Dynamic tensile response of magnesium nanocomposites and the effect of nanoparticles

AZ31 Mg alloy and its composites, reinforced by different volume fractions (1 vol%, 1.4 vol% and 3 vol%) of 50-nm Al2O3 nanoparticles, were fabricated by a disintegrated melt deposition technique. The tensile mechanical behavior of these materials at strain rates spanning 10−4–103 s−1 was investigated. Compared to their monolithic counterpart, significantly increased ductility and yield stress of the nanocomposites under both low and high rate loading were observed, and indicate the positive effect of the nanoparticles. The addition of nanoparticles was found to increase the material strength by a constant value for both low and high rate loading, and decrease the strain rate sensitivity of the composites, and does not change the strain hardening behavior of AZ31. X-ray diffraction (XRD) results for AZ31 and AZ31/Al2O3 nanocomposite samples before testing, as well as after quasi-static and dynamic tension tests, indicate that (1) the nanoparticles alter the initial texture configuration; (2) addition of nanoparticles maintains the texture configuration during tensile tests. These are interpreted as the fundamental reason for enhancement of dislocation movement and increased ductility of the nanocomposites.