Differentiating the mechanical response of hybridized Mg nano-composites as a function of strain rate

Abstract

The effect of strain rate change on tensile and compressive response of hybrid Mg/Al-CNT nano-composites synthesized through powder metallurgy route incorporating microwave assisted rapid sintering technique and hot extrusion is investigated in this work. It is important to characterize the effect of strain rate on mechanical response of a material that will be used in a structure which can undergo a high rate deformation (as in automobile crash) as well as during high velocity forming processes such as electromagnetic or electro hydraulic forming. Tensile and compressive tests for monolithic Mg along with its hybrid Mg/Al-CNT nano-composites counterparts at quasi-static and dynamic regimes were carried out using: (i) a servo hydraulic testing machine (MTS) and (b) a Split Hopkinson Pressure Bar (SHPB) apparatus with an average strain rate of 10 -4s -1 and 2×10 3s -1, respectively. The tremendous increase in strain rate led to a considerable increase in strength of monolithic Mg alongside hybrid nano-composites in both tension and compression. The presence of hybrid Al-CNT particles significantly assisted in improving mechanical response of Mg in both quasi-static and dynamic regimes. Considering the crystallographic texture, the different mechanical response of Mg due to the presence of hybrid Al-CNT particles as a function of strain rate in both tension and compression is differentiated here. © 2012 Elsevier B.V.