The time-dependent plastic deformation response of magnesium/carbon nanotube (CNT) nanocomposites containing 0.25, 0.5, and 0.75 vol% of carbon nanotubes is investigated through depth nanoindentation tests against monolithic pure magnesium in the present study. The Mg-CNT nanocomposite materials were successfully synthesized via a powder metallurgy technique coupled with microwave sintering followed by hot extrusion to produce 8-mm diameter, long solid bars. All depth-sensing indentation creep tests were conducted at ambient (room) temperature employing a diamond Berkovich pyramidal indenter. These tests are dual-stage, i.e., loading to a prescribed peak load of 50 mN, holding the peak load constant for a dwell period of 500 s, and finally unloading. Various strain rates of 0.01, 0.1, 1, and 10 s −1 were performed to assess the effects of strain rate and dwell time on the ambient temperature creep response of the Mg-CNT nanocomposites. The outcomes of these tests are explained through material hardness, microstructure, the extent of CNT content in each material, and strain rate sensitivity. Upon analyzing the nanoindentation creep tests, the dominant creep mechanism at room temperature was found to be a dislocation creep mechanism. It is also found that CNTs increase the creep resistance of magnesium. Findings of this study can be used as a starting point for a high-temperature creep study on Mg-CNT nanocomposites. This paper is a continued study from our group on time-dependent plastic deformation of Mg nanocomposites (i.e., see Haghshenas et al., Journal of Composite Materials,

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Abstract:: Several studies have reported the corrosion rates of magnesium carbon nanotube nanocomposites, but their cor-rosion behavior is still not well understood. Adding carbon nanotubes (CNTs) to magnesium (Mg) matrices almost always results in an increase in mechanical properties, e.g., increased elastic modulus, hardness, ultimate tensile strength, and yield strength. However, this increase in mechanical properties usually comes at the expense of compromised corrosion re-sistance. Galvanic interactions between the carbon nanotubes and the magnesium matrix are the usual culprits of nanocom-posite corrosion. It is desired to study the corrosion behavior of these materials further to create a nanocomposite that is less susceptible to corrosion from the start, i.e., the fabrication method. In the present review, four processing methods (Disin-tegrated Melt Deposition, Friction Stir Processing, Powder Metallurgy, and Ball Milling) which were used to successfully synthesize magnesium carbon nanotube nanocomposites and test their corrosion properties are discussed. Attempts are made to correlate processing methods to corresponding corrosion rates. It was found that the corrosion rates extracted from each reviewed study may not be readily comparable, and looking into nanocomposite coatings and carbon nanotube volume or weight percent optimization may be the best way to proceed. The findings of this investigation can be used as a starting point for the creation of a magnesium carbon nanotube nanocomposite which is less inherently susceptible to corrosion as this could take the “potential” out of the many potential applications of these novel materials.