AZ91D/TiB2 Nanocomposites Fabricated by Solidification Nanoprocessing

作者：Choi Hongseok^*; Sun Yi; Slater Ben P; Konishi Hiromi; Li Xiaochun

来源：Advanced Engineering Materials, 2012, 14(5): 291-295.

DOI：10.1002/adem.201100313

AZ91D, as one of the most widely used casting magnesium alloys, still suffers from inadequate mechanical performances for various applications. Nanoparticles could be used to form high-performance magnesium matrix nanocomposites. Among all nanoparticles, TiB2 has great potentials to enhance the mechanical property of AZ91D. This paper studies the microstructures and mechanical property of AZ91D-TiB2 nanocomposites fabricated through solidification nanoprocessing. TiB2 nanoparticles with a diameter of 25?nm are effectively fed into the AZ91D melt through a newly developed automatic nanoparticle-feeding system. Ultrasonic cavitation is used to disperse these nanoparticles in AZ91D melt for casting. With 2.7?wt% (about 1.0?vol%) of TiB2 nanoparticles addition, the mechanical property of AZ91D is much enhanced (by 21, 16, and 48% for yield strength, tensile strength, and ductility, respectively). Microstructural analysis with optical microscope, SEM, and S/TEM show that a-Mg grain and a network of massive brittle intermetallic phase (beta-Mg17Al12) are simultaneously refined and modified. Further study suggests that the enhancement of mechanical properties of AZ91D is attributed not only to primary phase grain refinement, but also to the modification of intermetallic beta-Mg17Al12 by TiB2 nanoparticles.

• 出版日期2012-5