MICROSTRUCTURE STUDY OF MIXTURES OF MICRO-POWDER Al AND NANO-POWDERS TiN, SiC AND Al2O3 PRODUSED BY TWO STAGE PROCESS

Abstract

Composite wires obtained from aluminum shell, micron-sized aluminum powder and nanosized TiN, SiC and Al2O3 powders were fabricated by a two-stage process. The stages included ultrasonic treatment and hot extrusion. TEM and SEM observations were performed to investigate the wires’ microstructure. Individual nanopowder particles as well as particle agglomerations were observed by two microscopic methods, as well as nanoparticles distribution and localization in the matrix. It was found that the observed nanoparticles and clusters were located in the volume of micron-sized Al particles and along the grain boundaries of the matrix. The provided EDX analysis confirms the presence of nanoparticles in the aluminum matrix. From the obtained results, it can be concluded that the two-stage fabrication process of nanocomposite wires leads to better wetting of the nanopowders from the aluminum melt. Nanocomposites obtained by mixing and extruding TiN, SiC and Al2O3 nanopowders and Al micropowder can be used as modifiers of aluminum alloys, as the nanoparticles will contribute to grain refinement and will participate as additional crystallization centers.