TEM and XRD Study of Nanostructured Composite Materials Reinforced with the Halloysite Particles

Abstract

In the present work selected results of TEM and XRD investigations of the new AA-6061 matrix composite materials reinforced with halloysite nanoparticles manufactured by mechanical alloying and hot extrusion are present. Halloysite nanotubes, being a clayey mineral of volcanic origin which is characterized by high porosity, large specific surface, high ion exchange and easy chemical and mechanical treatment, can be used as alternative reinforcement of metal matrix composite materials. The composite materials obtained as a result of mechanical alloying and hot extrusion are characterized with the structure of evenly distributed, disperse mineral phase particles in fine-grain matrix of AA-6061 alloy, facilitate the obtainment of higher values of strength properties, compared to the initial alloy. Thanks to HRTEM analysis, the occurrence of grains sized ca. 20÷30nm in the composite materials reinforced with halloysite nanotubes with 15% mass share has been confirmed. The crystallite size and lattice strain of the obtained composites were calculated from X-ray line broadening, applying different profiles of diffraction lines. The achieved values of crystallite size for composites powders after 6 hours of milling were in the range 65-150nm, depending on the calculation method.