechanical characterization of Mg-B4C nanocomposite fabricated at different strain rates

Magnesium has wide application in industry. The main purpose of this investigation was to improve the properties of magnesium by reinforcing it using B4C nanoparticles. The reinforced nanocomposites were fabricated using a powder compaction technique for 0, 1.5vol%, 3vol%, 5vol%, and 10vol% of B4C. Powder compaction was conducted using a split Hopkinson bar (SHB), drop hammer (DH), and Instron to reach different compaction loading rates. The compressive stress-strain curves of the samples were captured from quasi-static and dynamic tests carried out using an Instron and split Hopkinson pressure bar, respectively. Results revealed that, to achieve the highest improvement in ultimate strength, the contents of B4C were 1.5vol%, 3vol%, and 3vol% for Instron, DH, and SHB, respectively. These results also indicated that the effect of compaction type on the quasi-static strength of the samples was not as significant, although its effect on the dynamic strength of the samples was remarkable. The improvement in ultimate strength obtained from the quasi-static stress-strain curves of the samples (compared to pure Mg) varied from 9.9% for DH to 24% for SHB. The dynamic strength of the samples was improved (with respect to pure Mg) by 73%, 116%, and 141% for the specimens compacted by Instron, DH, and SHB, respectively. The improvement in strength was believed to be due to strengthening mechanisms, friction, adiabatic heating, and shock waves.