Time-Dependent Plastic Deformation of Mg Nanocomposites: Ambient and Elevated Temperature Assessments

Magnesium (Mg) nanocomposites are promising materials for many lightweight engineering applications. By adding a nanoparticle phase, like carbon nanotubes (CNTs) to a Mg matrix phase, new strengthening mechanisms are activated and enable the resulting nanocomposite to have better mechanical properties, e.g., strength and ductility, than unreinforced Mg. The viability of using Mg-CNT nanocomposites in lieu of heavier structural metals in industrial dimensions, especially those at high temperatures, cannot be assessed until these materials have been comprehensively characterized. In the present project, the nanoindentation technique was used to assess the creep and hardness response of pure Mg and Mg reinforced with 0.25, 0.5, and 0.75 vol.% CNTs at room and elevated (373, 473, and 573 K) temperatures. This work has shown that CNTs improve strength and creep resistance of Mg matrices. It was found that the dominant creep mechanisms at room and elevated temperatures are not necessarily the same mechanism