Characterization and strengthening mechanism of CNT/TiB₂ particulates added AZ91D composites

Abstract

In the current work, magnesium (AZ91D) matrix composites reinforced with different weight fractions (5, 10, and 15%) of titanium diboride (TiB2) and 1.5 wt.% percent carbon nanotubes (CNTs) are fabricated using stir casting. The improvements in mechanical, wear and corrosion resistance properties are evaluated as per ASTM guidelines. The synergistic strengthening effect of TiB2 and CNT is also studied. It was discovered that the AZ91D/(1.5CNT-10TiB2) composite outperformed other magnesium matrix composites in terms of strength and ductility. Experimental characterization and quantity analysis revealed that the load transfer process of CNT and thermal mismatch, grain refinement are the primary factors leading to the composite's increased tensile strength. Porosity tends to increase as a result of variance in thermal expansion coefficient of particles and matrix material, Orowan strengthening mechanism plays a prominent role towards enhancement of tensile strength. Because of the influence of synergistic strengthening, micro particles TiB2 increased the proportion of load transmission mechanisms and thermal mismatch facilitated the homogenous distribution of CNTs. Wear resistance and corrosion resistance increases with inclusion of CNTs and TiB2 content. Abrasive type wear mechanism is seen from the SEM image and the wear craters are also seen in all the SEM images, adding TiB2 considerably improves the cast composites resistance to corrosion because of grain refinement. Higher addition of TiB2 influences higher pitting corrosion due to poor grain refinement.

Effects of Mold Temperature on the Microstructures and Tensile Properties of the Thixoforged Graphite/AZ91D Composite

“…Magnesium alloys have been widely used in electronic products and transportation, with high specific strength and low density [1][2][3]. However, magnesium still has some shortcomings in meeting some extreme conditions [4]. To further improve the properties of magnesium, the fabrication of MMCs (metal-matrix composites) is the most common method, of which SiC, TiC, Al 2 O 3 , and Mg 2 Si are the relatively common strengthening particles.…”